From 51c14f1a9c3edfd3ecac358fe0ff827e832914f5 Mon Sep 17 00:00:00 2001 From: GaidamakUA Date: Thu, 8 Oct 2015 15:37:34 +0300 Subject: [PATCH] Issue Fix #1779 --- .../ConcurrentHashMapV8.java | 4157 +++++++++++++++++ .../ConcurrentLinkedHashMap.java | 1574 +++++++ .../concurrentlinkedhashmap/EntryWeigher.java | 37 + .../EvictionListener.java | 45 + .../concurrentlinkedhashmap/LinkedDeque.java | 460 ++ .../concurrentlinkedhashmap/Weigher.java | 36 + .../concurrentlinkedhashmap/Weighers.java | 282 ++ .../concurrentlinkedhashmap/package-info.java | 41 + .../audionotes/AudioVideoNotesPlugin.java | 42 +- 9 files changed, 6655 insertions(+), 19 deletions(-) create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentHashMapV8.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentLinkedHashMap.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EntryWeigher.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EvictionListener.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/LinkedDeque.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weigher.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weighers.java create mode 100644 OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/package-info.java diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentHashMapV8.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentHashMapV8.java new file mode 100644 index 0000000000..9d0bcd5c12 --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentHashMapV8.java @@ -0,0 +1,4157 @@ +/* + * Written by Doug Lea with assistance from members of JCP JSR-166 + * Expert Group and released to the public domain, as explained at + * http://creativecommons.org/publicdomain/zero/1.0/ + */ +package com.googlecode.concurrentlinkedhashmap; + +import java.io.ObjectStreamField; +import java.io.Serializable; +import java.lang.reflect.ParameterizedType; +import java.lang.reflect.Type; +import java.util.AbstractMap; +import java.util.Arrays; +import java.util.Collection; +import java.util.ConcurrentModificationException; +import java.util.Enumeration; +import java.util.HashMap; +import java.util.Hashtable; +import java.util.Iterator; +import java.util.Map; +import java.util.NoSuchElementException; +import java.util.Set; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.locks.LockSupport; +import java.util.concurrent.locks.ReentrantLock; + +/* + * Bulk operations removed in Java 6 backport. + */ + +/** + * A hash table supporting full concurrency of retrievals and + * high expected concurrency for updates. This class obeys the + * same functional specification as {@link Hashtable}, and + * includes versions of methods corresponding to each method of + * {@code Hashtable}. However, even though all operations are + * thread-safe, retrieval operations do not entail locking, + * and there is not any support for locking the entire table + * in a way that prevents all access. This class is fully + * interoperable with {@code Hashtable} in programs that rely on its + * thread safety but not on its synchronization details. + * + *

Retrieval operations (including {@code get}) generally do not + * block, so may overlap with update operations (including {@code put} + * and {@code remove}). Retrievals reflect the results of the most + * recently completed update operations holding upon their + * onset. (More formally, an update operation for a given key bears a + * happens-before relation with any (non-null) retrieval for + * that key reporting the updated value.) For aggregate operations + * such as {@code putAll} and {@code clear}, concurrent retrievals may + * reflect insertion or removal of only some entries. Similarly, + * Iterators and Enumerations return elements reflecting the state of + * the hash table at some point at or since the creation of the + * iterator/enumeration. They do not throw {@link + * ConcurrentModificationException}. However, iterators are designed + * to be used by only one thread at a time. Bear in mind that the + * results of aggregate status methods including {@code size}, {@code + * isEmpty}, and {@code containsValue} are typically useful only when + * a map is not undergoing concurrent updates in other threads. + * Otherwise the results of these methods reflect transient states + * that may be adequate for monitoring or estimation purposes, but not + * for program control. + * + *

The table is dynamically expanded when there are too many + * collisions (i.e., keys that have distinct hash codes but fall into + * the same slot modulo the table size), with the expected average + * effect of maintaining roughly two bins per mapping (corresponding + * to a 0.75 load factor threshold for resizing). There may be much + * variance around this average as mappings are added and removed, but + * overall, this maintains a commonly accepted time/space tradeoff for + * hash tables. However, resizing this or any other kind of hash + * table may be a relatively slow operation. When possible, it is a + * good idea to provide a size estimate as an optional {@code + * initialCapacity} constructor argument. An additional optional + * {@code loadFactor} constructor argument provides a further means of + * customizing initial table capacity by specifying the table density + * to be used in calculating the amount of space to allocate for the + * given number of elements. Also, for compatibility with previous + * versions of this class, constructors may optionally specify an + * expected {@code concurrencyLevel} as an additional hint for + * internal sizing. Note that using many keys with exactly the same + * {@code hashCode()} is a sure way to slow down performance of any + * hash table. To ameliorate impact, when keys are {@link Comparable}, + * this class may use comparison order among keys to help break ties. + * + *

A {@link Set} projection of a ConcurrentHashMapV8 may be created + * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed + * (using {@link #keySet(Object)} when only keys are of interest, and the + * mapped values are (perhaps transiently) not used or all take the + * same mapping value. + * + *

This class and its views and iterators implement all of the + * optional methods of the {@link Map} and {@link Iterator} + * interfaces. + * + *

Like {@link Hashtable} but unlike {@link HashMap}, this class + * does not allow {@code null} to be used as a key or value. + * + *

ConcurrentHashMapV8s support a set of sequential and parallel bulk + * operations that are designed + * to be safely, and often sensibly, applied even with maps that are + * being concurrently updated by other threads; for example, when + * computing a snapshot summary of the values in a shared registry. + * There are three kinds of operation, each with four forms, accepting + * functions with Keys, Values, Entries, and (Key, Value) arguments + * and/or return values. Because the elements of a ConcurrentHashMapV8 + * are not ordered in any particular way, and may be processed in + * different orders in different parallel executions, the correctness + * of supplied functions should not depend on any ordering, or on any + * other objects or values that may transiently change while + * computation is in progress; and except for forEach actions, should + * ideally be side-effect-free. Bulk operations on {@link Entry} + * objects do not support method {@code setValue}. + * + *

+ * + *

These bulk operations accept a {@code parallelismThreshold} + * argument. Methods proceed sequentially if the current map size is + * estimated to be less than the given threshold. Using a value of + * {@code Long.MAX_VALUE} suppresses all parallelism. Using a value + * of {@code 1} results in maximal parallelism by partitioning into + * enough subtasks to fully utilize the {@link + * ForkJoinPool#commonPool()} that is used for all parallel + * computations. Normally, you would initially choose one of these + * extreme values, and then measure performance of using in-between + * values that trade off overhead versus throughput. + * + *

The concurrency properties of bulk operations follow + * from those of ConcurrentHashMapV8: Any non-null result returned + * from {@code get(key)} and related access methods bears a + * happens-before relation with the associated insertion or + * update. The result of any bulk operation reflects the + * composition of these per-element relations (but is not + * necessarily atomic with respect to the map as a whole unless it + * is somehow known to be quiescent). Conversely, because keys + * and values in the map are never null, null serves as a reliable + * atomic indicator of the current lack of any result. To + * maintain this property, null serves as an implicit basis for + * all non-scalar reduction operations. For the double, long, and + * int versions, the basis should be one that, when combined with + * any other value, returns that other value (more formally, it + * should be the identity element for the reduction). Most common + * reductions have these properties; for example, computing a sum + * with basis 0 or a minimum with basis MAX_VALUE. + * + *

Search and transformation functions provided as arguments + * should similarly return null to indicate the lack of any result + * (in which case it is not used). In the case of mapped + * reductions, this also enables transformations to serve as + * filters, returning null (or, in the case of primitive + * specializations, the identity basis) if the element should not + * be combined. You can create compound transformations and + * filterings by composing them yourself under this "null means + * there is nothing there now" rule before using them in search or + * reduce operations. + * + *

Methods accepting and/or returning Entry arguments maintain + * key-value associations. They may be useful for example when + * finding the key for the greatest value. Note that "plain" Entry + * arguments can be supplied using {@code new + * AbstractMap.SimpleEntry(k,v)}. + * + *

Bulk operations may complete abruptly, throwing an + * exception encountered in the application of a supplied + * function. Bear in mind when handling such exceptions that other + * concurrently executing functions could also have thrown + * exceptions, or would have done so if the first exception had + * not occurred. + * + *

Speedups for parallel compared to sequential forms are common + * but not guaranteed. Parallel operations involving brief functions + * on small maps may execute more slowly than sequential forms if the + * underlying work to parallelize the computation is more expensive + * than the computation itself. Similarly, parallelization may not + * lead to much actual parallelism if all processors are busy + * performing unrelated tasks. + * + *

All arguments to all task methods must be non-null. + * + *

jsr166e note: During transition, this class + * uses nested functional interfaces with different names but the + * same forms as those expected for JDK8. + * + *

This class is a member of the + * + * Java Collections Framework. + * + * @since 1.5 + * @author Doug Lea + * @param the type of keys maintained by this map + * @param the type of mapped values + */ +@SuppressWarnings("all") +class ConcurrentHashMapV8 extends AbstractMap + implements ConcurrentMap, Serializable { + private static final long serialVersionUID = 7249069246763182397L; + + /** + * An object for traversing and partitioning elements of a source. + * This interface provides a subset of the functionality of JDK8 + * java.util.Spliterator. + */ + public static interface ConcurrentHashMapSpliterator { + /** + * If possible, returns a new spliterator covering + * approximately one half of the elements, which will not be + * covered by this spliterator. Returns null if cannot be + * split. + */ + ConcurrentHashMapSpliterator trySplit(); + /** + * Returns an estimate of the number of elements covered by + * this Spliterator. + */ + long estimateSize(); + + /** Applies the action to each untraversed element */ + void forEachRemaining(Action action); + /** If an element remains, applies the action and returns true. */ + boolean tryAdvance(Action action); + } + + // Sams + /** Interface describing a void action of one argument */ + public interface Action { void apply(A a); } + /** Interface describing a void action of two arguments */ + public interface BiAction { void apply(A a, B b); } + /** Interface describing a function of one argument */ + public interface Fun { T apply(A a); } + /** Interface describing a function of two arguments */ + public interface BiFun { T apply(A a, B b); } + /** Interface describing a function mapping its argument to a double */ + public interface ObjectToDouble { double apply(A a); } + /** Interface describing a function mapping its argument to a long */ + public interface ObjectToLong { long apply(A a); } + /** Interface describing a function mapping its argument to an int */ + public interface ObjectToInt {int apply(A a); } + /** Interface describing a function mapping two arguments to a double */ + public interface ObjectByObjectToDouble { double apply(A a, B b); } + /** Interface describing a function mapping two arguments to a long */ + public interface ObjectByObjectToLong { long apply(A a, B b); } + /** Interface describing a function mapping two arguments to an int */ + public interface ObjectByObjectToInt {int apply(A a, B b); } + /** Interface describing a function mapping two doubles to a double */ + public interface DoubleByDoubleToDouble { double apply(double a, double b); } + /** Interface describing a function mapping two longs to a long */ + public interface LongByLongToLong { long apply(long a, long b); } + /** Interface describing a function mapping two ints to an int */ + public interface IntByIntToInt { int apply(int a, int b); } + + /* + * Overview: + * + * The primary design goal of this hash table is to maintain + * concurrent readability (typically method get(), but also + * iterators and related methods) while minimizing update + * contention. Secondary goals are to keep space consumption about + * the same or better than java.util.HashMap, and to support high + * initial insertion rates on an empty table by many threads. + * + * This map usually acts as a binned (bucketed) hash table. Each + * key-value mapping is held in a Node. Most nodes are instances + * of the basic Node class with hash, key, value, and next + * fields. However, various subclasses exist: TreeNodes are + * arranged in balanced trees, not lists. TreeBins hold the roots + * of sets of TreeNodes. ForwardingNodes are placed at the heads + * of bins during resizing. ReservationNodes are used as + * placeholders while establishing values in computeIfAbsent and + * related methods. The types TreeBin, ForwardingNode, and + * ReservationNode do not hold normal user keys, values, or + * hashes, and are readily distinguishable during search etc + * because they have negative hash fields and null key and value + * fields. (These special nodes are either uncommon or transient, + * so the impact of carrying around some unused fields is + * insignificant.) + * + * The table is lazily initialized to a power-of-two size upon the + * first insertion. Each bin in the table normally contains a + * list of Nodes (most often, the list has only zero or one Node). + * Table accesses require volatile/atomic reads, writes, and + * CASes. Because there is no other way to arrange this without + * adding further indirections, we use intrinsics + * (sun.misc.Unsafe) operations. + * + * We use the top (sign) bit of Node hash fields for control + * purposes -- it is available anyway because of addressing + * constraints. Nodes with negative hash fields are specially + * handled or ignored in map methods. + * + * Insertion (via put or its variants) of the first node in an + * empty bin is performed by just CASing it to the bin. This is + * by far the most common case for put operations under most + * key/hash distributions. Other update operations (insert, + * delete, and replace) require locks. We do not want to waste + * the space required to associate a distinct lock object with + * each bin, so instead use the first node of a bin list itself as + * a lock. Locking support for these locks relies on builtin + * "synchronized" monitors. + * + * Using the first node of a list as a lock does not by itself + * suffice though: When a node is locked, any update must first + * validate that it is still the first node after locking it, and + * retry if not. Because new nodes are always appended to lists, + * once a node is first in a bin, it remains first until deleted + * or the bin becomes invalidated (upon resizing). + * + * The main disadvantage of per-bin locks is that other update + * operations on other nodes in a bin list protected by the same + * lock can stall, for example when user equals() or mapping + * functions take a long time. However, statistically, under + * random hash codes, this is not a common problem. Ideally, the + * frequency of nodes in bins follows a Poisson distribution + * (http://en.wikipedia.org/wiki/Poisson_distribution) with a + * parameter of about 0.5 on average, given the resizing threshold + * of 0.75, although with a large variance because of resizing + * granularity. Ignoring variance, the expected occurrences of + * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The + * first values are: + * + * 0: 0.60653066 + * 1: 0.30326533 + * 2: 0.07581633 + * 3: 0.01263606 + * 4: 0.00157952 + * 5: 0.00015795 + * 6: 0.00001316 + * 7: 0.00000094 + * 8: 0.00000006 + * more: less than 1 in ten million + * + * Lock contention probability for two threads accessing distinct + * elements is roughly 1 / (8 * #elements) under random hashes. + * + * Actual hash code distributions encountered in practice + * sometimes deviate significantly from uniform randomness. This + * includes the case when N > (1<<30), so some keys MUST collide. + * Similarly for dumb or hostile usages in which multiple keys are + * designed to have identical hash codes or ones that differs only + * in masked-out high bits. So we use a secondary strategy that + * applies when the number of nodes in a bin exceeds a + * threshold. These TreeBins use a balanced tree to hold nodes (a + * specialized form of red-black trees), bounding search time to + * O(log N). Each search step in a TreeBin is at least twice as + * slow as in a regular list, but given that N cannot exceed + * (1<<64) (before running out of addresses) this bounds search + * steps, lock hold times, etc, to reasonable constants (roughly + * 100 nodes inspected per operation worst case) so long as keys + * are Comparable (which is very common -- String, Long, etc). + * TreeBin nodes (TreeNodes) also maintain the same "next" + * traversal pointers as regular nodes, so can be traversed in + * iterators in the same way. + * + * The table is resized when occupancy exceeds a percentage + * threshold (nominally, 0.75, but see below). Any thread + * noticing an overfull bin may assist in resizing after the + * initiating thread allocates and sets up the replacement + * array. However, rather than stalling, these other threads may + * proceed with insertions etc. The use of TreeBins shields us + * from the worst case effects of overfilling while resizes are in + * progress. Resizing proceeds by transferring bins, one by one, + * from the table to the next table. To enable concurrency, the + * next table must be (incrementally) prefilled with place-holders + * serving as reverse forwarders to the old table. Because we are + * using power-of-two expansion, the elements from each bin must + * either stay at same index, or move with a power of two + * offset. We eliminate unnecessary node creation by catching + * cases where old nodes can be reused because their next fields + * won't change. On average, only about one-sixth of them need + * cloning when a table doubles. The nodes they replace will be + * garbage collectable as soon as they are no longer referenced by + * any reader thread that may be in the midst of concurrently + * traversing table. Upon transfer, the old table bin contains + * only a special forwarding node (with hash field "MOVED") that + * contains the next table as its key. On encountering a + * forwarding node, access and update operations restart, using + * the new table. + * + * Each bin transfer requires its bin lock, which can stall + * waiting for locks while resizing. However, because other + * threads can join in and help resize rather than contend for + * locks, average aggregate waits become shorter as resizing + * progresses. The transfer operation must also ensure that all + * accessible bins in both the old and new table are usable by any + * traversal. This is arranged by proceeding from the last bin + * (table.length - 1) up towards the first. Upon seeing a + * forwarding node, traversals (see class Traverser) arrange to + * move to the new table without revisiting nodes. However, to + * ensure that no intervening nodes are skipped, bin splitting can + * only begin after the associated reverse-forwarders are in + * place. + * + * The traversal scheme also applies to partial traversals of + * ranges of bins (via an alternate Traverser constructor) + * to support partitioned aggregate operations. Also, read-only + * operations give up if ever forwarded to a null table, which + * provides support for shutdown-style clearing, which is also not + * currently implemented. + * + * Lazy table initialization minimizes footprint until first use, + * and also avoids resizings when the first operation is from a + * putAll, constructor with map argument, or deserialization. + * These cases attempt to override the initial capacity settings, + * but harmlessly fail to take effect in cases of races. + * + * The element count is maintained using a specialization of + * LongAdder. We need to incorporate a specialization rather than + * just use a LongAdder in order to access implicit + * contention-sensing that leads to creation of multiple + * CounterCells. The counter mechanics avoid contention on + * updates but can encounter cache thrashing if read too + * frequently during concurrent access. To avoid reading so often, + * resizing under contention is attempted only upon adding to a + * bin already holding two or more nodes. Under uniform hash + * distributions, the probability of this occurring at threshold + * is around 13%, meaning that only about 1 in 8 puts check + * threshold (and after resizing, many fewer do so). + * + * TreeBins use a special form of comparison for search and + * related operations (which is the main reason we cannot use + * existing collections such as TreeMaps). TreeBins contain + * Comparable elements, but may contain others, as well as + * elements that are Comparable but not necessarily Comparable for + * the same T, so we cannot invoke compareTo among them. To handle + * this, the tree is ordered primarily by hash value, then by + * Comparable.compareTo order if applicable. On lookup at a node, + * if elements are not comparable or compare as 0 then both left + * and right children may need to be searched in the case of tied + * hash values. (This corresponds to the full list search that + * would be necessary if all elements were non-Comparable and had + * tied hashes.) On insertion, to keep a total ordering (or as + * close as is required here) across rebalancings, we compare + * classes and identityHashCodes as tie-breakers. The red-black + * balancing code is updated from pre-jdk-collections + * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) + * based in turn on Cormen, Leiserson, and Rivest "Introduction to + * Algorithms" (CLR). + * + * TreeBins also require an additional locking mechanism. While + * list traversal is always possible by readers even during + * updates, tree traversal is not, mainly because of tree-rotations + * that may change the root node and/or its linkages. TreeBins + * include a simple read-write lock mechanism parasitic on the + * main bin-synchronization strategy: Structural adjustments + * associated with an insertion or removal are already bin-locked + * (and so cannot conflict with other writers) but must wait for + * ongoing readers to finish. Since there can be only one such + * waiter, we use a simple scheme using a single "waiter" field to + * block writers. However, readers need never block. If the root + * lock is held, they proceed along the slow traversal path (via + * next-pointers) until the lock becomes available or the list is + * exhausted, whichever comes first. These cases are not fast, but + * maximize aggregate expected throughput. + * + * Maintaining API and serialization compatibility with previous + * versions of this class introduces several oddities. Mainly: We + * leave untouched but unused constructor arguments refering to + * concurrencyLevel. We accept a loadFactor constructor argument, + * but apply it only to initial table capacity (which is the only + * time that we can guarantee to honor it.) We also declare an + * unused "Segment" class that is instantiated in minimal form + * only when serializing. + * + * Also, solely for compatibility with previous versions of this + * class, it extends AbstractMap, even though all of its methods + * are overridden, so it is just useless baggage. + * + * This file is organized to make things a little easier to follow + * while reading than they might otherwise: First the main static + * declarations and utilities, then fields, then main public + * methods (with a few factorings of multiple public methods into + * internal ones), then sizing methods, trees, traversers, and + * bulk operations. + */ + + /* ---------------- Constants -------------- */ + + /** + * The largest possible table capacity. This value must be + * exactly 1<<30 to stay within Java array allocation and indexing + * bounds for power of two table sizes, and is further required + * because the top two bits of 32bit hash fields are used for + * control purposes. + */ + private static final int MAXIMUM_CAPACITY = 1 << 30; + + /** + * The default initial table capacity. Must be a power of 2 + * (i.e., at least 1) and at most MAXIMUM_CAPACITY. + */ + private static final int DEFAULT_CAPACITY = 16; + + /** + * The largest possible (non-power of two) array size. + * Needed by toArray and related methods. + */ + static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; + + /** + * The default concurrency level for this table. Unused but + * defined for compatibility with previous versions of this class. + */ + private static final int DEFAULT_CONCURRENCY_LEVEL = 16; + + /** + * The load factor for this table. Overrides of this value in + * constructors affect only the initial table capacity. The + * actual floating point value isn't normally used -- it is + * simpler to use expressions such as {@code n - (n >>> 2)} for + * the associated resizing threshold. + */ + private static final float LOAD_FACTOR = 0.75f; + + /** + * The bin count threshold for using a tree rather than list for a + * bin. Bins are converted to trees when adding an element to a + * bin with at least this many nodes. The value must be greater + * than 2, and should be at least 8 to mesh with assumptions in + * tree removal about conversion back to plain bins upon + * shrinkage. + */ + static final int TREEIFY_THRESHOLD = 8; + + /** + * The bin count threshold for untreeifying a (split) bin during a + * resize operation. Should be less than TREEIFY_THRESHOLD, and at + * most 6 to mesh with shrinkage detection under removal. + */ + static final int UNTREEIFY_THRESHOLD = 6; + + /** + * The smallest table capacity for which bins may be treeified. + * (Otherwise the table is resized if too many nodes in a bin.) + * The value should be at least 4 * TREEIFY_THRESHOLD to avoid + * conflicts between resizing and treeification thresholds. + */ + static final int MIN_TREEIFY_CAPACITY = 64; + + /** + * Minimum number of rebinnings per transfer step. Ranges are + * subdivided to allow multiple resizer threads. This value + * serves as a lower bound to avoid resizers encountering + * excessive memory contention. The value should be at least + * DEFAULT_CAPACITY. + */ + private static final int MIN_TRANSFER_STRIDE = 16; + + /* + * Encodings for Node hash fields. See above for explanation. + */ + static final int MOVED = -1; // hash for forwarding nodes + static final int TREEBIN = -2; // hash for roots of trees + static final int RESERVED = -3; // hash for transient reservations + static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash + + /** Number of CPUS, to place bounds on some sizings */ + static final int NCPU = Runtime.getRuntime().availableProcessors(); + + /** For serialization compatibility. */ + private static final ObjectStreamField[] serialPersistentFields = { + new ObjectStreamField("segments", Segment[].class), + new ObjectStreamField("segmentMask", Integer.TYPE), + new ObjectStreamField("segmentShift", Integer.TYPE) + }; + + /* ---------------- Nodes -------------- */ + + /** + * Key-value entry. This class is never exported out as a + * user-mutable Map.Entry (i.e., one supporting setValue; see + * MapEntry below), but can be used for read-only traversals used + * in bulk tasks. Subclasses of Node with a negative hash field + * are special, and contain null keys and values (but are never + * exported). Otherwise, keys and vals are never null. + */ + static class Node implements Entry { + final int hash; + final K key; + volatile V val; + volatile Node next; + + Node(int hash, K key, V val, Node next) { + this.hash = hash; + this.key = key; + this.val = val; + this.next = next; + } + + @Override + public final K getKey() { return key; } + @Override + public final V getValue() { return val; } + @Override + public final int hashCode() { return key.hashCode() ^ val.hashCode(); } + @Override + public final String toString(){ return key + "=" + val; } + @Override + public final V setValue(V value) { + throw new UnsupportedOperationException(); + } + + @Override + public final boolean equals(Object o) { + Object k, v, u; Entry e; + return ((o instanceof Entry) && + (k = (e = (Entry)o).getKey()) != null && + (v = e.getValue()) != null && + (k == key || k.equals(key)) && + (v == (u = val) || v.equals(u))); + } + + /** + * Virtualized support for map.get(); overridden in subclasses. + */ + Node find(int h, Object k) { + Node e = this; + if (k != null) { + do { + K ek; + if (e.hash == h && + ((ek = e.key) == k || (ek != null && k.equals(ek)))) + return e; + } while ((e = e.next) != null); + } + return null; + } + } + + /* ---------------- Static utilities -------------- */ + + /** + * Spreads (XORs) higher bits of hash to lower and also forces top + * bit to 0. Because the table uses power-of-two masking, sets of + * hashes that vary only in bits above the current mask will + * always collide. (Among known examples are sets of Float keys + * holding consecutive whole numbers in small tables.) So we + * apply a transform that spreads the impact of higher bits + * downward. There is a tradeoff between speed, utility, and + * quality of bit-spreading. Because many common sets of hashes + * are already reasonably distributed (so don't benefit from + * spreading), and because we use trees to handle large sets of + * collisions in bins, we just XOR some shifted bits in the + * cheapest possible way to reduce systematic lossage, as well as + * to incorporate impact of the highest bits that would otherwise + * never be used in index calculations because of table bounds. + */ + static final int spread(int h) { + return (h ^ (h >>> 16)) & HASH_BITS; + } + + /** + * Returns a power of two table size for the given desired capacity. + * See Hackers Delight, sec 3.2 + */ + private static final int tableSizeFor(int c) { + int n = c - 1; + n |= n >>> 1; + n |= n >>> 2; + n |= n >>> 4; + n |= n >>> 8; + n |= n >>> 16; + return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; + } + + /** + * Returns x's Class if it is of the form "class C implements + * Comparable", else null. + */ + static Class comparableClassFor(Object x) { + if (x instanceof Comparable) { + Class c; Type[] ts, as; Type t; ParameterizedType p; + if ((c = x.getClass()) == String.class) // bypass checks + return c; + if ((ts = c.getGenericInterfaces()) != null) { + for (int i = 0; i < ts.length; ++i) { + if (((t = ts[i]) instanceof ParameterizedType) && + ((p = (ParameterizedType)t).getRawType() == + Comparable.class) && + (as = p.getActualTypeArguments()) != null && + as.length == 1 && as[0] == c) // type arg is c + return c; + } + } + } + return null; + } + + /** + * Returns k.compareTo(x) if x matches kc (k's screened comparable + * class), else 0. + */ + @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable + static int compareComparables(Class kc, Object k, Object x) { + return (x == null || x.getClass() != kc ? 0 : + ((Comparable)k).compareTo(x)); + } + + /* ---------------- Table element access -------------- */ + + /* + * Volatile access methods are used for table elements as well as + * elements of in-progress next table while resizing. All uses of + * the tab arguments must be null checked by callers. All callers + * also paranoically precheck that tab's length is not zero (or an + * equivalent check), thus ensuring that any index argument taking + * the form of a hash value anded with (length - 1) is a valid + * index. Note that, to be correct wrt arbitrary concurrency + * errors by users, these checks must operate on local variables, + * which accounts for some odd-looking inline assignments below. + * Note that calls to setTabAt always occur within locked regions, + * and so in principle require only release ordering, not need + * full volatile semantics, but are currently coded as volatile + * writes to be conservative. + */ + + @SuppressWarnings("unchecked") + static final Node tabAt(Node[] tab, int i) { + return (Node)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE); + } + + static final boolean casTabAt(Node[] tab, int i, + Node c, Node v) { + return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v); + } + + static final void setTabAt(Node[] tab, int i, Node v) { + U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v); + } + + /* ---------------- Fields -------------- */ + + /** + * The array of bins. Lazily initialized upon first insertion. + * Size is always a power of two. Accessed directly by iterators. + */ + transient volatile Node[] table; + + /** + * The next table to use; non-null only while resizing. + */ + private transient volatile Node[] nextTable; + + /** + * Base counter value, used mainly when there is no contention, + * but also as a fallback during table initialization + * races. Updated via CAS. + */ + private transient volatile long baseCount; + + /** + * Table initialization and resizing control. When negative, the + * table is being initialized or resized: -1 for initialization, + * else -(1 + the number of active resizing threads). Otherwise, + * when table is null, holds the initial table size to use upon + * creation, or 0 for default. After initialization, holds the + * next element count value upon which to resize the table. + */ + private transient volatile int sizeCtl; + + /** + * The next table index (plus one) to split while resizing. + */ + private transient volatile int transferIndex; + + /** + * The least available table index to split while resizing. + */ + private transient volatile int transferOrigin; + + /** + * Spinlock (locked via CAS) used when resizing and/or creating CounterCells. + */ + private transient volatile int cellsBusy; + + /** + * Table of counter cells. When non-null, size is a power of 2. + */ + private transient volatile CounterCell[] counterCells; + + // views + private transient KeySetView keySet; + private transient ValuesView values; + private transient EntrySetView entrySet; + + + /* ---------------- Public operations -------------- */ + + /** + * Creates a new, empty map with the default initial table size (16). + */ + public ConcurrentHashMapV8() { + } + + /** + * Creates a new, empty map with an initial table size + * accommodating the specified number of elements without the need + * to dynamically resize. + * + * @param initialCapacity The implementation performs internal + * sizing to accommodate this many elements. + * @throws IllegalArgumentException if the initial capacity of + * elements is negative + */ + public ConcurrentHashMapV8(int initialCapacity) { + if (initialCapacity < 0) + throw new IllegalArgumentException(); + int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? + MAXIMUM_CAPACITY : + tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); + this.sizeCtl = cap; + } + + /** + * Creates a new map with the same mappings as the given map. + * + * @param m the map + */ + public ConcurrentHashMapV8(Map m) { + this.sizeCtl = DEFAULT_CAPACITY; + putAll(m); + } + + /** + * Creates a new, empty map with an initial table size based on + * the given number of elements ({@code initialCapacity}) and + * initial table density ({@code loadFactor}). + * + * @param initialCapacity the initial capacity. The implementation + * performs internal sizing to accommodate this many elements, + * given the specified load factor. + * @param loadFactor the load factor (table density) for + * establishing the initial table size + * @throws IllegalArgumentException if the initial capacity of + * elements is negative or the load factor is nonpositive + * + * @since 1.6 + */ + public ConcurrentHashMapV8(int initialCapacity, float loadFactor) { + this(initialCapacity, loadFactor, 1); + } + + /** + * Creates a new, empty map with an initial table size based on + * the given number of elements ({@code initialCapacity}), table + * density ({@code loadFactor}), and number of concurrently + * updating threads ({@code concurrencyLevel}). + * + * @param initialCapacity the initial capacity. The implementation + * performs internal sizing to accommodate this many elements, + * given the specified load factor. + * @param loadFactor the load factor (table density) for + * establishing the initial table size + * @param concurrencyLevel the estimated number of concurrently + * updating threads. The implementation may use this value as + * a sizing hint. + * @throws IllegalArgumentException if the initial capacity is + * negative or the load factor or concurrencyLevel are + * nonpositive + */ + public ConcurrentHashMapV8(int initialCapacity, + float loadFactor, int concurrencyLevel) { + if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) + throw new IllegalArgumentException(); + if (initialCapacity < concurrencyLevel) // Use at least as many bins + initialCapacity = concurrencyLevel; // as estimated threads + long size = (long)(1.0 + initialCapacity / loadFactor); + int cap = (size >= MAXIMUM_CAPACITY) ? + MAXIMUM_CAPACITY : tableSizeFor((int)size); + this.sizeCtl = cap; + } + + // Original (since JDK1.2) Map methods + + /** + * {@inheritDoc} + */ + @Override + public int size() { + long n = sumCount(); + return ((n < 0L) ? 0 : + (n > Integer.MAX_VALUE) ? Integer.MAX_VALUE : + (int)n); + } + + /** + * {@inheritDoc} + */ + @Override + public boolean isEmpty() { + return sumCount() <= 0L; // ignore transient negative values + } + + /** + * Returns the value to which the specified key is mapped, + * or {@code null} if this map contains no mapping for the key. + * + *

More formally, if this map contains a mapping from a key + * {@code k} to a value {@code v} such that {@code key.equals(k)}, + * then this method returns {@code v}; otherwise it returns + * {@code null}. (There can be at most one such mapping.) + * + * @throws NullPointerException if the specified key is null + */ + @Override + public V get(Object key) { + Node[] tab; Node e, p; int n, eh; K ek; + int h = spread(key.hashCode()); + if ((tab = table) != null && (n = tab.length) > 0 && + (e = tabAt(tab, (n - 1) & h)) != null) { + if ((eh = e.hash) == h) { + if ((ek = e.key) == key || (ek != null && key.equals(ek))) + return e.val; + } + else if (eh < 0) + return (p = e.find(h, key)) != null ? p.val : null; + while ((e = e.next) != null) { + if (e.hash == h && + ((ek = e.key) == key || (ek != null && key.equals(ek)))) + return e.val; + } + } + return null; + } + + /** + * Tests if the specified object is a key in this table. + * + * @param key possible key + * @return {@code true} if and only if the specified object + * is a key in this table, as determined by the + * {@code equals} method; {@code false} otherwise + * @throws NullPointerException if the specified key is null + */ + @Override + public boolean containsKey(Object key) { + return get(key) != null; + } + + /** + * Returns {@code true} if this map maps one or more keys to the + * specified value. Note: This method may require a full traversal + * of the map, and is much slower than method {@code containsKey}. + * + * @param value value whose presence in this map is to be tested + * @return {@code true} if this map maps one or more keys to the + * specified value + * @throws NullPointerException if the specified value is null + */ + @Override + public boolean containsValue(Object value) { + if (value == null) + throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + V v; + if ((v = p.val) == value || (v != null && value.equals(v))) + return true; + } + } + return false; + } + + /** + * Maps the specified key to the specified value in this table. + * Neither the key nor the value can be null. + * + *

The value can be retrieved by calling the {@code get} method + * with a key that is equal to the original key. + * + * @param key key with which the specified value is to be associated + * @param value value to be associated with the specified key + * @return the previous value associated with {@code key}, or + * {@code null} if there was no mapping for {@code key} + * @throws NullPointerException if the specified key or value is null + */ + @Override + public V put(K key, V value) { + return putVal(key, value, false); + } + + /** Implementation for put and putIfAbsent */ + final V putVal(K key, V value, boolean onlyIfAbsent) { + if (key == null || value == null) throw new NullPointerException(); + int hash = spread(key.hashCode()); + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) { + if (casTabAt(tab, i, null, + new Node(hash, key, value, null))) + break; // no lock when adding to empty bin + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + V oldVal = null; + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f;; ++binCount) { + K ek; + if (e.hash == hash && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + oldVal = e.val; + if (!onlyIfAbsent) + e.val = value; + break; + } + Node pred = e; + if ((e = e.next) == null) { + pred.next = new Node(hash, key, + value, null); + break; + } + } + } + else if (f instanceof TreeBin) { + Node p; + binCount = 2; + if ((p = ((TreeBin)f).putTreeVal(hash, key, + value)) != null) { + oldVal = p.val; + if (!onlyIfAbsent) + p.val = value; + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + if (oldVal != null) + return oldVal; + break; + } + } + } + addCount(1L, binCount); + return null; + } + + /** + * Copies all of the mappings from the specified map to this one. + * These mappings replace any mappings that this map had for any of the + * keys currently in the specified map. + * + * @param m mappings to be stored in this map + */ + @Override + public void putAll(Map m) { + tryPresize(m.size()); + for (Entry e : m.entrySet()) + putVal(e.getKey(), e.getValue(), false); + } + + /** + * Removes the key (and its corresponding value) from this map. + * This method does nothing if the key is not in the map. + * + * @param key the key that needs to be removed + * @return the previous value associated with {@code key}, or + * {@code null} if there was no mapping for {@code key} + * @throws NullPointerException if the specified key is null + */ + @Override + public V remove(Object key) { + return replaceNode(key, null, null); + } + + /** + * Implementation for the four public remove/replace methods: + * Replaces node value with v, conditional upon match of cv if + * non-null. If resulting value is null, delete. + */ + final V replaceNode(Object key, V value, Object cv) { + int hash = spread(key.hashCode()); + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0 || + (f = tabAt(tab, i = (n - 1) & hash)) == null) + break; + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + V oldVal = null; + boolean validated = false; + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + validated = true; + for (Node e = f, pred = null;;) { + K ek; + if (e.hash == hash && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + V ev = e.val; + if (cv == null || cv == ev || + (ev != null && cv.equals(ev))) { + oldVal = ev; + if (value != null) + e.val = value; + else if (pred != null) + pred.next = e.next; + else + setTabAt(tab, i, e.next); + } + break; + } + pred = e; + if ((e = e.next) == null) + break; + } + } + else if (f instanceof TreeBin) { + validated = true; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null && + (p = r.findTreeNode(hash, key, null)) != null) { + V pv = p.val; + if (cv == null || cv == pv || + (pv != null && cv.equals(pv))) { + oldVal = pv; + if (value != null) + p.val = value; + else if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + } + if (validated) { + if (oldVal != null) { + if (value == null) + addCount(-1L, -1); + return oldVal; + } + break; + } + } + } + return null; + } + + /** + * Removes all of the mappings from this map. + */ + @Override + public void clear() { + long delta = 0L; // negative number of deletions + int i = 0; + Node[] tab = table; + while (tab != null && i < tab.length) { + int fh; + Node f = tabAt(tab, i); + if (f == null) + ++i; + else if ((fh = f.hash) == MOVED) { + tab = helpTransfer(tab, f); + i = 0; // restart + } + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + Node p = (fh >= 0 ? f : + (f instanceof TreeBin) ? + ((TreeBin)f).first : null); + while (p != null) { + --delta; + p = p.next; + } + setTabAt(tab, i++, null); + } + } + } + } + if (delta != 0L) + addCount(delta, -1); + } + + /** + * Returns a {@link Set} view of the keys contained in this map. + * The set is backed by the map, so changes to the map are + * reflected in the set, and vice-versa. The set supports element + * removal, which removes the corresponding mapping from this map, + * via the {@code Iterator.remove}, {@code Set.remove}, + * {@code removeAll}, {@code retainAll}, and {@code clear} + * operations. It does not support the {@code add} or + * {@code addAll} operations. + * + *

The view's {@code iterator} is a "weakly consistent" iterator + * that will never throw {@link ConcurrentModificationException}, + * and guarantees to traverse elements as they existed upon + * construction of the iterator, and may (but is not guaranteed to) + * reflect any modifications subsequent to construction. + * + * @return the set view + */ + @Override + public KeySetView keySet() { + KeySetView ks; + return (ks = keySet) != null ? ks : (keySet = new KeySetView(this, null)); + } + + /** + * Returns a {@link Collection} view of the values contained in this map. + * The collection is backed by the map, so changes to the map are + * reflected in the collection, and vice-versa. The collection + * supports element removal, which removes the corresponding + * mapping from this map, via the {@code Iterator.remove}, + * {@code Collection.remove}, {@code removeAll}, + * {@code retainAll}, and {@code clear} operations. It does not + * support the {@code add} or {@code addAll} operations. + * + *

The view's {@code iterator} is a "weakly consistent" iterator + * that will never throw {@link ConcurrentModificationException}, + * and guarantees to traverse elements as they existed upon + * construction of the iterator, and may (but is not guaranteed to) + * reflect any modifications subsequent to construction. + * + * @return the collection view + */ + @Override + public Collection values() { + ValuesView vs; + return (vs = values) != null ? vs : (values = new ValuesView(this)); + } + + /** + * Returns a {@link Set} view of the mappings contained in this map. + * The set is backed by the map, so changes to the map are + * reflected in the set, and vice-versa. The set supports element + * removal, which removes the corresponding mapping from the map, + * via the {@code Iterator.remove}, {@code Set.remove}, + * {@code removeAll}, {@code retainAll}, and {@code clear} + * operations. + * + *

The view's {@code iterator} is a "weakly consistent" iterator + * that will never throw {@link ConcurrentModificationException}, + * and guarantees to traverse elements as they existed upon + * construction of the iterator, and may (but is not guaranteed to) + * reflect any modifications subsequent to construction. + * + * @return the set view + */ + @Override + public Set> entrySet() { + EntrySetView es; + return (es = entrySet) != null ? es : (entrySet = new EntrySetView(this)); + } + + /** + * Returns the hash code value for this {@link Map}, i.e., + * the sum of, for each key-value pair in the map, + * {@code key.hashCode() ^ value.hashCode()}. + * + * @return the hash code value for this map + */ + @Override + public int hashCode() { + int h = 0; + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + h += p.key.hashCode() ^ p.val.hashCode(); + } + return h; + } + + /** + * Returns a string representation of this map. The string + * representation consists of a list of key-value mappings (in no + * particular order) enclosed in braces ("{@code {}}"). Adjacent + * mappings are separated by the characters {@code ", "} (comma + * and space). Each key-value mapping is rendered as the key + * followed by an equals sign ("{@code =}") followed by the + * associated value. + * + * @return a string representation of this map + */ + @Override + public String toString() { + Node[] t; + int f = (t = table) == null ? 0 : t.length; + Traverser it = new Traverser(t, f, 0, f); + StringBuilder sb = new StringBuilder(); + sb.append('{'); + Node p; + if ((p = it.advance()) != null) { + for (;;) { + K k = p.key; + V v = p.val; + sb.append(k == this ? "(this Map)" : k); + sb.append('='); + sb.append(v == this ? "(this Map)" : v); + if ((p = it.advance()) == null) + break; + sb.append(',').append(' '); + } + } + return sb.append('}').toString(); + } + + /** + * Compares the specified object with this map for equality. + * Returns {@code true} if the given object is a map with the same + * mappings as this map. This operation may return misleading + * results if either map is concurrently modified during execution + * of this method. + * + * @param o object to be compared for equality with this map + * @return {@code true} if the specified object is equal to this map + */ + @Override + public boolean equals(Object o) { + if (o != this) { + if (!(o instanceof Map)) + return false; + Map m = (Map) o; + Node[] t; + int f = (t = table) == null ? 0 : t.length; + Traverser it = new Traverser(t, f, 0, f); + for (Node p; (p = it.advance()) != null; ) { + V val = p.val; + Object v = m.get(p.key); + if (v == null || (v != val && !v.equals(val))) + return false; + } + for (Entry e : m.entrySet()) { + Object mk, mv, v; + if ((mk = e.getKey()) == null || + (mv = e.getValue()) == null || + (v = get(mk)) == null || + (mv != v && !mv.equals(v))) + return false; + } + } + return true; + } + + /** + * Stripped-down version of helper class used in previous version, + * declared for the sake of serialization compatibility + */ + static class Segment extends ReentrantLock implements Serializable { + private static final long serialVersionUID = 2249069246763182397L; + final float loadFactor; + Segment(float lf) { this.loadFactor = lf; } + } + + /** + * Saves the state of the {@code ConcurrentHashMapV8} instance to a + * stream (i.e., serializes it). + * @param s the stream + * @throws java.io.IOException if an I/O error occurs + * @serialData + * the key (Object) and value (Object) + * for each key-value mapping, followed by a null pair. + * The key-value mappings are emitted in no particular order. + */ + private void writeObject(java.io.ObjectOutputStream s) + throws java.io.IOException { + // For serialization compatibility + // Emulate segment calculation from previous version of this class + int sshift = 0; + int ssize = 1; + while (ssize < DEFAULT_CONCURRENCY_LEVEL) { + ++sshift; + ssize <<= 1; + } + int segmentShift = 32 - sshift; + int segmentMask = ssize - 1; + @SuppressWarnings("unchecked") Segment[] segments = (Segment[]) + new Segment[DEFAULT_CONCURRENCY_LEVEL]; + for (int i = 0; i < segments.length; ++i) + segments[i] = new Segment(LOAD_FACTOR); + s.putFields().put("segments", segments); + s.putFields().put("segmentShift", segmentShift); + s.putFields().put("segmentMask", segmentMask); + s.writeFields(); + + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + s.writeObject(p.key); + s.writeObject(p.val); + } + } + s.writeObject(null); + s.writeObject(null); + segments = null; // throw away + } + + /** + * Reconstitutes the instance from a stream (that is, deserializes it). + * @param s the stream + * @throws ClassNotFoundException if the class of a serialized object + * could not be found + * @throws java.io.IOException if an I/O error occurs + */ + private void readObject(java.io.ObjectInputStream s) + throws java.io.IOException, ClassNotFoundException { + /* + * To improve performance in typical cases, we create nodes + * while reading, then place in table once size is known. + * However, we must also validate uniqueness and deal with + * overpopulated bins while doing so, which requires + * specialized versions of putVal mechanics. + */ + sizeCtl = -1; // force exclusion for table construction + s.defaultReadObject(); + long size = 0L; + Node p = null; + for (;;) { + @SuppressWarnings("unchecked") K k = (K) s.readObject(); + @SuppressWarnings("unchecked") V v = (V) s.readObject(); + if (k != null && v != null) { + p = new Node(spread(k.hashCode()), k, v, p); + ++size; + } + else + break; + } + if (size == 0L) + sizeCtl = 0; + else { + int n; + if (size >= MAXIMUM_CAPACITY >>> 1) + n = MAXIMUM_CAPACITY; + else { + int sz = (int)size; + n = tableSizeFor(sz + (sz >>> 1) + 1); + } + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] tab = new Node[n]; + int mask = n - 1; + long added = 0L; + while (p != null) { + boolean insertAtFront; + Node next = p.next, first; + int h = p.hash, j = h & mask; + if ((first = tabAt(tab, j)) == null) + insertAtFront = true; + else { + K k = p.key; + if (first.hash < 0) { + TreeBin t = (TreeBin)first; + if (t.putTreeVal(h, k, p.val) == null) + ++added; + insertAtFront = false; + } + else { + int binCount = 0; + insertAtFront = true; + Node q; K qk; + for (q = first; q != null; q = q.next) { + if (q.hash == h && + ((qk = q.key) == k || + (qk != null && k.equals(qk)))) { + insertAtFront = false; + break; + } + ++binCount; + } + if (insertAtFront && binCount >= TREEIFY_THRESHOLD) { + insertAtFront = false; + ++added; + p.next = first; + TreeNode hd = null, tl = null; + for (q = p; q != null; q = q.next) { + TreeNode t = new TreeNode + (q.hash, q.key, q.val, null, null); + if ((t.prev = tl) == null) + hd = t; + else + tl.next = t; + tl = t; + } + setTabAt(tab, j, new TreeBin(hd)); + } + } + } + if (insertAtFront) { + ++added; + p.next = first; + setTabAt(tab, j, p); + } + p = next; + } + table = tab; + sizeCtl = n - (n >>> 2); + baseCount = added; + } + } + + // ConcurrentMap methods + + /** + * {@inheritDoc} + * + * @return the previous value associated with the specified key, + * or {@code null} if there was no mapping for the key + * @throws NullPointerException if the specified key or value is null + */ + @Override + public V putIfAbsent(K key, V value) { + return putVal(key, value, true); + } + + /** + * {@inheritDoc} + * + * @throws NullPointerException if the specified key is null + */ + @Override + public boolean remove(Object key, Object value) { + if (key == null) + throw new NullPointerException(); + return value != null && replaceNode(key, null, value) != null; + } + + /** + * {@inheritDoc} + * + * @throws NullPointerException if any of the arguments are null + */ + @Override + public boolean replace(K key, V oldValue, V newValue) { + if (key == null || oldValue == null || newValue == null) + throw new NullPointerException(); + return replaceNode(key, newValue, oldValue) != null; + } + + /** + * {@inheritDoc} + * + * @return the previous value associated with the specified key, + * or {@code null} if there was no mapping for the key + * @throws NullPointerException if the specified key or value is null + */ + @Override + public V replace(K key, V value) { + if (key == null || value == null) + throw new NullPointerException(); + return replaceNode(key, value, null); + } + + // Overrides of JDK8+ Map extension method defaults + + /** + * Returns the value to which the specified key is mapped, or the + * given default value if this map contains no mapping for the + * key. + * + * @param key the key whose associated value is to be returned + * @param defaultValue the value to return if this map contains + * no mapping for the given key + * @return the mapping for the key, if present; else the default value + * @throws NullPointerException if the specified key is null + */ + public V getOrDefault(Object key, V defaultValue) { + V v; + return (v = get(key)) == null ? defaultValue : v; + } + + public void forEach(BiAction action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + action.apply(p.key, p.val); + } + } + } + + public void replaceAll(BiFun function) { + if (function == null) throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + V oldValue = p.val; + for (K key = p.key;;) { + V newValue = function.apply(key, oldValue); + if (newValue == null) + throw new NullPointerException(); + if (replaceNode(key, newValue, oldValue) != null || + (oldValue = get(key)) == null) + break; + } + } + } + } + + /** + * If the specified key is not already associated with a value, + * attempts to compute its value using the given mapping function + * and enters it into this map unless {@code null}. The entire + * method invocation is performed atomically, so the function is + * applied at most once per key. Some attempted update operations + * on this map by other threads may be blocked while computation + * is in progress, so the computation should be short and simple, + * and must not attempt to update any other mappings of this map. + * + * @param key key with which the specified value is to be associated + * @param mappingFunction the function to compute a value + * @return the current (existing or computed) value associated with + * the specified key, or null if the computed value is null + * @throws NullPointerException if the specified key or mappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the mappingFunction does so, + * in which case the mapping is left unestablished + */ + public V computeIfAbsent(K key, Fun mappingFunction) { + if (key == null || mappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { + Node r = new ReservationNode(); + synchronized (r) { + if (casTabAt(tab, i, null, r)) { + binCount = 1; + Node node = null; + try { + if ((val = mappingFunction.apply(key)) != null) + node = new Node(h, key, val, null); + } finally { + setTabAt(tab, i, node); + } + } + } + if (binCount != 0) + break; + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + boolean added = false; + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f;; ++binCount) { + K ek; V ev; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = e.val; + break; + } + Node pred = e; + if ((e = e.next) == null) { + if ((val = mappingFunction.apply(key)) != null) { + added = true; + pred.next = new Node(h, key, val, null); + } + break; + } + } + } + else if (f instanceof TreeBin) { + binCount = 2; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null && + (p = r.findTreeNode(h, key, null)) != null) + val = p.val; + else if ((val = mappingFunction.apply(key)) != null) { + added = true; + t.putTreeVal(h, key, val); + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + if (!added) + return val; + break; + } + } + } + if (val != null) + addCount(1L, binCount); + return val; + } + + /** + * If the value for the specified key is present, attempts to + * compute a new mapping given the key and its current mapped + * value. The entire method invocation is performed atomically. + * Some attempted update operations on this map by other threads + * may be blocked while computation is in progress, so the + * computation should be short and simple, and must not attempt to + * update any other mappings of this map. + * + * @param key key with which a value may be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or remappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V computeIfPresent(K key, BiFun remappingFunction) { + if (key == null || remappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int delta = 0; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) + break; + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f, pred = null;; ++binCount) { + K ek; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = remappingFunction.apply(key, e.val); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) + break; + } + } + else if (f instanceof TreeBin) { + binCount = 2; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null && + (p = r.findTreeNode(h, key, null)) != null) { + val = remappingFunction.apply(key, p.val); + if (val != null) + p.val = val; + else { + delta = -1; + if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + } + if (binCount != 0) + break; + } + } + if (delta != 0) + addCount(delta, binCount); + return val; + } + + /** + * Attempts to compute a mapping for the specified key and its + * current mapped value (or {@code null} if there is no current + * mapping). The entire method invocation is performed atomically. + * Some attempted update operations on this map by other threads + * may be blocked while computation is in progress, so the + * computation should be short and simple, and must not attempt to + * update any other mappings of this Map. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or remappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V compute(K key, + BiFun remappingFunction) { + if (key == null || remappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int delta = 0; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { + Node r = new ReservationNode(); + synchronized (r) { + if (casTabAt(tab, i, null, r)) { + binCount = 1; + Node node = null; + try { + if ((val = remappingFunction.apply(key, null)) != null) { + delta = 1; + node = new Node(h, key, val, null); + } + } finally { + setTabAt(tab, i, node); + } + } + } + if (binCount != 0) + break; + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f, pred = null;; ++binCount) { + K ek; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = remappingFunction.apply(key, e.val); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) { + val = remappingFunction.apply(key, null); + if (val != null) { + delta = 1; + pred.next = + new Node(h, key, val, null); + } + break; + } + } + } + else if (f instanceof TreeBin) { + binCount = 1; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null) + p = r.findTreeNode(h, key, null); + else + p = null; + V pv = (p == null) ? null : p.val; + val = remappingFunction.apply(key, pv); + if (val != null) { + if (p != null) + p.val = val; + else { + delta = 1; + t.putTreeVal(h, key, val); + } + } + else if (p != null) { + delta = -1; + if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + break; + } + } + } + if (delta != 0) + addCount(delta, binCount); + return val; + } + + /** + * If the specified key is not already associated with a + * (non-null) value, associates it with the given value. + * Otherwise, replaces the value with the results of the given + * remapping function, or removes if {@code null}. The entire + * method invocation is performed atomically. Some attempted + * update operations on this map by other threads may be blocked + * while computation is in progress, so the computation should be + * short and simple, and must not attempt to update any other + * mappings of this Map. + * + * @param key key with which the specified value is to be associated + * @param value the value to use if absent + * @param remappingFunction the function to recompute a value if present + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or the + * remappingFunction is null + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V merge(K key, V value, BiFun remappingFunction) { + if (key == null || value == null || remappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int delta = 0; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { + if (casTabAt(tab, i, null, new Node(h, key, value, null))) { + delta = 1; + val = value; + break; + } + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f, pred = null;; ++binCount) { + K ek; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = remappingFunction.apply(e.val, value); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) { + delta = 1; + val = value; + pred.next = + new Node(h, key, val, null); + break; + } + } + } + else if (f instanceof TreeBin) { + binCount = 2; + TreeBin t = (TreeBin)f; + TreeNode r = t.root; + TreeNode p = (r == null) ? null : + r.findTreeNode(h, key, null); + val = (p == null) ? value : + remappingFunction.apply(p.val, value); + if (val != null) { + if (p != null) + p.val = val; + else { + delta = 1; + t.putTreeVal(h, key, val); + } + } + else if (p != null) { + delta = -1; + if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + break; + } + } + } + if (delta != 0) + addCount(delta, binCount); + return val; + } + + // Hashtable legacy methods + + /** + * Legacy method testing if some key maps into the specified value + * in this table. This method is identical in functionality to + * {@link #containsValue(Object)}, and exists solely to ensure + * full compatibility with class {@link Hashtable}, + * which supported this method prior to introduction of the + * Java Collections framework. + * + * @param value a value to search for + * @return {@code true} if and only if some key maps to the + * {@code value} argument in this table as + * determined by the {@code equals} method; + * {@code false} otherwise + * @throws NullPointerException if the specified value is null + */ + @Deprecated public boolean contains(Object value) { + return containsValue(value); + } + + /** + * Returns an enumeration of the keys in this table. + * + * @return an enumeration of the keys in this table + * @see #keySet() + */ + public Enumeration keys() { + Node[] t; + int f = (t = table) == null ? 0 : t.length; + return new KeyIterator(t, f, 0, f, this); + } + + /** + * Returns an enumeration of the values in this table. + * + * @return an enumeration of the values in this table + * @see #values() + */ + public Enumeration elements() { + Node[] t; + int f = (t = table) == null ? 0 : t.length; + return new ValueIterator(t, f, 0, f, this); + } + + // ConcurrentHashMapV8-only methods + + /** + * Returns the number of mappings. This method should be used + * instead of {@link #size} because a ConcurrentHashMapV8 may + * contain more mappings than can be represented as an int. The + * value returned is an estimate; the actual count may differ if + * there are concurrent insertions or removals. + * + * @return the number of mappings + * @since 1.8 + */ + public long mappingCount() { + long n = sumCount(); + return (n < 0L) ? 0L : n; // ignore transient negative values + } + + /** + * Creates a new {@link Set} backed by a ConcurrentHashMapV8 + * from the given type to {@code Boolean.TRUE}. + * + * @return the new set + * @since 1.8 + */ + public static KeySetView newKeySet() { + return new KeySetView + (new ConcurrentHashMapV8(), Boolean.TRUE); + } + + /** + * Creates a new {@link Set} backed by a ConcurrentHashMapV8 + * from the given type to {@code Boolean.TRUE}. + * + * @param initialCapacity The implementation performs internal + * sizing to accommodate this many elements. + * @return the new set + * @throws IllegalArgumentException if the initial capacity of + * elements is negative + * @since 1.8 + */ + public static KeySetView newKeySet(int initialCapacity) { + return new KeySetView + (new ConcurrentHashMapV8(initialCapacity), Boolean.TRUE); + } + + /** + * Returns a {@link Set} view of the keys in this map, using the + * given common mapped value for any additions (i.e., {@link + * Collection#add} and {@link Collection#addAll(Collection)}). + * This is of course only appropriate if it is acceptable to use + * the same value for all additions from this view. + * + * @param mappedValue the mapped value to use for any additions + * @return the set view + * @throws NullPointerException if the mappedValue is null + */ + public KeySetView keySet(V mappedValue) { + if (mappedValue == null) + throw new NullPointerException(); + return new KeySetView(this, mappedValue); + } + + /* ---------------- Special Nodes -------------- */ + + /** + * A node inserted at head of bins during transfer operations. + */ + static final class ForwardingNode extends Node { + final Node[] nextTable; + ForwardingNode(Node[] tab) { + super(MOVED, null, null, null); + this.nextTable = tab; + } + + @Override + Node find(int h, Object k) { + // loop to avoid arbitrarily deep recursion on forwarding nodes + outer: for (Node[] tab = nextTable;;) { + Node e; int n; + if (k == null || tab == null || (n = tab.length) == 0 || + (e = tabAt(tab, (n - 1) & h)) == null) + return null; + for (;;) { + int eh; K ek; + if ((eh = e.hash) == h && + ((ek = e.key) == k || (ek != null && k.equals(ek)))) + return e; + if (eh < 0) { + if (e instanceof ForwardingNode) { + tab = ((ForwardingNode)e).nextTable; + continue outer; + } + else + return e.find(h, k); + } + if ((e = e.next) == null) + return null; + } + } + } + } + + /** + * A place-holder node used in computeIfAbsent and compute + */ + static final class ReservationNode extends Node { + ReservationNode() { + super(RESERVED, null, null, null); + } + + @Override + Node find(int h, Object k) { + return null; + } + } + + /* ---------------- Table Initialization and Resizing -------------- */ + + /** + * Initializes table, using the size recorded in sizeCtl. + */ + private final Node[] initTable() { + Node[] tab; int sc; + while ((tab = table) == null || tab.length == 0) { + if ((sc = sizeCtl) < 0) + Thread.yield(); // lost initialization race; just spin + else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if ((tab = table) == null || tab.length == 0) { + int n = (sc > 0) ? sc : DEFAULT_CAPACITY; + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] nt = new Node[n]; + table = tab = nt; + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + break; + } + } + return tab; + } + + /** + * Adds to count, and if table is too small and not already + * resizing, initiates transfer. If already resizing, helps + * perform transfer if work is available. Rechecks occupancy + * after a transfer to see if another resize is already needed + * because resizings are lagging additions. + * + * @param x the count to add + * @param check if <0, don't check resize, if <= 1 only check if uncontended + */ + private final void addCount(long x, int check) { + CounterCell[] as; long b, s; + if ((as = counterCells) != null || + !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) { + CounterHashCode hc; CounterCell a; long v; int m; + boolean uncontended = true; + if ((hc = threadCounterHashCode.get()) == null || + as == null || (m = as.length - 1) < 0 || + (a = as[m & hc.code]) == null || + !(uncontended = + U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) { + fullAddCount(x, hc, uncontended); + return; + } + if (check <= 1) + return; + s = sumCount(); + } + if (check >= 0) { + Node[] tab, nt; int sc; + while (s >= (sc = sizeCtl) && (tab = table) != null && + tab.length < MAXIMUM_CAPACITY) { + if (sc < 0) { + if (sc == -1 || transferIndex <= transferOrigin || + (nt = nextTable) == null) + break; + if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) + transfer(tab, nt); + } + else if (U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + s = sumCount(); + } + } + } + + /** + * Helps transfer if a resize is in progress. + */ + final Node[] helpTransfer(Node[] tab, Node f) { + Node[] nextTab; int sc; + if ((f instanceof ForwardingNode) && + (nextTab = ((ForwardingNode)f).nextTable) != null) { + if (nextTab == nextTable && tab == table && + transferIndex > transferOrigin && (sc = sizeCtl) < -1 && + U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) + transfer(tab, nextTab); + return nextTab; + } + return table; + } + + /** + * Tries to presize table to accommodate the given number of elements. + * + * @param size number of elements (doesn't need to be perfectly accurate) + */ + private final void tryPresize(int size) { + int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : + tableSizeFor(size + (size >>> 1) + 1); + int sc; + while ((sc = sizeCtl) >= 0) { + Node[] tab = table; int n; + if (tab == null || (n = tab.length) == 0) { + n = (sc > c) ? sc : c; + if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if (table == tab) { + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] nt = new Node[n]; + table = nt; + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + } + } + else if (c <= sc || n >= MAXIMUM_CAPACITY) + break; + else if (tab == table && + U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + } + } + + /** + * Moves and/or copies the nodes in each bin to new table. See + * above for explanation. + */ + private final void transfer(Node[] tab, Node[] nextTab) { + int n = tab.length, stride; + if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) + stride = MIN_TRANSFER_STRIDE; // subdivide range + if (nextTab == null) { // initiating + try { + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] nt = new Node[n << 1]; + nextTab = nt; + } catch (Throwable ex) { // try to cope with OOME + sizeCtl = Integer.MAX_VALUE; + return; + } + nextTable = nextTab; + transferOrigin = n; + transferIndex = n; + ForwardingNode rev = new ForwardingNode(tab); + for (int k = n; k > 0;) { // progressively reveal ready slots + int nextk = (k > stride) ? k - stride : 0; + for (int m = nextk; m < k; ++m) + nextTab[m] = rev; + for (int m = n + nextk; m < n + k; ++m) + nextTab[m] = rev; + U.putOrderedInt(this, TRANSFERORIGIN, k = nextk); + } + } + int nextn = nextTab.length; + ForwardingNode fwd = new ForwardingNode(nextTab); + boolean advance = true; + boolean finishing = false; // to ensure sweep before committing nextTab + for (int i = 0, bound = 0;;) { + int nextIndex, nextBound, fh; Node f; + while (advance) { + if (--i >= bound || finishing) + advance = false; + else if ((nextIndex = transferIndex) <= transferOrigin) { + i = -1; + advance = false; + } + else if (U.compareAndSwapInt + (this, TRANSFERINDEX, nextIndex, + nextBound = (nextIndex > stride ? + nextIndex - stride : 0))) { + bound = nextBound; + i = nextIndex - 1; + advance = false; + } + } + if (i < 0 || i >= n || i + n >= nextn) { + if (finishing) { + nextTable = null; + table = nextTab; + sizeCtl = (n << 1) - (n >>> 1); + return; + } + for (int sc;;) { + if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) { + if (sc != -1) + return; + finishing = advance = true; + i = n; // recheck before commit + break; + } + } + } + else if ((f = tabAt(tab, i)) == null) { + if (casTabAt(tab, i, null, fwd)) { + setTabAt(nextTab, i, null); + setTabAt(nextTab, i + n, null); + advance = true; + } + } + else if ((fh = f.hash) == MOVED) + advance = true; // already processed + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + Node ln, hn; + if (fh >= 0) { + int runBit = fh & n; + Node lastRun = f; + for (Node p = f.next; p != null; p = p.next) { + int b = p.hash & n; + if (b != runBit) { + runBit = b; + lastRun = p; + } + } + if (runBit == 0) { + ln = lastRun; + hn = null; + } + else { + hn = lastRun; + ln = null; + } + for (Node p = f; p != lastRun; p = p.next) { + int ph = p.hash; K pk = p.key; V pv = p.val; + if ((ph & n) == 0) + ln = new Node(ph, pk, pv, ln); + else + hn = new Node(ph, pk, pv, hn); + } + setTabAt(nextTab, i, ln); + setTabAt(nextTab, i + n, hn); + setTabAt(tab, i, fwd); + advance = true; + } + else if (f instanceof TreeBin) { + TreeBin t = (TreeBin)f; + TreeNode lo = null, loTail = null; + TreeNode hi = null, hiTail = null; + int lc = 0, hc = 0; + for (Node e = t.first; e != null; e = e.next) { + int h = e.hash; + TreeNode p = new TreeNode + (h, e.key, e.val, null, null); + if ((h & n) == 0) { + if ((p.prev = loTail) == null) + lo = p; + else + loTail.next = p; + loTail = p; + ++lc; + } + else { + if ((p.prev = hiTail) == null) + hi = p; + else + hiTail.next = p; + hiTail = p; + ++hc; + } + } + ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) : + (hc != 0) ? new TreeBin(lo) : t; + hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) : + (lc != 0) ? new TreeBin(hi) : t; + setTabAt(nextTab, i, ln); + setTabAt(nextTab, i + n, hn); + setTabAt(tab, i, fwd); + advance = true; + } + } + } + } + } + } + + /* ---------------- Conversion from/to TreeBins -------------- */ + + /** + * Replaces all linked nodes in bin at given index unless table is + * too small, in which case resizes instead. + */ + private final void treeifyBin(Node[] tab, int index) { + Node b; int n, sc; + if (tab != null) { + if ((n = tab.length) < MIN_TREEIFY_CAPACITY) { + if (tab == table && (sc = sizeCtl) >= 0 && + U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + } + else if ((b = tabAt(tab, index)) != null && b.hash >= 0) { + synchronized (b) { + if (tabAt(tab, index) == b) { + TreeNode hd = null, tl = null; + for (Node e = b; e != null; e = e.next) { + TreeNode p = + new TreeNode(e.hash, e.key, e.val, + null, null); + if ((p.prev = tl) == null) + hd = p; + else + tl.next = p; + tl = p; + } + setTabAt(tab, index, new TreeBin(hd)); + } + } + } + } + } + + /** + * Returns a list on non-TreeNodes replacing those in given list. + */ + static Node untreeify(Node b) { + Node hd = null, tl = null; + for (Node q = b; q != null; q = q.next) { + Node p = new Node(q.hash, q.key, q.val, null); + if (tl == null) + hd = p; + else + tl.next = p; + tl = p; + } + return hd; + } + + /* ---------------- TreeNodes -------------- */ + + /** + * Nodes for use in TreeBins + */ + static final class TreeNode extends Node { + TreeNode parent; // red-black tree links + TreeNode left; + TreeNode right; + TreeNode prev; // needed to unlink next upon deletion + boolean red; + + TreeNode(int hash, K key, V val, Node next, + TreeNode parent) { + super(hash, key, val, next); + this.parent = parent; + } + + @Override + Node find(int h, Object k) { + return findTreeNode(h, k, null); + } + + /** + * Returns the TreeNode (or null if not found) for the given key + * starting at given root. + */ + final TreeNode findTreeNode(int h, Object k, Class kc) { + if (k != null) { + TreeNode p = this; + do { + int ph, dir; K pk; TreeNode q; + TreeNode pl = p.left, pr = p.right; + if ((ph = p.hash) > h) + p = pl; + else if (ph < h) + p = pr; + else if ((pk = p.key) == k || (pk != null && k.equals(pk))) + return p; + else if (pl == null) + p = pr; + else if (pr == null) + p = pl; + else if ((kc != null || + (kc = comparableClassFor(k)) != null) && + (dir = compareComparables(kc, k, pk)) != 0) + p = (dir < 0) ? pl : pr; + else if ((q = pr.findTreeNode(h, k, kc)) != null) + return q; + else + p = pl; + } while (p != null); + } + return null; + } + } + + /* ---------------- TreeBins -------------- */ + + /** + * TreeNodes used at the heads of bins. TreeBins do not hold user + * keys or values, but instead point to list of TreeNodes and + * their root. They also maintain a parasitic read-write lock + * forcing writers (who hold bin lock) to wait for readers (who do + * not) to complete before tree restructuring operations. + */ + static final class TreeBin extends Node { + TreeNode root; + volatile TreeNode first; + volatile Thread waiter; + volatile int lockState; + // values for lockState + static final int WRITER = 1; // set while holding write lock + static final int WAITER = 2; // set when waiting for write lock + static final int READER = 4; // increment value for setting read lock + + /** + * Tie-breaking utility for ordering insertions when equal + * hashCodes and non-comparable. We don't require a total + * order, just a consistent insertion rule to maintain + * equivalence across rebalancings. Tie-breaking further than + * necessary simplifies testing a bit. + */ + static int tieBreakOrder(Object a, Object b) { + int d; + if (a == null || b == null || + (d = a.getClass().getName(). + compareTo(b.getClass().getName())) == 0) + d = (System.identityHashCode(a) <= System.identityHashCode(b) ? + -1 : 1); + return d; + } + + /** + * Creates bin with initial set of nodes headed by b. + */ + TreeBin(TreeNode b) { + super(TREEBIN, null, null, null); + this.first = b; + TreeNode r = null; + for (TreeNode x = b, next; x != null; x = next) { + next = (TreeNode)x.next; + x.left = x.right = null; + if (r == null) { + x.parent = null; + x.red = false; + r = x; + } + else { + K k = x.key; + int h = x.hash; + Class kc = null; + for (TreeNode p = r;;) { + int dir, ph; + K pk = p.key; + if ((ph = p.hash) > h) + dir = -1; + else if (ph < h) + dir = 1; + else if ((kc == null && + (kc = comparableClassFor(k)) == null) || + (dir = compareComparables(kc, k, pk)) == 0) + dir = tieBreakOrder(k, pk); + TreeNode xp = p; + if ((p = (dir <= 0) ? p.left : p.right) == null) { + x.parent = xp; + if (dir <= 0) + xp.left = x; + else + xp.right = x; + r = balanceInsertion(r, x); + break; + } + } + } + } + this.root = r; + assert checkInvariants(root); + } + + /** + * Acquires write lock for tree restructuring. + */ + private final void lockRoot() { + if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER)) + contendedLock(); // offload to separate method + } + + /** + * Releases write lock for tree restructuring. + */ + private final void unlockRoot() { + lockState = 0; + } + + /** + * Possibly blocks awaiting root lock. + */ + private final void contendedLock() { + boolean waiting = false; + for (int s;;) { + if (((s = lockState) & WRITER) == 0) { + if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) { + if (waiting) + waiter = null; + return; + } + } + else if ((s | WAITER) == 0) { + if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) { + waiting = true; + waiter = Thread.currentThread(); + } + } + else if (waiting) + LockSupport.park(this); + } + } + + /** + * Returns matching node or null if none. Tries to search + * using tree comparisons from root, but continues linear + * search when lock not available. + */ +@Override +final Node find(int h, Object k) { + if (k != null) { + for (Node e = first; e != null; e = e.next) { + int s; K ek; + if (((s = lockState) & (WAITER|WRITER)) != 0) { + if (e.hash == h && + ((ek = e.key) == k || (ek != null && k.equals(ek)))) + return e; + } + else if (U.compareAndSwapInt(this, LOCKSTATE, s, + s + READER)) { + TreeNode r, p; + try { + p = ((r = root) == null ? null : + r.findTreeNode(h, k, null)); + } finally { + Thread w; + int ls; + do {} while (!U.compareAndSwapInt + (this, LOCKSTATE, + ls = lockState, ls - READER)); + if (ls == (READER|WAITER) && (w = waiter) != null) + LockSupport.unpark(w); + } + return p; + } + } + } + return null; + } + + /** + * Finds or adds a node. + * @return null if added + */ + final TreeNode putTreeVal(int h, K k, V v) { + Class kc = null; + boolean searched = false; + for (TreeNode p = root;;) { + int dir, ph; K pk; + if (p == null) { + first = root = new TreeNode(h, k, v, null, null); + break; + } + else if ((ph = p.hash) > h) + dir = -1; + else if (ph < h) + dir = 1; + else if ((pk = p.key) == k || (pk != null && k.equals(pk))) + return p; + else if ((kc == null && + (kc = comparableClassFor(k)) == null) || + (dir = compareComparables(kc, k, pk)) == 0) { + if (!searched) { + TreeNode q, ch; + searched = true; + if (((ch = p.left) != null && + (q = ch.findTreeNode(h, k, kc)) != null) || + ((ch = p.right) != null && + (q = ch.findTreeNode(h, k, kc)) != null)) + return q; + } + dir = tieBreakOrder(k, pk); + } + + TreeNode xp = p; + if ((p = (dir <= 0) ? p.left : p.right) == null) { + TreeNode x, f = first; + first = x = new TreeNode(h, k, v, f, xp); + if (f != null) + f.prev = x; + if (dir <= 0) + xp.left = x; + else + xp.right = x; + if (!xp.red) + x.red = true; + else { + lockRoot(); + try { + root = balanceInsertion(root, x); + } finally { + unlockRoot(); + } + } + break; + } + } + assert checkInvariants(root); + return null; + } + + /** + * Removes the given node, that must be present before this + * call. This is messier than typical red-black deletion code + * because we cannot swap the contents of an interior node + * with a leaf successor that is pinned by "next" pointers + * that are accessible independently of lock. So instead we + * swap the tree linkages. + * + * @return true if now too small, so should be untreeified + */ + final boolean removeTreeNode(TreeNode p) { + TreeNode next = (TreeNode)p.next; + TreeNode pred = p.prev; // unlink traversal pointers + TreeNode r, rl; + if (pred == null) + first = next; + else + pred.next = next; + if (next != null) + next.prev = pred; + if (first == null) { + root = null; + return true; + } + if ((r = root) == null || r.right == null || // too small + (rl = r.left) == null || rl.left == null) + return true; + lockRoot(); + try { + TreeNode replacement; + TreeNode pl = p.left; + TreeNode pr = p.right; + if (pl != null && pr != null) { + TreeNode s = pr, sl; + while ((sl = s.left) != null) // find successor + s = sl; + boolean c = s.red; s.red = p.red; p.red = c; // swap colors + TreeNode sr = s.right; + TreeNode pp = p.parent; + if (s == pr) { // p was s's direct parent + p.parent = s; + s.right = p; + } + else { + TreeNode sp = s.parent; + if ((p.parent = sp) != null) { + if (s == sp.left) + sp.left = p; + else + sp.right = p; + } + if ((s.right = pr) != null) + pr.parent = s; + } + p.left = null; + if ((p.right = sr) != null) + sr.parent = p; + if ((s.left = pl) != null) + pl.parent = s; + if ((s.parent = pp) == null) + r = s; + else if (p == pp.left) + pp.left = s; + else + pp.right = s; + if (sr != null) + replacement = sr; + else + replacement = p; + } + else if (pl != null) + replacement = pl; + else if (pr != null) + replacement = pr; + else + replacement = p; + if (replacement != p) { + TreeNode pp = replacement.parent = p.parent; + if (pp == null) + r = replacement; + else if (p == pp.left) + pp.left = replacement; + else + pp.right = replacement; + p.left = p.right = p.parent = null; + } + + root = (p.red) ? r : balanceDeletion(r, replacement); + + if (p == replacement) { // detach pointers + TreeNode pp; + if ((pp = p.parent) != null) { + if (p == pp.left) + pp.left = null; + else if (p == pp.right) + pp.right = null; + p.parent = null; + } + } + } finally { + unlockRoot(); + } + assert checkInvariants(root); + return false; + } + + /* ------------------------------------------------------------ */ + // Red-black tree methods, all adapted from CLR + + static TreeNode rotateLeft(TreeNode root, + TreeNode p) { + TreeNode r, pp, rl; + if (p != null && (r = p.right) != null) { + if ((rl = p.right = r.left) != null) + rl.parent = p; + if ((pp = r.parent = p.parent) == null) + (root = r).red = false; + else if (pp.left == p) + pp.left = r; + else + pp.right = r; + r.left = p; + p.parent = r; + } + return root; + } + + static TreeNode rotateRight(TreeNode root, + TreeNode p) { + TreeNode l, pp, lr; + if (p != null && (l = p.left) != null) { + if ((lr = p.left = l.right) != null) + lr.parent = p; + if ((pp = l.parent = p.parent) == null) + (root = l).red = false; + else if (pp.right == p) + pp.right = l; + else + pp.left = l; + l.right = p; + p.parent = l; + } + return root; + } + + static TreeNode balanceInsertion(TreeNode root, + TreeNode x) { + x.red = true; + for (TreeNode xp, xpp, xppl, xppr;;) { + if ((xp = x.parent) == null) { + x.red = false; + return x; + } + else if (!xp.red || (xpp = xp.parent) == null) + return root; + if (xp == (xppl = xpp.left)) { + if ((xppr = xpp.right) != null && xppr.red) { + xppr.red = false; + xp.red = false; + xpp.red = true; + x = xpp; + } + else { + if (x == xp.right) { + root = rotateLeft(root, x = xp); + xpp = (xp = x.parent) == null ? null : xp.parent; + } + if (xp != null) { + xp.red = false; + if (xpp != null) { + xpp.red = true; + root = rotateRight(root, xpp); + } + } + } + } + else { + if (xppl != null && xppl.red) { + xppl.red = false; + xp.red = false; + xpp.red = true; + x = xpp; + } + else { + if (x == xp.left) { + root = rotateRight(root, x = xp); + xpp = (xp = x.parent) == null ? null : xp.parent; + } + if (xp != null) { + xp.red = false; + if (xpp != null) { + xpp.red = true; + root = rotateLeft(root, xpp); + } + } + } + } + } + } + + static TreeNode balanceDeletion(TreeNode root, + TreeNode x) { + for (TreeNode xp, xpl, xpr;;) { + if (x == null || x == root) + return root; + else if ((xp = x.parent) == null) { + x.red = false; + return x; + } + else if (x.red) { + x.red = false; + return root; + } + else if ((xpl = xp.left) == x) { + if ((xpr = xp.right) != null && xpr.red) { + xpr.red = false; + xp.red = true; + root = rotateLeft(root, xp); + xpr = (xp = x.parent) == null ? null : xp.right; + } + if (xpr == null) + x = xp; + else { + TreeNode sl = xpr.left, sr = xpr.right; + if ((sr == null || !sr.red) && + (sl == null || !sl.red)) { + xpr.red = true; + x = xp; + } + else { + if (sr == null || !sr.red) { + if (sl != null) + sl.red = false; + xpr.red = true; + root = rotateRight(root, xpr); + xpr = (xp = x.parent) == null ? + null : xp.right; + } + if (xpr != null) { + xpr.red = (xp == null) ? false : xp.red; + if ((sr = xpr.right) != null) + sr.red = false; + } + if (xp != null) { + xp.red = false; + root = rotateLeft(root, xp); + } + x = root; + } + } + } + else { // symmetric + if (xpl != null && xpl.red) { + xpl.red = false; + xp.red = true; + root = rotateRight(root, xp); + xpl = (xp = x.parent) == null ? null : xp.left; + } + if (xpl == null) + x = xp; + else { + TreeNode sl = xpl.left, sr = xpl.right; + if ((sl == null || !sl.red) && + (sr == null || !sr.red)) { + xpl.red = true; + x = xp; + } + else { + if (sl == null || !sl.red) { + if (sr != null) + sr.red = false; + xpl.red = true; + root = rotateLeft(root, xpl); + xpl = (xp = x.parent) == null ? + null : xp.left; + } + if (xpl != null) { + xpl.red = (xp == null) ? false : xp.red; + if ((sl = xpl.left) != null) + sl.red = false; + } + if (xp != null) { + xp.red = false; + root = rotateRight(root, xp); + } + x = root; + } + } + } + } + } + + /** + * Recursive invariant check + */ + static boolean checkInvariants(TreeNode t) { + TreeNode tp = t.parent, tl = t.left, tr = t.right, + tb = t.prev, tn = (TreeNode)t.next; + if (tb != null && tb.next != t) + return false; + if (tn != null && tn.prev != t) + return false; + if (tp != null && t != tp.left && t != tp.right) + return false; + if (tl != null && (tl.parent != t || tl.hash > t.hash)) + return false; + if (tr != null && (tr.parent != t || tr.hash < t.hash)) + return false; + if (t.red && tl != null && tl.red && tr != null && tr.red) + return false; + if (tl != null && !checkInvariants(tl)) + return false; + if (tr != null && !checkInvariants(tr)) + return false; + return true; + } + + private static final sun.misc.Unsafe U; + private static final long LOCKSTATE; + static { + try { + U = getUnsafe(); + Class k = TreeBin.class; + LOCKSTATE = U.objectFieldOffset + (k.getDeclaredField("lockState")); + } catch (Exception e) { + throw new Error(e); + } + } + } + + /* ----------------Table Traversal -------------- */ + + /** + * Encapsulates traversal for methods such as containsValue; also + * serves as a base class for other iterators and spliterators. + * + * Method advance visits once each still-valid node that was + * reachable upon iterator construction. It might miss some that + * were added to a bin after the bin was visited, which is OK wrt + * consistency guarantees. Maintaining this property in the face + * of possible ongoing resizes requires a fair amount of + * bookkeeping state that is difficult to optimize away amidst + * volatile accesses. Even so, traversal maintains reasonable + * throughput. + * + * Normally, iteration proceeds bin-by-bin traversing lists. + * However, if the table has been resized, then all future steps + * must traverse both the bin at the current index as well as at + * (index + baseSize); and so on for further resizings. To + * paranoically cope with potential sharing by users of iterators + * across threads, iteration terminates if a bounds checks fails + * for a table read. + */ + static class Traverser { + Node[] tab; // current table; updated if resized + Node next; // the next entry to use + int index; // index of bin to use next + int baseIndex; // current index of initial table + int baseLimit; // index bound for initial table + final int baseSize; // initial table size + + Traverser(Node[] tab, int size, int index, int limit) { + this.tab = tab; + this.baseSize = size; + this.baseIndex = this.index = index; + this.baseLimit = limit; + this.next = null; + } + + /** + * Advances if possible, returning next valid node, or null if none. + */ + final Node advance() { + Node e; + if ((e = next) != null) + e = e.next; + for (;;) { + Node[] t; int i, n; K ek; // must use locals in checks + if (e != null) + return next = e; + if (baseIndex >= baseLimit || (t = tab) == null || + (n = t.length) <= (i = index) || i < 0) + return next = null; + if ((e = tabAt(t, index)) != null && e.hash < 0) { + if (e instanceof ForwardingNode) { + tab = ((ForwardingNode)e).nextTable; + e = null; + continue; + } + else if (e instanceof TreeBin) + e = ((TreeBin)e).first; + else + e = null; + } + if ((index += baseSize) >= n) + index = ++baseIndex; // visit upper slots if present + } + } + } + + /** + * Base of key, value, and entry Iterators. Adds fields to + * Traverser to support iterator.remove. + */ + static class BaseIterator extends Traverser { + final ConcurrentHashMapV8 map; + Node lastReturned; + BaseIterator(Node[] tab, int size, int index, int limit, + ConcurrentHashMapV8 map) { + super(tab, size, index, limit); + this.map = map; + advance(); + } + + public final boolean hasNext() { return next != null; } + public final boolean hasMoreElements() { return next != null; } + + public final void remove() { + Node p; + if ((p = lastReturned) == null) + throw new IllegalStateException(); + lastReturned = null; + map.replaceNode(p.key, null, null); + } + } + + static final class KeyIterator extends BaseIterator + implements Iterator, Enumeration { + KeyIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMapV8 map) { + super(tab, index, size, limit, map); + } + + @Override + public final K next() { + Node p; + if ((p = next) == null) + throw new NoSuchElementException(); + K k = p.key; + lastReturned = p; + advance(); + return k; + } + + @Override + public final K nextElement() { return next(); } + } + + static final class ValueIterator extends BaseIterator + implements Iterator, Enumeration { + ValueIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMapV8 map) { + super(tab, index, size, limit, map); + } + + @Override + public final V next() { + Node p; + if ((p = next) == null) + throw new NoSuchElementException(); + V v = p.val; + lastReturned = p; + advance(); + return v; + } + + @Override + public final V nextElement() { return next(); } + } + + static final class EntryIterator extends BaseIterator + implements Iterator> { + EntryIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMapV8 map) { + super(tab, index, size, limit, map); + } + + @Override + public final Entry next() { + Node p; + if ((p = next) == null) + throw new NoSuchElementException(); + K k = p.key; + V v = p.val; + lastReturned = p; + advance(); + return new MapEntry(k, v, map); + } + } + + /** + * Exported Entry for EntryIterator + */ + static final class MapEntry implements Entry { + final K key; // non-null + V val; // non-null + final ConcurrentHashMapV8 map; + MapEntry(K key, V val, ConcurrentHashMapV8 map) { + this.key = key; + this.val = val; + this.map = map; + } + @Override + public K getKey() { return key; } + @Override + public V getValue() { return val; } + @Override + public int hashCode() { return key.hashCode() ^ val.hashCode(); } + @Override + public String toString() { return key + "=" + val; } + + @Override + public boolean equals(Object o) { + Object k, v; Entry e; + return ((o instanceof Entry) && + (k = (e = (Entry)o).getKey()) != null && + (v = e.getValue()) != null && + (k == key || k.equals(key)) && + (v == val || v.equals(val))); + } + + /** + * Sets our entry's value and writes through to the map. The + * value to return is somewhat arbitrary here. Since we do not + * necessarily track asynchronous changes, the most recent + * "previous" value could be different from what we return (or + * could even have been removed, in which case the put will + * re-establish). We do not and cannot guarantee more. + */ + @Override + public V setValue(V value) { + if (value == null) throw new NullPointerException(); + V v = val; + val = value; + map.put(key, value); + return v; + } + } + + static final class KeySpliterator extends Traverser + implements ConcurrentHashMapSpliterator { + long est; // size estimate + KeySpliterator(Node[] tab, int size, int index, int limit, + long est) { + super(tab, size, index, limit); + this.est = est; + } + + @Override + public ConcurrentHashMapSpliterator trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new KeySpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1); + } + + @Override + public void forEachRemaining(Action action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null;) + action.apply(p.key); + } + + @Override + public boolean tryAdvance(Action action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.apply(p.key); + return true; + } + + @Override + public long estimateSize() { return est; } + + } + + static final class ValueSpliterator extends Traverser + implements ConcurrentHashMapSpliterator { + long est; // size estimate + ValueSpliterator(Node[] tab, int size, int index, int limit, + long est) { + super(tab, size, index, limit); + this.est = est; + } + + @Override + public ConcurrentHashMapSpliterator trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new ValueSpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1); + } + + @Override + public void forEachRemaining(Action action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null;) + action.apply(p.val); + } + + @Override + public boolean tryAdvance(Action action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.apply(p.val); + return true; + } + + @Override + public long estimateSize() { return est; } + + } + + static final class EntrySpliterator extends Traverser + implements ConcurrentHashMapSpliterator> { + final ConcurrentHashMapV8 map; // To export MapEntry + long est; // size estimate + EntrySpliterator(Node[] tab, int size, int index, int limit, + long est, ConcurrentHashMapV8 map) { + super(tab, size, index, limit); + this.map = map; + this.est = est; + } + + @Override + public ConcurrentHashMapSpliterator> trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new EntrySpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1, map); + } + + @Override + public void forEachRemaining(Action> action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null; ) + action.apply(new MapEntry(p.key, p.val, map)); + } + + @Override + public boolean tryAdvance(Action> action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.apply(new MapEntry(p.key, p.val, map)); + return true; + } + + @Override + public long estimateSize() { return est; } + + } + + /* ----------------Views -------------- */ + + /** + * Base class for views. + */ + abstract static class CollectionView + implements Collection, Serializable { + private static final long serialVersionUID = 7249069246763182397L; + final ConcurrentHashMapV8 map; + CollectionView(ConcurrentHashMapV8 map) { this.map = map; } + + /** + * Returns the map backing this view. + * + * @return the map backing this view + */ + public ConcurrentHashMapV8 getMap() { return map; } + + /** + * Removes all of the elements from this view, by removing all + * the mappings from the map backing this view. + */ + @Override + public final void clear() { map.clear(); } + @Override + public final int size() { return map.size(); } + @Override + public final boolean isEmpty() { return map.isEmpty(); } + + // implementations below rely on concrete classes supplying these + // abstract methods + /** + * Returns a "weakly consistent" iterator that will never + * throw {@link ConcurrentModificationException}, and + * guarantees to traverse elements as they existed upon + * construction of the iterator, and may (but is not + * guaranteed to) reflect any modifications subsequent to + * construction. + */ + @Override + public abstract Iterator iterator(); + @Override + public abstract boolean contains(Object o); + @Override + public abstract boolean remove(Object o); + + private static final String oomeMsg = "Required array size too large"; + + @Override + public final Object[] toArray() { + long sz = map.mappingCount(); + if (sz > MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + int n = (int)sz; + Object[] r = new Object[n]; + int i = 0; + for (E e : this) { + if (i == n) { + if (n >= MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) + n = MAX_ARRAY_SIZE; + else + n += (n >>> 1) + 1; + r = Arrays.copyOf(r, n); + } + r[i++] = e; + } + return (i == n) ? r : Arrays.copyOf(r, i); + } + + @Override + @SuppressWarnings("unchecked") + public final T[] toArray(T[] a) { + long sz = map.mappingCount(); + if (sz > MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + int m = (int)sz; + T[] r = (a.length >= m) ? a : + (T[])java.lang.reflect.Array + .newInstance(a.getClass().getComponentType(), m); + int n = r.length; + int i = 0; + for (E e : this) { + if (i == n) { + if (n >= MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) + n = MAX_ARRAY_SIZE; + else + n += (n >>> 1) + 1; + r = Arrays.copyOf(r, n); + } + r[i++] = (T)e; + } + if (a == r && i < n) { + r[i] = null; // null-terminate + return r; + } + return (i == n) ? r : Arrays.copyOf(r, i); + } + + /** + * Returns a string representation of this collection. + * The string representation consists of the string representations + * of the collection's elements in the order they are returned by + * its iterator, enclosed in square brackets ({@code "[]"}). + * Adjacent elements are separated by the characters {@code ", "} + * (comma and space). Elements are converted to strings as by + * {@link String#valueOf(Object)}. + * + * @return a string representation of this collection + */ + @Override + public final String toString() { + StringBuilder sb = new StringBuilder(); + sb.append('['); + Iterator it = iterator(); + if (it.hasNext()) { + for (;;) { + Object e = it.next(); + sb.append(e == this ? "(this Collection)" : e); + if (!it.hasNext()) + break; + sb.append(',').append(' '); + } + } + return sb.append(']').toString(); + } + + @Override + public final boolean containsAll(Collection c) { + if (c != this) { + for (Object e : c) { + if (e == null || !contains(e)) + return false; + } + } + return true; + } + + @Override + public final boolean removeAll(Collection c) { + boolean modified = false; + for (Iterator it = iterator(); it.hasNext();) { + if (c.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + @Override + public final boolean retainAll(Collection c) { + boolean modified = false; + for (Iterator it = iterator(); it.hasNext();) { + if (!c.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + } + + /** + * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in + * which additions may optionally be enabled by mapping to a + * common value. This class cannot be directly instantiated. + * See {@link #keySet() keySet()}, + * {@link #keySet(Object) keySet(V)}, + * {@link #newKeySet() newKeySet()}, + * {@link #newKeySet(int) newKeySet(int)}. + * + * @since 1.8 + */ + public static class KeySetView extends CollectionView + implements Set, Serializable { + private static final long serialVersionUID = 7249069246763182397L; + private final V value; + KeySetView(ConcurrentHashMapV8 map, V value) { // non-public + super(map); + this.value = value; + } + + /** + * Returns the default mapped value for additions, + * or {@code null} if additions are not supported. + * + * @return the default mapped value for additions, or {@code null} + * if not supported + */ + public V getMappedValue() { return value; } + + /** + * {@inheritDoc} + * @throws NullPointerException if the specified key is null + */ + @Override + public boolean contains(Object o) { return map.containsKey(o); } + + /** + * Removes the key from this map view, by removing the key (and its + * corresponding value) from the backing map. This method does + * nothing if the key is not in the map. + * + * @param o the key to be removed from the backing map + * @return {@code true} if the backing map contained the specified key + * @throws NullPointerException if the specified key is null + */ + @Override + public boolean remove(Object o) { return map.remove(o) != null; } + + /** + * @return an iterator over the keys of the backing map + */ + @Override + public Iterator iterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + int f = (t = m.table) == null ? 0 : t.length; + return new KeyIterator(t, f, 0, f, m); + } + + /** + * Adds the specified key to this set view by mapping the key to + * the default mapped value in the backing map, if defined. + * + * @param e key to be added + * @return {@code true} if this set changed as a result of the call + * @throws NullPointerException if the specified key is null + * @throws UnsupportedOperationException if no default mapped value + * for additions was provided + */ + @Override + public boolean add(K e) { + V v; + if ((v = value) == null) + throw new UnsupportedOperationException(); + return map.putVal(e, v, true) == null; + } + + /** + * Adds all of the elements in the specified collection to this set, + * as if by calling {@link #add} on each one. + * + * @param c the elements to be inserted into this set + * @return {@code true} if this set changed as a result of the call + * @throws NullPointerException if the collection or any of its + * elements are {@code null} + * @throws UnsupportedOperationException if no default mapped value + * for additions was provided + */ + @Override + public boolean addAll(Collection c) { + boolean added = false; + V v; + if ((v = value) == null) + throw new UnsupportedOperationException(); + for (K e : c) { + if (map.putVal(e, v, true) == null) + added = true; + } + return added; + } + + @Override + public int hashCode() { + int h = 0; + for (K e : this) + h += e.hashCode(); + return h; + } + + @Override + public boolean equals(Object o) { + Set c; + return ((o instanceof Set) && + ((c = (Set)o) == this || + (containsAll(c) && c.containsAll(this)))); + } + + public ConcurrentHashMapSpliterator spliterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new KeySpliterator(t, f, 0, f, n < 0L ? 0L : n); + } + + public void forEach(Action action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.apply(p.key); + } + } + } + + /** + * A view of a ConcurrentHashMapV8 as a {@link Collection} of + * values, in which additions are disabled. This class cannot be + * directly instantiated. See {@link #values()}. + */ + static final class ValuesView extends CollectionView + implements Collection, Serializable { + private static final long serialVersionUID = 2249069246763182397L; + ValuesView(ConcurrentHashMapV8 map) { super(map); } + @Override + public final boolean contains(Object o) { + return map.containsValue(o); + } + + @Override + public final boolean remove(Object o) { + if (o != null) { + for (Iterator it = iterator(); it.hasNext();) { + if (o.equals(it.next())) { + it.remove(); + return true; + } + } + } + return false; + } + + @Override + public final Iterator iterator() { + ConcurrentHashMapV8 m = map; + Node[] t; + int f = (t = m.table) == null ? 0 : t.length; + return new ValueIterator(t, f, 0, f, m); + } + + @Override + public final boolean add(V e) { + throw new UnsupportedOperationException(); + } + @Override + public final boolean addAll(Collection c) { + throw new UnsupportedOperationException(); + } + + public ConcurrentHashMapSpliterator spliterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new ValueSpliterator(t, f, 0, f, n < 0L ? 0L : n); + } + + public void forEach(Action action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.apply(p.val); + } + } + } + + /** + * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value) + * entries. This class cannot be directly instantiated. See + * {@link #entrySet()}. + */ + static final class EntrySetView extends CollectionView> + implements Set>, Serializable { + private static final long serialVersionUID = 2249069246763182397L; + EntrySetView(ConcurrentHashMapV8 map) { super(map); } + + @Override + public boolean contains(Object o) { + Object k, v, r; Entry e; + return ((o instanceof Entry) && + (k = (e = (Entry)o).getKey()) != null && + (r = map.get(k)) != null && + (v = e.getValue()) != null && + (v == r || v.equals(r))); + } + + @Override + public boolean remove(Object o) { + Object k, v; Entry e; + return ((o instanceof Entry) && + (k = (e = (Entry)o).getKey()) != null && + (v = e.getValue()) != null && + map.remove(k, v)); + } + + /** + * @return an iterator over the entries of the backing map + */ + @Override + public Iterator> iterator() { + ConcurrentHashMapV8 m = map; + Node[] t; + int f = (t = m.table) == null ? 0 : t.length; + return new EntryIterator(t, f, 0, f, m); + } + + @Override + public boolean add(Entry e) { + return map.putVal(e.getKey(), e.getValue(), false) == null; + } + + @Override + public boolean addAll(Collection> c) { + boolean added = false; + for (Entry e : c) { + if (add(e)) + added = true; + } + return added; + } + + @Override + public final int hashCode() { + int h = 0; + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + h += p.hashCode(); + } + } + return h; + } + + @Override + public final boolean equals(Object o) { + Set c; + return ((o instanceof Set) && + ((c = (Set)o) == this || + (containsAll(c) && c.containsAll(this)))); + } + + public ConcurrentHashMapSpliterator> spliterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new EntrySpliterator(t, f, 0, f, n < 0L ? 0L : n, m); + } + + public void forEach(Action> action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.apply(new MapEntry(p.key, p.val, map)); + } + } + + } + + /* ---------------- Counters -------------- */ + + // Adapted from LongAdder and Striped64. + // See their internal docs for explanation. + + // A padded cell for distributing counts + static final class CounterCell { + volatile long p0, p1, p2, p3, p4, p5, p6; + volatile long value; + volatile long q0, q1, q2, q3, q4, q5, q6; + CounterCell(long x) { value = x; } + } + + /** + * Holder for the thread-local hash code determining which + * CounterCell to use. The code is initialized via the + * counterHashCodeGenerator, but may be moved upon collisions. + */ + static final class CounterHashCode { + int code; + } + + /** + * Generates initial value for per-thread CounterHashCodes. + */ + static final AtomicInteger counterHashCodeGenerator = new AtomicInteger(); + + /** + * Increment for counterHashCodeGenerator. See class ThreadLocal + * for explanation. + */ + static final int SEED_INCREMENT = 0x61c88647; + + /** + * Per-thread counter hash codes. Shared across all instances. + */ + static final ThreadLocal threadCounterHashCode = + new ThreadLocal(); + + + final long sumCount() { + CounterCell[] as = counterCells; CounterCell a; + long sum = baseCount; + if (as != null) { + for (int i = 0; i < as.length; ++i) { + if ((a = as[i]) != null) + sum += a.value; + } + } + return sum; + } + + // See LongAdder version for explanation + private final void fullAddCount(long x, CounterHashCode hc, + boolean wasUncontended) { + int h; + if (hc == null) { + hc = new CounterHashCode(); + int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT); + h = hc.code = (s == 0) ? 1 : s; // Avoid zero + threadCounterHashCode.set(hc); + } + else + h = hc.code; + boolean collide = false; // True if last slot nonempty + for (;;) { + CounterCell[] as; CounterCell a; int n; long v; + if ((as = counterCells) != null && (n = as.length) > 0) { + if ((a = as[(n - 1) & h]) == null) { + if (cellsBusy == 0) { // Try to attach new Cell + CounterCell r = new CounterCell(x); // Optimistic create + if (cellsBusy == 0 && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + boolean created = false; + try { // Recheck under lock + CounterCell[] rs; int m, j; + if ((rs = counterCells) != null && + (m = rs.length) > 0 && + rs[j = (m - 1) & h] == null) { + rs[j] = r; + created = true; + } + } finally { + cellsBusy = 0; + } + if (created) + break; + continue; // Slot is now non-empty + } + } + collide = false; + } + else if (!wasUncontended) // CAS already known to fail + wasUncontended = true; // Continue after rehash + else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x)) + break; + else if (counterCells != as || n >= NCPU) + collide = false; // At max size or stale + else if (!collide) + collide = true; + else if (cellsBusy == 0 && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + try { + if (counterCells == as) {// Expand table unless stale + CounterCell[] rs = new CounterCell[n << 1]; + for (int i = 0; i < n; ++i) + rs[i] = as[i]; + counterCells = rs; + } + } finally { + cellsBusy = 0; + } + collide = false; + continue; // Retry with expanded table + } + h ^= h << 13; // Rehash + h ^= h >>> 17; + h ^= h << 5; + } + else if (cellsBusy == 0 && counterCells == as && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + boolean init = false; + try { // Initialize table + if (counterCells == as) { + CounterCell[] rs = new CounterCell[2]; + rs[h & 1] = new CounterCell(x); + counterCells = rs; + init = true; + } + } finally { + cellsBusy = 0; + } + if (init) + break; + } + else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x)) + break; // Fall back on using base + } + hc.code = h; // Record index for next time + } + + // Unsafe mechanics + private static final sun.misc.Unsafe U; + private static final long SIZECTL; + private static final long TRANSFERINDEX; + private static final long TRANSFERORIGIN; + private static final long BASECOUNT; + private static final long CELLSBUSY; + private static final long CELLVALUE; + private static final long ABASE; + private static final int ASHIFT; + + static { + try { + U = getUnsafe(); + Class k = ConcurrentHashMapV8.class; + SIZECTL = U.objectFieldOffset + (k.getDeclaredField("sizeCtl")); + TRANSFERINDEX = U.objectFieldOffset + (k.getDeclaredField("transferIndex")); + TRANSFERORIGIN = U.objectFieldOffset + (k.getDeclaredField("transferOrigin")); + BASECOUNT = U.objectFieldOffset + (k.getDeclaredField("baseCount")); + CELLSBUSY = U.objectFieldOffset + (k.getDeclaredField("cellsBusy")); + Class ck = CounterCell.class; + CELLVALUE = U.objectFieldOffset + (ck.getDeclaredField("value")); + Class ak = Node[].class; + ABASE = U.arrayBaseOffset(ak); + int scale = U.arrayIndexScale(ak); + if ((scale & (scale - 1)) != 0) + throw new Error("data type scale not a power of two"); + ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); + } catch (Exception e) { + throw new Error(e); + } + } + + /** + * Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. + * Replace with a simple call to Unsafe.getUnsafe when integrating + * into a jdk. + * + * @return a sun.misc.Unsafe + */ + private static sun.misc.Unsafe getUnsafe() { + try { + return sun.misc.Unsafe.getUnsafe(); + } catch (SecurityException tryReflectionInstead) {} + try { + return java.security.AccessController.doPrivileged + (new java.security.PrivilegedExceptionAction() { + @Override + public sun.misc.Unsafe run() throws Exception { + Class k = sun.misc.Unsafe.class; + for (java.lang.reflect.Field f : k.getDeclaredFields()) { + f.setAccessible(true); + Object x = f.get(null); + if (k.isInstance(x)) + return k.cast(x); + } + throw new NoSuchFieldError("the Unsafe"); + }}); + } catch (java.security.PrivilegedActionException e) { + throw new RuntimeException("Could not initialize intrinsics", + e.getCause()); + } + } +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentLinkedHashMap.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentLinkedHashMap.java new file mode 100644 index 0000000000..cf81c29b1e --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/ConcurrentLinkedHashMap.java @@ -0,0 +1,1574 @@ +/* + * Copyright 2010 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.googlecode.concurrentlinkedhashmap; + +import static com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap.DrainStatus.IDLE; +import static com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap.DrainStatus.PROCESSING; +import static com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap.DrainStatus.REQUIRED; +import static java.util.Collections.emptyList; +import static java.util.Collections.unmodifiableMap; +import static java.util.Collections.unmodifiableSet; + +import java.io.InvalidObjectException; +import java.io.ObjectInputStream; +import java.io.Serializable; +import java.util.AbstractCollection; +import java.util.AbstractMap; +import java.util.AbstractQueue; +import java.util.AbstractSet; +import java.util.Collection; +import java.util.HashMap; +import java.util.Iterator; +import java.util.LinkedHashMap; +import java.util.LinkedHashSet; +import java.util.Map; +import java.util.Queue; +import java.util.Set; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.atomic.AtomicLong; +import java.util.concurrent.atomic.AtomicReference; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; + +/** + * A hash table supporting full concurrency of retrievals, adjustable expected + * concurrency for updates, and a maximum capacity to bound the map by. This + * implementation differs from {@link ConcurrentHashMap} in that it maintains a + * page replacement algorithm that is used to evict an entry when the map has + * exceeded its capacity. Unlike the Java Collections Framework, this + * map does not have a publicly visible constructor and instances are created + * through a {@link Builder}. + *

+ * An entry is evicted from the map when the weighted capacity exceeds + * its maximum weighted capacity threshold. A {@link EntryWeigher} + * determines how many units of capacity that an entry consumes. The default + * weigher assigns each value a weight of 1 to bound the map by the + * total number of key-value pairs. A map that holds collections may choose to + * weigh values by the number of elements in the collection and bound the map + * by the total number of elements that it contains. A change to a value that + * modifies its weight requires that an update operation is performed on the + * map. + *

+ * An {@link EvictionListener} may be supplied for notification when an entry + * is evicted from the map. This listener is invoked on a caller's thread and + * will not block other threads from operating on the map. An implementation + * should be aware that the caller's thread will not expect long execution + * times or failures as a side effect of the listener being notified. Execution + * safety and a fast turn around time can be achieved by performing the + * operation asynchronously, such as by submitting a task to an + * {@link java.util.concurrent.ExecutorService}. + *

+ * The concurrency level determines the number of threads that can + * concurrently modify the table. Using a significantly higher or lower value + * than needed can waste space or lead to thread contention, but an estimate + * within an order of magnitude of the ideal value does not usually have a + * noticeable impact. Because placement in hash tables is essentially random, + * the actual concurrency will vary. + *

+ * This class and its views and iterators implement all of the + * optional methods of the {@link Map} and {@link Iterator} + * interfaces. + *

+ * Like {@link java.util.Hashtable} but unlike {@link HashMap}, this class + * does not allow null to be used as a key or value. Unlike + * {@link LinkedHashMap}, this class does not provide + * predictable iteration order. A snapshot of the keys and entries may be + * obtained in ascending and descending order of retention. + * + * @author ben.manes@gmail.com (Ben Manes) + * @param the type of keys maintained by this map + * @param the type of mapped values + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +public final class ConcurrentLinkedHashMap extends AbstractMap + implements ConcurrentMap, Serializable { + + /* + * This class performs a best-effort bounding of a ConcurrentHashMap using a + * page-replacement algorithm to determine which entries to evict when the + * capacity is exceeded. + * + * The page replacement algorithm's data structures are kept eventually + * consistent with the map. An update to the map and recording of reads may + * not be immediately reflected on the algorithm's data structures. These + * structures are guarded by a lock and operations are applied in batches to + * avoid lock contention. The penalty of applying the batches is spread across + * threads so that the amortized cost is slightly higher than performing just + * the ConcurrentHashMap operation. + * + * A memento of the reads and writes that were performed on the map are + * recorded in buffers. These buffers are drained at the first opportunity + * after a write or when the read buffer exceeds a threshold size. The reads + * are recorded in a lossy buffer, allowing the reordering operations to be + * discarded if the draining process cannot keep up. Due to the concurrent + * nature of the read and write operations a strict policy ordering is not + * possible, but is observably strict when single threaded. + * + * Due to a lack of a strict ordering guarantee, a task can be executed + * out-of-order, such as a removal followed by its addition. The state of the + * entry is encoded within the value's weight. + * + * Alive: The entry is in both the hash-table and the page replacement policy. + * This is represented by a positive weight. + * + * Retired: The entry is not in the hash-table and is pending removal from the + * page replacement policy. This is represented by a negative weight. + * + * Dead: The entry is not in the hash-table and is not in the page replacement + * policy. This is represented by a weight of zero. + * + * The Least Recently Used page replacement algorithm was chosen due to its + * simplicity, high hit rate, and ability to be implemented with O(1) time + * complexity. + */ + + /** The number of CPUs */ + static final int NCPU = Runtime.getRuntime().availableProcessors(); + + /** The maximum weighted capacity of the map. */ + static final long MAXIMUM_CAPACITY = Long.MAX_VALUE - Integer.MAX_VALUE; + + /** The number of read buffers to use. */ + static final int NUMBER_OF_READ_BUFFERS = ceilingNextPowerOfTwo(NCPU); + + /** Mask value for indexing into the read buffers. */ + static final int READ_BUFFERS_MASK = NUMBER_OF_READ_BUFFERS - 1; + + /** The number of pending read operations before attempting to drain. */ + static final int READ_BUFFER_THRESHOLD = 32; + + /** The maximum number of read operations to perform per amortized drain. */ + static final int READ_BUFFER_DRAIN_THRESHOLD = 2 * READ_BUFFER_THRESHOLD; + + /** The maximum number of pending reads per buffer. */ + static final int READ_BUFFER_SIZE = 2 * READ_BUFFER_DRAIN_THRESHOLD; + + /** Mask value for indexing into the read buffer. */ + static final int READ_BUFFER_INDEX_MASK = READ_BUFFER_SIZE - 1; + + /** The maximum number of write operations to perform per amortized drain. */ + static final int WRITE_BUFFER_DRAIN_THRESHOLD = 16; + + /** A queue that discards all entries. */ + static final Queue DISCARDING_QUEUE = new DiscardingQueue(); + + static int ceilingNextPowerOfTwo(int x) { + // From Hacker's Delight, Chapter 3, Harry S. Warren Jr. + return 1 << (Integer.SIZE - Integer.numberOfLeadingZeros(x - 1)); + } + + // The backing data store holding the key-value associations + final ConcurrentMap> data; + final int concurrencyLevel; + + // These fields provide support to bound the map by a maximum capacity + final long[] readBufferReadCount; + final LinkedDeque> evictionDeque; + + final AtomicLong weightedSize; + final AtomicLong capacity; + + final Lock evictionLock; + final Queue writeBuffer; + final AtomicLong[] readBufferWriteCount; + final AtomicLong[] readBufferDrainAtWriteCount; + final AtomicReference>[][] readBuffers; + + final AtomicReference drainStatus; + final EntryWeigher weigher; + + // These fields provide support for notifying a listener. + final Queue> pendingNotifications; + final EvictionListener listener; + + transient Set keySet; + transient Collection values; + transient Set> entrySet; + + /** + * Creates an instance based on the builder's configuration. + */ + @SuppressWarnings({"unchecked", "cast"}) + private ConcurrentLinkedHashMap(Builder builder) { + // The data store and its maximum capacity + concurrencyLevel = builder.concurrencyLevel; + capacity = new AtomicLong(Math.min(builder.capacity, MAXIMUM_CAPACITY)); + data = new ConcurrentHashMapV8>(builder.initialCapacity, 0.75f, concurrencyLevel); + + // The eviction support + weigher = builder.weigher; + evictionLock = new ReentrantLock(); + weightedSize = new AtomicLong(); + evictionDeque = new LinkedDeque>(); + writeBuffer = new ConcurrentLinkedQueue(); + drainStatus = new AtomicReference(IDLE); + + readBufferReadCount = new long[NUMBER_OF_READ_BUFFERS]; + readBufferWriteCount = new AtomicLong[NUMBER_OF_READ_BUFFERS]; + readBufferDrainAtWriteCount = new AtomicLong[NUMBER_OF_READ_BUFFERS]; + readBuffers = new AtomicReference[NUMBER_OF_READ_BUFFERS][READ_BUFFER_SIZE]; + for (int i = 0; i < NUMBER_OF_READ_BUFFERS; i++) { + readBufferWriteCount[i] = new AtomicLong(); + readBufferDrainAtWriteCount[i] = new AtomicLong(); + readBuffers[i] = new AtomicReference[READ_BUFFER_SIZE]; + for (int j = 0; j < READ_BUFFER_SIZE; j++) { + readBuffers[i][j] = new AtomicReference>(); + } + } + + // The notification queue and listener + listener = builder.listener; + pendingNotifications = (listener == DiscardingListener.INSTANCE) + ? (Queue>) DISCARDING_QUEUE + : new ConcurrentLinkedQueue>(); + } + + /** Ensures that the object is not null. */ + static void checkNotNull(Object o) { + if (o == null) { + throw new NullPointerException(); + } + } + + /** Ensures that the argument expression is true. */ + static void checkArgument(boolean expression) { + if (!expression) { + throw new IllegalArgumentException(); + } + } + + /** Ensures that the state expression is true. */ + static void checkState(boolean expression) { + if (!expression) { + throw new IllegalStateException(); + } + } + + /* ---------------- Eviction Support -------------- */ + + /** + * Retrieves the maximum weighted capacity of the map. + * + * @return the maximum weighted capacity + */ + public long capacity() { + return capacity.get(); + } + + /** + * Sets the maximum weighted capacity of the map and eagerly evicts entries + * until it shrinks to the appropriate size. + * + * @param capacity the maximum weighted capacity of the map + * @throws IllegalArgumentException if the capacity is negative + */ + public void setCapacity(long capacity) { + checkArgument(capacity >= 0); + evictionLock.lock(); + try { + this.capacity.lazySet(Math.min(capacity, MAXIMUM_CAPACITY)); + drainBuffers(); + evict(); + } finally { + evictionLock.unlock(); + } + notifyListener(); + } + + /** Determines whether the map has exceeded its capacity. */ + boolean hasOverflowed() { + return weightedSize.get() > capacity.get(); + } + + /** + * Evicts entries from the map while it exceeds the capacity and appends + * evicted entries to the notification queue for processing. + */ + void evict() { + // Attempts to evict entries from the map if it exceeds the maximum + // capacity. If the eviction fails due to a concurrent removal of the + // victim, that removal may cancel out the addition that triggered this + // eviction. The victim is eagerly unlinked before the removal task so + // that if an eviction is still required then a new victim will be chosen + // for removal. + while (hasOverflowed()) { + final Node node = evictionDeque.poll(); + + // If weighted values are used, then the pending operations will adjust + // the size to reflect the correct weight + if (node == null) { + return; + } + + // Notify the listener only if the entry was evicted + if (data.remove(node.key, node)) { + pendingNotifications.add(node); + } + + makeDead(node); + } + } + + /** + * Performs the post-processing work required after a read. + * + * @param node the entry in the page replacement policy + */ + void afterRead(Node node) { + final int bufferIndex = readBufferIndex(); + final long writeCount = recordRead(bufferIndex, node); + drainOnReadIfNeeded(bufferIndex, writeCount); + notifyListener(); + } + + /** Returns the index to the read buffer to record into. */ + static int readBufferIndex() { + // A buffer is chosen by the thread's id so that tasks are distributed in a + // pseudo evenly manner. This helps avoid hot entries causing contention + // due to other threads trying to append to the same buffer. + return ((int) Thread.currentThread().getId()) & READ_BUFFERS_MASK; + } + + /** + * Records a read in the buffer and return its write count. + * + * @param bufferIndex the index to the chosen read buffer + * @param node the entry in the page replacement policy + * @return the number of writes on the chosen read buffer + */ + long recordRead(int bufferIndex, Node node) { + // The location in the buffer is chosen in a racy fashion as the increment + // is not atomic with the insertion. This means that concurrent reads can + // overlap and overwrite one another, resulting in a lossy buffer. + final AtomicLong counter = readBufferWriteCount[bufferIndex]; + final long writeCount = counter.get(); + counter.lazySet(writeCount + 1); + + final int index = (int) (writeCount & READ_BUFFER_INDEX_MASK); + readBuffers[bufferIndex][index].lazySet(node); + + return writeCount; + } + + /** + * Attempts to drain the buffers if it is determined to be needed when + * post-processing a read. + * + * @param bufferIndex the index to the chosen read buffer + * @param writeCount the number of writes on the chosen read buffer + */ + void drainOnReadIfNeeded(int bufferIndex, long writeCount) { + final long pending = (writeCount - readBufferDrainAtWriteCount[bufferIndex].get()); + final boolean delayable = (pending < READ_BUFFER_THRESHOLD); + final DrainStatus status = drainStatus.get(); + if (status.shouldDrainBuffers(delayable)) { + tryToDrainBuffers(); + } + } + + /** + * Performs the post-processing work required after a write. + * + * @param task the pending operation to be applied + */ + void afterWrite(Runnable task) { + writeBuffer.add(task); + drainStatus.lazySet(REQUIRED); + tryToDrainBuffers(); + notifyListener(); + } + + /** + * Attempts to acquire the eviction lock and apply the pending operations, up + * to the amortized threshold, to the page replacement policy. + */ + void tryToDrainBuffers() { + if (evictionLock.tryLock()) { + try { + drainStatus.lazySet(PROCESSING); + drainBuffers(); + } finally { + drainStatus.compareAndSet(PROCESSING, IDLE); + evictionLock.unlock(); + } + } + } + + /** Drains the read and write buffers up to an amortized threshold. */ + void drainBuffers() { + drainReadBuffers(); + drainWriteBuffer(); + } + + /** Drains the read buffers, each up to an amortized threshold. */ + void drainReadBuffers() { + final int start = (int) Thread.currentThread().getId(); + final int end = start + NUMBER_OF_READ_BUFFERS; + for (int i = start; i < end; i++) { + drainReadBuffer(i & READ_BUFFERS_MASK); + } + } + + /** Drains the read buffer up to an amortized threshold. */ + void drainReadBuffer(int bufferIndex) { + final long writeCount = readBufferWriteCount[bufferIndex].get(); + for (int i = 0; i < READ_BUFFER_DRAIN_THRESHOLD; i++) { + final int index = (int) (readBufferReadCount[bufferIndex] & READ_BUFFER_INDEX_MASK); + final AtomicReference> slot = readBuffers[bufferIndex][index]; + final Node node = slot.get(); + if (node == null) { + break; + } + + slot.lazySet(null); + applyRead(node); + readBufferReadCount[bufferIndex]++; + } + readBufferDrainAtWriteCount[bufferIndex].lazySet(writeCount); + } + + /** Updates the node's location in the page replacement policy. */ + void applyRead(Node node) { + // An entry may be scheduled for reordering despite having been removed. + // This can occur when the entry was concurrently read while a writer was + // removing it. If the entry is no longer linked then it does not need to + // be processed. + if (evictionDeque.contains(node)) { + evictionDeque.moveToBack(node); + } + } + + /** Drains the read buffer up to an amortized threshold. */ + void drainWriteBuffer() { + for (int i = 0; i < WRITE_BUFFER_DRAIN_THRESHOLD; i++) { + final Runnable task = writeBuffer.poll(); + if (task == null) { + break; + } + task.run(); + } + } + + /** + * Attempts to transition the node from the alive state to the + * retired state. + * + * @param node the entry in the page replacement policy + * @param expect the expected weighted value + * @return if successful + */ + boolean tryToRetire(Node node, WeightedValue expect) { + if (expect.isAlive()) { + final WeightedValue retired = new WeightedValue(expect.value, -expect.weight); + return node.compareAndSet(expect, retired); + } + return false; + } + + /** + * Atomically transitions the node from the alive state to the + * retired state, if a valid transition. + * + * @param node the entry in the page replacement policy + */ + void makeRetired(Node node) { + for (;;) { + final WeightedValue current = node.get(); + if (!current.isAlive()) { + return; + } + final WeightedValue retired = new WeightedValue(current.value, -current.weight); + if (node.compareAndSet(current, retired)) { + return; + } + } + } + + /** + * Atomically transitions the node to the dead state and decrements + * the weightedSize. + * + * @param node the entry in the page replacement policy + */ + void makeDead(Node node) { + for (;;) { + WeightedValue current = node.get(); + WeightedValue dead = new WeightedValue(current.value, 0); + if (node.compareAndSet(current, dead)) { + weightedSize.lazySet(weightedSize.get() - Math.abs(current.weight)); + return; + } + } + } + + /** Notifies the listener of entries that were evicted. */ + void notifyListener() { + Node node; + while ((node = pendingNotifications.poll()) != null) { + listener.onEviction(node.key, node.getValue()); + } + } + + /** Adds the node to the page replacement policy. */ + final class AddTask implements Runnable { + final Node node; + final int weight; + + AddTask(Node node, int weight) { + this.weight = weight; + this.node = node; + } + + @Override + public void run() { + weightedSize.lazySet(weightedSize.get() + weight); + + // ignore out-of-order write operations + if (node.get().isAlive()) { + evictionDeque.add(node); + evict(); + } + } + } + + /** Removes a node from the page replacement policy. */ + final class RemovalTask implements Runnable { + final Node node; + + RemovalTask(Node node) { + this.node = node; + } + + @Override + public void run() { + // add may not have been processed yet + evictionDeque.remove(node); + makeDead(node); + } + } + + /** Updates the weighted size and evicts an entry on overflow. */ + final class UpdateTask implements Runnable { + final int weightDifference; + final Node node; + + public UpdateTask(Node node, int weightDifference) { + this.weightDifference = weightDifference; + this.node = node; + } + + @Override + public void run() { + weightedSize.lazySet(weightedSize.get() + weightDifference); + applyRead(node); + evict(); + } + } + + /* ---------------- Concurrent Map Support -------------- */ + + @Override + public boolean isEmpty() { + return data.isEmpty(); + } + + @Override + public int size() { + return data.size(); + } + + /** + * Returns the weighted size of this map. + * + * @return the combined weight of the values in this map + */ + public long weightedSize() { + return Math.max(0, weightedSize.get()); + } + + @Override + public void clear() { + evictionLock.lock(); + try { + // Discard all entries + Node node; + while ((node = evictionDeque.poll()) != null) { + data.remove(node.key, node); + makeDead(node); + } + + // Discard all pending reads + for (AtomicReference>[] buffer : readBuffers) { + for (AtomicReference> slot : buffer) { + slot.lazySet(null); + } + } + + // Apply all pending writes + Runnable task; + while ((task = writeBuffer.poll()) != null) { + task.run(); + } + } finally { + evictionLock.unlock(); + } + } + + @Override + public boolean containsKey(Object key) { + return data.containsKey(key); + } + + @Override + public boolean containsValue(Object value) { + checkNotNull(value); + + for (Node node : data.values()) { + if (node.getValue().equals(value)) { + return true; + } + } + return false; + } + + @Override + public V get(Object key) { + final Node node = data.get(key); + if (node == null) { + return null; + } + afterRead(node); + return node.getValue(); + } + + /** + * Returns the value to which the specified key is mapped, or {@code null} + * if this map contains no mapping for the key. This method differs from + * {@link #get(Object)} in that it does not record the operation with the + * page replacement policy. + * + * @param key the key whose associated value is to be returned + * @return the value to which the specified key is mapped, or + * {@code null} if this map contains no mapping for the key + * @throws NullPointerException if the specified key is null + */ + public V getQuietly(Object key) { + final Node node = data.get(key); + return (node == null) ? null : node.getValue(); + } + + @Override + public V put(K key, V value) { + return put(key, value, false); + } + + @Override + public V putIfAbsent(K key, V value) { + return put(key, value, true); + } + + /** + * Adds a node to the list and the data store. If an existing node is found, + * then its value is updated if allowed. + * + * @param key key with which the specified value is to be associated + * @param value value to be associated with the specified key + * @param onlyIfAbsent a write is performed only if the key is not already + * associated with a value + * @return the prior value in the data store or null if no mapping was found + */ + V put(K key, V value, boolean onlyIfAbsent) { + checkNotNull(key); + checkNotNull(value); + + final int weight = weigher.weightOf(key, value); + final WeightedValue weightedValue = new WeightedValue(value, weight); + final Node node = new Node(key, weightedValue); + + for (;;) { + final Node prior = data.putIfAbsent(node.key, node); + if (prior == null) { + afterWrite(new AddTask(node, weight)); + return null; + } else if (onlyIfAbsent) { + afterRead(prior); + return prior.getValue(); + } + for (;;) { + final WeightedValue oldWeightedValue = prior.get(); + if (!oldWeightedValue.isAlive()) { + break; + } + + if (prior.compareAndSet(oldWeightedValue, weightedValue)) { + final int weightedDifference = weight - oldWeightedValue.weight; + if (weightedDifference == 0) { + afterRead(prior); + } else { + afterWrite(new UpdateTask(prior, weightedDifference)); + } + return oldWeightedValue.value; + } + } + } + } + + @Override + public V remove(Object key) { + final Node node = data.remove(key); + if (node == null) { + return null; + } + + makeRetired(node); + afterWrite(new RemovalTask(node)); + return node.getValue(); + } + + @Override + public boolean remove(Object key, Object value) { + final Node node = data.get(key); + if ((node == null) || (value == null)) { + return false; + } + + WeightedValue weightedValue = node.get(); + for (;;) { + if (weightedValue.contains(value)) { + if (tryToRetire(node, weightedValue)) { + if (data.remove(key, node)) { + afterWrite(new RemovalTask(node)); + return true; + } + } else { + weightedValue = node.get(); + if (weightedValue.isAlive()) { + // retry as an intermediate update may have replaced the value with + // an equal instance that has a different reference identity + continue; + } + } + } + return false; + } + } + + @Override + public V replace(K key, V value) { + checkNotNull(key); + checkNotNull(value); + + final int weight = weigher.weightOf(key, value); + final WeightedValue weightedValue = new WeightedValue(value, weight); + + final Node node = data.get(key); + if (node == null) { + return null; + } + for (;;) { + final WeightedValue oldWeightedValue = node.get(); + if (!oldWeightedValue.isAlive()) { + return null; + } + if (node.compareAndSet(oldWeightedValue, weightedValue)) { + final int weightedDifference = weight - oldWeightedValue.weight; + if (weightedDifference == 0) { + afterRead(node); + } else { + afterWrite(new UpdateTask(node, weightedDifference)); + } + return oldWeightedValue.value; + } + } + } + + @Override + public boolean replace(K key, V oldValue, V newValue) { + checkNotNull(key); + checkNotNull(oldValue); + checkNotNull(newValue); + + final int weight = weigher.weightOf(key, newValue); + final WeightedValue newWeightedValue = new WeightedValue(newValue, weight); + + final Node node = data.get(key); + if (node == null) { + return false; + } + for (;;) { + final WeightedValue weightedValue = node.get(); + if (!weightedValue.isAlive() || !weightedValue.contains(oldValue)) { + return false; + } + if (node.compareAndSet(weightedValue, newWeightedValue)) { + final int weightedDifference = weight - weightedValue.weight; + if (weightedDifference == 0) { + afterRead(node); + } else { + afterWrite(new UpdateTask(node, weightedDifference)); + } + return true; + } + } + } + + @Override + public Set keySet() { + final Set ks = keySet; + return (ks == null) ? (keySet = new KeySet()) : ks; + } + + /** + * Returns a unmodifiable snapshot {@link Set} view of the keys contained in + * this map. The set's iterator returns the keys whose order of iteration is + * the ascending order in which its entries are considered eligible for + * retention, from the least-likely to be retained to the most-likely. + *

+ * Beware that, unlike in {@link #keySet()}, obtaining the set is NOT + * a constant-time operation. Because of the asynchronous nature of the page + * replacement policy, determining the retention ordering requires a traversal + * of the keys. + * + * @return an ascending snapshot view of the keys in this map + */ + public Set ascendingKeySet() { + return ascendingKeySetWithLimit(Integer.MAX_VALUE); + } + + /** + * Returns an unmodifiable snapshot {@link Set} view of the keys contained in + * this map. The set's iterator returns the keys whose order of iteration is + * the ascending order in which its entries are considered eligible for + * retention, from the least-likely to be retained to the most-likely. + *

+ * Beware that, unlike in {@link #keySet()}, obtaining the set is NOT + * a constant-time operation. Because of the asynchronous nature of the page + * replacement policy, determining the retention ordering requires a traversal + * of the keys. + * + * @param limit the maximum size of the returned set + * @return a ascending snapshot view of the keys in this map + * @throws IllegalArgumentException if the limit is negative + */ + public Set ascendingKeySetWithLimit(int limit) { + return orderedKeySet(true, limit); + } + + /** + * Returns an unmodifiable snapshot {@link Set} view of the keys contained in + * this map. The set's iterator returns the keys whose order of iteration is + * the descending order in which its entries are considered eligible for + * retention, from the most-likely to be retained to the least-likely. + *

+ * Beware that, unlike in {@link #keySet()}, obtaining the set is NOT + * a constant-time operation. Because of the asynchronous nature of the page + * replacement policy, determining the retention ordering requires a traversal + * of the keys. + * + * @return a descending snapshot view of the keys in this map + */ + public Set descendingKeySet() { + return descendingKeySetWithLimit(Integer.MAX_VALUE); + } + + /** + * Returns an unmodifiable snapshot {@link Set} view of the keys contained in + * this map. The set's iterator returns the keys whose order of iteration is + * the descending order in which its entries are considered eligible for + * retention, from the most-likely to be retained to the least-likely. + *

+ * Beware that, unlike in {@link #keySet()}, obtaining the set is NOT + * a constant-time operation. Because of the asynchronous nature of the page + * replacement policy, determining the retention ordering requires a traversal + * of the keys. + * + * @param limit the maximum size of the returned set + * @return a descending snapshot view of the keys in this map + * @throws IllegalArgumentException if the limit is negative + */ + public Set descendingKeySetWithLimit(int limit) { + return orderedKeySet(false, limit); + } + + Set orderedKeySet(boolean ascending, int limit) { + checkArgument(limit >= 0); + evictionLock.lock(); + try { + drainBuffers(); + + final int initialCapacity = (weigher == Weighers.entrySingleton()) + ? Math.min(limit, (int) weightedSize()) + : 16; + final Set keys = new LinkedHashSet(initialCapacity); + final Iterator> iterator = ascending + ? evictionDeque.iterator() + : evictionDeque.descendingIterator(); + while (iterator.hasNext() && (limit > keys.size())) { + keys.add(iterator.next().key); + } + return unmodifiableSet(keys); + } finally { + evictionLock.unlock(); + } + } + + @Override + public Collection values() { + final Collection vs = values; + return (vs == null) ? (values = new Values()) : vs; + } + + @Override + public Set> entrySet() { + final Set> es = entrySet; + return (es == null) ? (entrySet = new EntrySet()) : es; + } + + /** + * Returns an unmodifiable snapshot {@link Map} view of the mappings contained + * in this map. The map's collections return the mappings whose order of + * iteration is the ascending order in which its entries are considered + * eligible for retention, from the least-likely to be retained to the + * most-likely. + *

+ * Beware that obtaining the mappings is NOT a constant-time + * operation. Because of the asynchronous nature of the page replacement + * policy, determining the retention ordering requires a traversal of the + * entries. + * + * @return a ascending snapshot view of this map + */ + public Map ascendingMap() { + return ascendingMapWithLimit(Integer.MAX_VALUE); + } + + /** + * Returns an unmodifiable snapshot {@link Map} view of the mappings contained + * in this map. The map's collections return the mappings whose order of + * iteration is the ascending order in which its entries are considered + * eligible for retention, from the least-likely to be retained to the + * most-likely. + *

+ * Beware that obtaining the mappings is NOT a constant-time + * operation. Because of the asynchronous nature of the page replacement + * policy, determining the retention ordering requires a traversal of the + * entries. + * + * @param limit the maximum size of the returned map + * @return a ascending snapshot view of this map + * @throws IllegalArgumentException if the limit is negative + */ + public Map ascendingMapWithLimit(int limit) { + return orderedMap(true, limit); + } + + /** + * Returns an unmodifiable snapshot {@link Map} view of the mappings contained + * in this map. The map's collections return the mappings whose order of + * iteration is the descending order in which its entries are considered + * eligible for retention, from the most-likely to be retained to the + * least-likely. + *

+ * Beware that obtaining the mappings is NOT a constant-time + * operation. Because of the asynchronous nature of the page replacement + * policy, determining the retention ordering requires a traversal of the + * entries. + * + * @return a descending snapshot view of this map + */ + public Map descendingMap() { + return descendingMapWithLimit(Integer.MAX_VALUE); + } + + /** + * Returns an unmodifiable snapshot {@link Map} view of the mappings contained + * in this map. The map's collections return the mappings whose order of + * iteration is the descending order in which its entries are considered + * eligible for retention, from the most-likely to be retained to the + * least-likely. + *

+ * Beware that obtaining the mappings is NOT a constant-time + * operation. Because of the asynchronous nature of the page replacement + * policy, determining the retention ordering requires a traversal of the + * entries. + * + * @param limit the maximum size of the returned map + * @return a descending snapshot view of this map + * @throws IllegalArgumentException if the limit is negative + */ + public Map descendingMapWithLimit(int limit) { + return orderedMap(false, limit); + } + + Map orderedMap(boolean ascending, int limit) { + checkArgument(limit >= 0); + evictionLock.lock(); + try { + drainBuffers(); + + final int initialCapacity = (weigher == Weighers.entrySingleton()) + ? Math.min(limit, (int) weightedSize()) + : 16; + final Map map = new LinkedHashMap(initialCapacity); + final Iterator> iterator = ascending + ? evictionDeque.iterator() + : evictionDeque.descendingIterator(); + while (iterator.hasNext() && (limit > map.size())) { + Node node = iterator.next(); + map.put(node.key, node.getValue()); + } + return unmodifiableMap(map); + } finally { + evictionLock.unlock(); + } + } + + /** The draining status of the buffers. */ + enum DrainStatus { + + /** A drain is not taking place. */ + IDLE { + @Override boolean shouldDrainBuffers(boolean delayable) { + return !delayable; + } + }, + + /** A drain is required due to a pending write modification. */ + REQUIRED { + @Override boolean shouldDrainBuffers(boolean delayable) { + return true; + } + }, + + /** A drain is in progress. */ + PROCESSING { + @Override boolean shouldDrainBuffers(boolean delayable) { + return false; + } + }; + + /** + * Determines whether the buffers should be drained. + * + * @param delayable if a drain should be delayed until required + * @return if a drain should be attempted + */ + abstract boolean shouldDrainBuffers(boolean delayable); + } + + /** A value, its weight, and the entry's status. */ + static final class WeightedValue { + final int weight; + final V value; + + WeightedValue(V value, int weight) { + this.weight = weight; + this.value = value; + } + + boolean contains(Object o) { + return (o == value) || value.equals(o); + } + + /** + * If the entry is available in the hash-table and page replacement policy. + */ + boolean isAlive() { + return weight > 0; + } + + /** + * If the entry was removed from the hash-table and is awaiting removal from + * the page replacement policy. + */ + boolean isRetired() { + return weight < 0; + } + + /** + * If the entry was removed from the hash-table and the page replacement + * policy. + */ + boolean isDead() { + return weight == 0; + } + } + + /** + * A node contains the key, the weighted value, and the linkage pointers on + * the page-replacement algorithm's data structures. + */ + @SuppressWarnings("serial") + static final class Node extends AtomicReference> + implements Linked> { + final K key; + Node prev; + Node next; + + /** Creates a new, unlinked node. */ + Node(K key, WeightedValue weightedValue) { + super(weightedValue); + this.key = key; + } + + @Override + public Node getPrevious() { + return prev; + } + + @Override + public void setPrevious(Node prev) { + this.prev = prev; + } + + @Override + public Node getNext() { + return next; + } + + @Override + public void setNext(Node next) { + this.next = next; + } + + /** Retrieves the value held by the current WeightedValue. */ + V getValue() { + return get().value; + } + } + + /** An adapter to safely externalize the keys. */ + final class KeySet extends AbstractSet { + final ConcurrentLinkedHashMap map = ConcurrentLinkedHashMap.this; + + @Override + public int size() { + return map.size(); + } + + @Override + public void clear() { + map.clear(); + } + + @Override + public Iterator iterator() { + return new KeyIterator(); + } + + @Override + public boolean contains(Object obj) { + return containsKey(obj); + } + + @Override + public boolean remove(Object obj) { + return (map.remove(obj) != null); + } + + @Override + public Object[] toArray() { + return map.data.keySet().toArray(); + } + + @Override + public T[] toArray(T[] array) { + return map.data.keySet().toArray(array); + } + } + + /** An adapter to safely externalize the key iterator. */ + final class KeyIterator implements Iterator { + final Iterator iterator = data.keySet().iterator(); + K current; + + @Override + public boolean hasNext() { + return iterator.hasNext(); + } + + @Override + public K next() { + current = iterator.next(); + return current; + } + + @Override + public void remove() { + checkState(current != null); + ConcurrentLinkedHashMap.this.remove(current); + current = null; + } + } + + /** An adapter to safely externalize the values. */ + final class Values extends AbstractCollection { + + @Override + public int size() { + return ConcurrentLinkedHashMap.this.size(); + } + + @Override + public void clear() { + ConcurrentLinkedHashMap.this.clear(); + } + + @Override + public Iterator iterator() { + return new ValueIterator(); + } + + @Override + public boolean contains(Object o) { + return containsValue(o); + } + } + + /** An adapter to safely externalize the value iterator. */ + final class ValueIterator implements Iterator { + final Iterator> iterator = data.values().iterator(); + Node current; + + @Override + public boolean hasNext() { + return iterator.hasNext(); + } + + @Override + public V next() { + current = iterator.next(); + return current.getValue(); + } + + @Override + public void remove() { + checkState(current != null); + ConcurrentLinkedHashMap.this.remove(current.key); + current = null; + } + } + + /** An adapter to safely externalize the entries. */ + final class EntrySet extends AbstractSet> { + final ConcurrentLinkedHashMap map = ConcurrentLinkedHashMap.this; + + @Override + public int size() { + return map.size(); + } + + @Override + public void clear() { + map.clear(); + } + + @Override + public Iterator> iterator() { + return new EntryIterator(); + } + + @Override + public boolean contains(Object obj) { + if (!(obj instanceof Entry)) { + return false; + } + Entry entry = (Entry) obj; + Node node = map.data.get(entry.getKey()); + return (node != null) && (node.getValue().equals(entry.getValue())); + } + + @Override + public boolean add(Entry entry) { + return (map.putIfAbsent(entry.getKey(), entry.getValue()) == null); + } + + @Override + public boolean remove(Object obj) { + if (!(obj instanceof Entry)) { + return false; + } + Entry entry = (Entry) obj; + return map.remove(entry.getKey(), entry.getValue()); + } + } + + /** An adapter to safely externalize the entry iterator. */ + final class EntryIterator implements Iterator> { + final Iterator> iterator = data.values().iterator(); + Node current; + + @Override + public boolean hasNext() { + return iterator.hasNext(); + } + + @Override + public Entry next() { + current = iterator.next(); + return new WriteThroughEntry(current); + } + + @Override + public void remove() { + checkState(current != null); + ConcurrentLinkedHashMap.this.remove(current.key); + current = null; + } + } + + /** An entry that allows updates to write through to the map. */ + final class WriteThroughEntry extends SimpleEntry { + static final long serialVersionUID = 1; + + WriteThroughEntry(Node node) { + super(node.key, node.getValue()); + } + + @Override + public V setValue(V value) { + put(getKey(), value); + return super.setValue(value); + } + + Object writeReplace() { + return new SimpleEntry(this); + } + } + + /** A weigher that enforces that the weight falls within a valid range. */ + static final class BoundedEntryWeigher implements EntryWeigher, Serializable { + static final long serialVersionUID = 1; + final EntryWeigher weigher; + + BoundedEntryWeigher(EntryWeigher weigher) { + checkNotNull(weigher); + this.weigher = weigher; + } + + @Override + public int weightOf(K key, V value) { + int weight = weigher.weightOf(key, value); + checkArgument(weight >= 1); + return weight; + } + + Object writeReplace() { + return weigher; + } + } + + /** A queue that discards all additions and is always empty. */ + static final class DiscardingQueue extends AbstractQueue { + @Override public boolean add(Object e) { return true; } + @Override public boolean offer(Object e) { return true; } + @Override public Object poll() { return null; } + @Override public Object peek() { return null; } + @Override public int size() { return 0; } + @Override public Iterator iterator() { return emptyList().iterator(); } + } + + /** A listener that ignores all notifications. */ + enum DiscardingListener implements EvictionListener { + INSTANCE; + + @Override public void onEviction(Object key, Object value) {} + } + + /* ---------------- Serialization Support -------------- */ + + static final long serialVersionUID = 1; + + Object writeReplace() { + return new SerializationProxy(this); + } + + private void readObject(ObjectInputStream stream) throws InvalidObjectException { + throw new InvalidObjectException("Proxy required"); + } + + /** + * A proxy that is serialized instead of the map. The page-replacement + * algorithm's data structures are not serialized so the deserialized + * instance contains only the entries. This is acceptable as caches hold + * transient data that is recomputable and serialization would tend to be + * used as a fast warm-up process. + */ + static final class SerializationProxy implements Serializable { + final EntryWeigher weigher; + final EvictionListener listener; + final int concurrencyLevel; + final Map data; + final long capacity; + + SerializationProxy(ConcurrentLinkedHashMap map) { + concurrencyLevel = map.concurrencyLevel; + data = new HashMap(map); + capacity = map.capacity.get(); + listener = map.listener; + weigher = map.weigher; + } + + Object readResolve() { + ConcurrentLinkedHashMap map = new Builder() + .concurrencyLevel(concurrencyLevel) + .maximumWeightedCapacity(capacity) + .listener(listener) + .weigher(weigher) + .build(); + map.putAll(data); + return map; + } + + static final long serialVersionUID = 1; + } + + /* ---------------- Builder -------------- */ + + /** + * A builder that creates {@link ConcurrentLinkedHashMap} instances. It + * provides a flexible approach for constructing customized instances with + * a named parameter syntax. It can be used in the following manner: + * 
{@code
+   * ConcurrentMap> graph = new Builder>()
+   *     .maximumWeightedCapacity(5000)
+   *     .weigher(Weighers.set())
+   *     .build();
+   * }
+ */ + public static final class Builder { + static final int DEFAULT_CONCURRENCY_LEVEL = 16; + static final int DEFAULT_INITIAL_CAPACITY = 16; + + EvictionListener listener; + EntryWeigher weigher; + + int concurrencyLevel; + int initialCapacity; + long capacity; + + @SuppressWarnings("unchecked") + public Builder() { + capacity = -1; + weigher = Weighers.entrySingleton(); + initialCapacity = DEFAULT_INITIAL_CAPACITY; + concurrencyLevel = DEFAULT_CONCURRENCY_LEVEL; + listener = (EvictionListener) DiscardingListener.INSTANCE; + } + + /** + * Specifies the initial capacity of the hash table (default 16). + * This is the number of key-value pairs that the hash table can hold + * before a resize operation is required. + * + * @param initialCapacity the initial capacity used to size the hash table + * to accommodate this many entries. + * @throws IllegalArgumentException if the initialCapacity is negative + */ + public Builder initialCapacity(int initialCapacity) { + checkArgument(initialCapacity >= 0); + this.initialCapacity = initialCapacity; + return this; + } + + /** + * Specifies the maximum weighted capacity to coerce the map to and may + * exceed it temporarily. + * + * @param capacity the weighted threshold to bound the map by + * @throws IllegalArgumentException if the maximumWeightedCapacity is + * negative + */ + public Builder maximumWeightedCapacity(long capacity) { + checkArgument(capacity >= 0); + this.capacity = capacity; + return this; + } + + /** + * Specifies the estimated number of concurrently updating threads. The + * implementation performs internal sizing to try to accommodate this many + * threads (default 16). + * + * @param concurrencyLevel the estimated number of concurrently updating + * threads + * @throws IllegalArgumentException if the concurrencyLevel is less than or + * equal to zero + */ + public Builder concurrencyLevel(int concurrencyLevel) { + checkArgument(concurrencyLevel > 0); + this.concurrencyLevel = concurrencyLevel; + return this; + } + + /** + * Specifies an optional listener that is registered for notification when + * an entry is evicted. + * + * @param listener the object to forward evicted entries to + * @throws NullPointerException if the listener is null + */ + public Builder listener(EvictionListener listener) { + checkNotNull(listener); + this.listener = listener; + return this; + } + + /** + * Specifies an algorithm to determine how many the units of capacity a + * value consumes. The default algorithm bounds the map by the number of + * key-value pairs by giving each entry a weight of 1. + * + * @param weigher the algorithm to determine a value's weight + * @throws NullPointerException if the weigher is null + */ + public Builder weigher(Weigher weigher) { + this.weigher = (weigher == Weighers.singleton()) + ? Weighers.entrySingleton() + : new BoundedEntryWeigher(Weighers.asEntryWeigher(weigher)); + return this; + } + + /** + * Specifies an algorithm to determine how many the units of capacity an + * entry consumes. The default algorithm bounds the map by the number of + * key-value pairs by giving each entry a weight of 1. + * + * @param weigher the algorithm to determine a entry's weight + * @throws NullPointerException if the weigher is null + */ + public Builder weigher(EntryWeigher weigher) { + this.weigher = (weigher == Weighers.entrySingleton()) + ? Weighers.entrySingleton() + : new BoundedEntryWeigher(weigher); + return this; + } + + /** + * Creates a new {@link ConcurrentLinkedHashMap} instance. + * + * @throws IllegalStateException if the maximum weighted capacity was + * not set + */ + public ConcurrentLinkedHashMap build() { + checkState(capacity >= 0); + return new ConcurrentLinkedHashMap(this); + } + } +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EntryWeigher.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EntryWeigher.java new file mode 100644 index 0000000000..d07423c2e7 --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EntryWeigher.java @@ -0,0 +1,37 @@ +/* + * Copyright 2012 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.googlecode.concurrentlinkedhashmap; + +/** + * A class that can determine the weight of an entry. The total weight threshold + * is used to determine when an eviction is required. + * + * @author ben.manes@gmail.com (Ben Manes) + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +public interface EntryWeigher { + + /** + * Measures an entry's weight to determine how many units of capacity that + * the key and value consumes. An entry must consume a minimum of one unit. + * + * @param key the key to weigh + * @param value the value to weigh + * @return the entry's weight + */ + int weightOf(K key, V value); +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EvictionListener.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EvictionListener.java new file mode 100644 index 0000000000..6b3ac196d1 --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/EvictionListener.java @@ -0,0 +1,45 @@ +/* + * Copyright 2010 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.googlecode.concurrentlinkedhashmap; + +/** + * A listener registered for notification when an entry is evicted. An instance + * may be called concurrently by multiple threads to process entries. An + * implementation should avoid performing blocking calls or synchronizing on + * shared resources. + *

+ * The listener is invoked by {@link ConcurrentLinkedHashMap} on a caller's + * thread and will not block other threads from operating on the map. An + * implementation should be aware that the caller's thread will not expect + * long execution times or failures as a side effect of the listener being + * notified. Execution safety and a fast turn around time can be achieved by + * performing the operation asynchronously, such as by submitting a task to an + * {@link java.util.concurrent.ExecutorService}. + * + * @author ben.manes@gmail.com (Ben Manes) + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +public interface EvictionListener { + + /** + * A call-back notification that the entry was evicted. + * + * @param key the entry's key + * @param value the entry's value + */ + void onEviction(K key, V value); +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/LinkedDeque.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/LinkedDeque.java new file mode 100644 index 0000000000..0354a69f69 --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/LinkedDeque.java @@ -0,0 +1,460 @@ +/* + * Copyright 2011 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.googlecode.concurrentlinkedhashmap; + +import java.util.AbstractCollection; +import java.util.Collection; +import java.util.Deque; +import java.util.Iterator; +import java.util.NoSuchElementException; + +/** + * Linked list implementation of the {@link Deque} interface where the link + * pointers are tightly integrated with the element. Linked deques have no + * capacity restrictions; they grow as necessary to support usage. They are not + * thread-safe; in the absence of external synchronization, they do not support + * concurrent access by multiple threads. Null elements are prohibited. + *

+ * Most LinkedDeque operations run in constant time by assuming that + * the {@link Linked} parameter is associated with the deque instance. Any usage + * that violates this assumption will result in non-deterministic behavior. + *

+ * The iterators returned by this class are not fail-fast: If + * the deque is modified at any time after the iterator is created, the iterator + * will be in an unknown state. Thus, in the face of concurrent modification, + * the iterator risks arbitrary, non-deterministic behavior at an undetermined + * time in the future. + * + * @author ben.manes@gmail.com (Ben Manes) + * @param the type of elements held in this collection + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +final class LinkedDeque> extends AbstractCollection implements Deque { + + // This class provides a doubly-linked list that is optimized for the virtual + // machine. The first and last elements are manipulated instead of a slightly + // more convenient sentinel element to avoid the insertion of null checks with + // NullPointerException throws in the byte code. The links to a removed + // element are cleared to help a generational garbage collector if the + // discarded elements inhabit more than one generation. + + /** + * Pointer to first node. + * Invariant: (first == null && last == null) || + * (first.prev == null) + */ + E first; + + /** + * Pointer to last node. + * Invariant: (first == null && last == null) || + * (last.next == null) + */ + E last; + + /** + * Links the element to the front of the deque so that it becomes the first + * element. + * + * @param e the unlinked element + */ + void linkFirst(final E e) { + final E f = first; + first = e; + + if (f == null) { + last = e; + } else { + f.setPrevious(e); + e.setNext(f); + } + } + + /** + * Links the element to the back of the deque so that it becomes the last + * element. + * + * @param e the unlinked element + */ + void linkLast(final E e) { + final E l = last; + last = e; + + if (l == null) { + first = e; + } else { + l.setNext(e); + e.setPrevious(l); + } + } + + /** Unlinks the non-null first element. */ + E unlinkFirst() { + final E f = first; + final E next = f.getNext(); + f.setNext(null); + + first = next; + if (next == null) { + last = null; + } else { + next.setPrevious(null); + } + return f; + } + + /** Unlinks the non-null last element. */ + E unlinkLast() { + final E l = last; + final E prev = l.getPrevious(); + l.setPrevious(null); + last = prev; + if (prev == null) { + first = null; + } else { + prev.setNext(null); + } + return l; + } + + /** Unlinks the non-null element. */ + void unlink(E e) { + final E prev = e.getPrevious(); + final E next = e.getNext(); + + if (prev == null) { + first = next; + } else { + prev.setNext(next); + e.setPrevious(null); + } + + if (next == null) { + last = prev; + } else { + next.setPrevious(prev); + e.setNext(null); + } + } + + @Override + public boolean isEmpty() { + return (first == null); + } + + void checkNotEmpty() { + if (isEmpty()) { + throw new NoSuchElementException(); + } + } + + /** + * {@inheritDoc} + *

+ * Beware that, unlike in most collections, this method is NOT a + * constant-time operation. + */ + @Override + public int size() { + int size = 0; + for (E e = first; e != null; e = e.getNext()) { + size++; + } + return size; + } + + @Override + public void clear() { + for (E e = first; e != null;) { + E next = e.getNext(); + e.setPrevious(null); + e.setNext(null); + e = next; + } + first = last = null; + } + + @Override + public boolean contains(Object o) { + return (o instanceof Linked) && contains((Linked) o); + } + + // A fast-path containment check + boolean contains(Linked e) { + return (e.getPrevious() != null) + || (e.getNext() != null) + || (e == first); + } + + /** + * Moves the element to the front of the deque so that it becomes the first + * element. + * + * @param e the linked element + */ + public void moveToFront(E e) { + if (e != first) { + unlink(e); + linkFirst(e); + } + } + + /** + * Moves the element to the back of the deque so that it becomes the last + * element. + * + * @param e the linked element + */ + public void moveToBack(E e) { + if (e != last) { + unlink(e); + linkLast(e); + } + } + + @Override + public E peek() { + return peekFirst(); + } + + @Override + public E peekFirst() { + return first; + } + + @Override + public E peekLast() { + return last; + } + + @Override + public E getFirst() { + checkNotEmpty(); + return peekFirst(); + } + + @Override + public E getLast() { + checkNotEmpty(); + return peekLast(); + } + + @Override + public E element() { + return getFirst(); + } + + @Override + public boolean offer(E e) { + return offerLast(e); + } + + @Override + public boolean offerFirst(E e) { + if (contains(e)) { + return false; + } + linkFirst(e); + return true; + } + + @Override + public boolean offerLast(E e) { + if (contains(e)) { + return false; + } + linkLast(e); + return true; + } + + @Override + public boolean add(E e) { + return offerLast(e); + } + + + @Override + public void addFirst(E e) { + if (!offerFirst(e)) { + throw new IllegalArgumentException(); + } + } + + @Override + public void addLast(E e) { + if (!offerLast(e)) { + throw new IllegalArgumentException(); + } + } + + @Override + public E poll() { + return pollFirst(); + } + + @Override + public E pollFirst() { + return isEmpty() ? null : unlinkFirst(); + } + + @Override + public E pollLast() { + return isEmpty() ? null : unlinkLast(); + } + + @Override + public E remove() { + return removeFirst(); + } + + @Override + @SuppressWarnings("unchecked") + public boolean remove(Object o) { + return (o instanceof Linked) && remove((E) o); + } + + // A fast-path removal + boolean remove(E e) { + if (contains(e)) { + unlink(e); + return true; + } + return false; + } + + @Override + public E removeFirst() { + checkNotEmpty(); + return pollFirst(); + } + + @Override + public boolean removeFirstOccurrence(Object o) { + return remove(o); + } + + @Override + public E removeLast() { + checkNotEmpty(); + return pollLast(); + } + + @Override + public boolean removeLastOccurrence(Object o) { + return remove(o); + } + + @Override + public boolean removeAll(Collection c) { + boolean modified = false; + for (Object o : c) { + modified |= remove(o); + } + return modified; + } + + @Override + public void push(E e) { + addFirst(e); + } + + @Override + public E pop() { + return removeFirst(); + } + + @Override + public Iterator iterator() { + return new AbstractLinkedIterator(first) { + @Override E computeNext() { + return cursor.getNext(); + } + }; + } + + @Override + public Iterator descendingIterator() { + return new AbstractLinkedIterator(last) { + @Override E computeNext() { + return cursor.getPrevious(); + } + }; + } + + abstract class AbstractLinkedIterator implements Iterator { + E cursor; + + /** + * Creates an iterator that can can traverse the deque. + * + * @param start the initial element to begin traversal from + */ + AbstractLinkedIterator(E start) { + cursor = start; + } + + @Override + public boolean hasNext() { + return (cursor != null); + } + + @Override + public E next() { + if (!hasNext()) { + throw new NoSuchElementException(); + } + E e = cursor; + cursor = computeNext(); + return e; + } + + @Override + public void remove() { + throw new UnsupportedOperationException(); + } + + /** + * Retrieves the next element to traverse to or null if there are + * no more elements. + */ + abstract E computeNext(); + } +} + +/** + * An element that is linked on the {@link Deque}. + */ +interface Linked> { + + /** + * Retrieves the previous element or null if either the element is + * unlinked or the first element on the deque. + */ + T getPrevious(); + + /** Sets the previous element or null if there is no link. */ + void setPrevious(T prev); + + /** + * Retrieves the next element or null if either the element is + * unlinked or the last element on the deque. + */ + T getNext(); + + /** Sets the next element or null if there is no link. */ + void setNext(T next); +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weigher.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weigher.java new file mode 100644 index 0000000000..2fef7f0e7b --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weigher.java @@ -0,0 +1,36 @@ +/* + * Copyright 2010 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.googlecode.concurrentlinkedhashmap; + +/** + * A class that can determine the weight of a value. The total weight threshold + * is used to determine when an eviction is required. + * + * @author ben.manes@gmail.com (Ben Manes) + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +public interface Weigher { + + /** + * Measures an object's weight to determine how many units of capacity that + * the value consumes. A value must consume a minimum of one unit. + * + * @param value the object to weigh + * @return the object's weight + */ + int weightOf(V value); +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weighers.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weighers.java new file mode 100644 index 0000000000..c3c11a1527 --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/Weighers.java @@ -0,0 +1,282 @@ +/* + * Copyright 2010 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.googlecode.concurrentlinkedhashmap; + +import static com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap.checkNotNull; + +import java.io.Serializable; +import java.util.Collection; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.Set; + +/** + * A common set of {@link Weigher} and {@link EntryWeigher} implementations. + * + * @author ben.manes@gmail.com (Ben Manes) + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +public final class Weighers { + + private Weighers() { + throw new AssertionError(); + } + + /** + * A entry weigher backed by the specified weigher. The weight of the value + * determines the weight of the entry. + * + * @param weigher the weigher to be "wrapped" in a entry weigher. + * @return A entry weigher view of the specified weigher. + */ + public static EntryWeigher asEntryWeigher( + final Weigher weigher) { + return (weigher == singleton()) + ? Weighers.entrySingleton() + : new EntryWeigherView(weigher); + } + + /** + * A weigher where an entry has a weight of 1. A map bounded with + * this weigher will evict when the number of key-value pairs exceeds the + * capacity. + * + * @return A weigher where a value takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static EntryWeigher entrySingleton() { + return (EntryWeigher) SingletonEntryWeigher.INSTANCE; + } + + /** + * A weigher where a value has a weight of 1. A map bounded with + * this weigher will evict when the number of key-value pairs exceeds the + * capacity. + * + * @return A weigher where a value takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static Weigher singleton() { + return (Weigher) SingletonWeigher.INSTANCE; + } + + /** + * A weigher where the value is a byte array and its weight is the number of + * bytes. A map bounded with this weigher will evict when the number of bytes + * exceeds the capacity rather than the number of key-value pairs in the map. + * This allows for restricting the capacity based on the memory-consumption + * and is primarily for usage by dedicated caching servers that hold the + * serialized data. + *

+ * A value with a weight of 0 will be rejected by the map. If a value + * with this weight can occur then the caller should eagerly evaluate the + * value and treat it as a removal operation. Alternatively, a custom weigher + * may be specified on the map to assign an empty value a positive weight. + * + * @return A weigher where each byte takes one unit of capacity. + */ + public static Weigher byteArray() { + return ByteArrayWeigher.INSTANCE; + } + + /** + * A weigher where the value is a {@link Iterable} and its weight is the + * number of elements. This weigher only should be used when the alternative + * {@link #collection()} weigher cannot be, as evaluation takes O(n) time. A + * map bounded with this weigher will evict when the total number of elements + * exceeds the capacity rather than the number of key-value pairs in the map. + *

+ * A value with a weight of 0 will be rejected by the map. If a value + * with this weight can occur then the caller should eagerly evaluate the + * value and treat it as a removal operation. Alternatively, a custom weigher + * may be specified on the map to assign an empty value a positive weight. + * + * @return A weigher where each element takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static Weigher> iterable() { + return (Weigher>) (Weigher) IterableWeigher.INSTANCE; + } + + /** + * A weigher where the value is a {@link Collection} and its weight is the + * number of elements. A map bounded with this weigher will evict when the + * total number of elements exceeds the capacity rather than the number of + * key-value pairs in the map. + *

+ * A value with a weight of 0 will be rejected by the map. If a value + * with this weight can occur then the caller should eagerly evaluate the + * value and treat it as a removal operation. Alternatively, a custom weigher + * may be specified on the map to assign an empty value a positive weight. + * + * @return A weigher where each element takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static Weigher> collection() { + return (Weigher>) (Weigher) CollectionWeigher.INSTANCE; + } + + /** + * A weigher where the value is a {@link List} and its weight is the number + * of elements. A map bounded with this weigher will evict when the total + * number of elements exceeds the capacity rather than the number of + * key-value pairs in the map. + *

+ * A value with a weight of 0 will be rejected by the map. If a value + * with this weight can occur then the caller should eagerly evaluate the + * value and treat it as a removal operation. Alternatively, a custom weigher + * may be specified on the map to assign an empty value a positive weight. + * + * @return A weigher where each element takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static Weigher> list() { + return (Weigher>) (Weigher) ListWeigher.INSTANCE; + } + + /** + * A weigher where the value is a {@link Set} and its weight is the number + * of elements. A map bounded with this weigher will evict when the total + * number of elements exceeds the capacity rather than the number of + * key-value pairs in the map. + *

+ * A value with a weight of 0 will be rejected by the map. If a value + * with this weight can occur then the caller should eagerly evaluate the + * value and treat it as a removal operation. Alternatively, a custom weigher + * may be specified on the map to assign an empty value a positive weight. + * + * @return A weigher where each element takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static Weigher> set() { + return (Weigher>) (Weigher) SetWeigher.INSTANCE; + } + + /** + * A weigher where the value is a {@link Map} and its weight is the number of + * entries. A map bounded with this weigher will evict when the total number of + * entries across all values exceeds the capacity rather than the number of + * key-value pairs in the map. + *

+ * A value with a weight of 0 will be rejected by the map. If a value + * with this weight can occur then the caller should eagerly evaluate the + * value and treat it as a removal operation. Alternatively, a custom weigher + * may be specified on the map to assign an empty value a positive weight. + * + * @return A weigher where each entry takes one unit of capacity. + */ + @SuppressWarnings({"cast", "unchecked"}) + public static Weigher> map() { + return (Weigher>) (Weigher) MapWeigher.INSTANCE; + } + + static final class EntryWeigherView implements EntryWeigher, Serializable { + static final long serialVersionUID = 1; + final Weigher weigher; + + EntryWeigherView(Weigher weigher) { + checkNotNull(weigher); + this.weigher = weigher; + } + + @Override + public int weightOf(K key, V value) { + return weigher.weightOf(value); + } + } + + enum SingletonEntryWeigher implements EntryWeigher { + INSTANCE; + + @Override + public int weightOf(Object key, Object value) { + return 1; + } + } + + enum SingletonWeigher implements Weigher { + INSTANCE; + + @Override + public int weightOf(Object value) { + return 1; + } + } + + enum ByteArrayWeigher implements Weigher { + INSTANCE; + + @Override + public int weightOf(byte[] value) { + return value.length; + } + } + + enum IterableWeigher implements Weigher> { + INSTANCE; + + @Override + public int weightOf(Iterable values) { + if (values instanceof Collection) { + return ((Collection) values).size(); + } + int size = 0; + for (Iterator i = values.iterator(); i.hasNext();) { + i.next(); + size++; + } + return size; + } + } + + enum CollectionWeigher implements Weigher> { + INSTANCE; + + @Override + public int weightOf(Collection values) { + return values.size(); + } + } + + enum ListWeigher implements Weigher> { + INSTANCE; + + @Override + public int weightOf(List values) { + return values.size(); + } + } + + enum SetWeigher implements Weigher> { + INSTANCE; + + @Override + public int weightOf(Set values) { + return values.size(); + } + } + + enum MapWeigher implements Weigher> { + INSTANCE; + + @Override + public int weightOf(Map values) { + return values.size(); + } + } +} diff --git a/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/package-info.java b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/package-info.java new file mode 100644 index 0000000000..57bab113b4 --- /dev/null +++ b/OsmAnd-java/src/com/googlecode/concurrentlinkedhashmap/package-info.java @@ -0,0 +1,41 @@ +/* + * Copyright 2011 Google Inc. All Rights Reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/** + * This package contains an implementation of a bounded + * {@link java.util.concurrent.ConcurrentMap} data structure. + *

+ * {@link com.googlecode.concurrentlinkedhashmap.Weigher} is a simple interface + * for determining how many units of capacity an entry consumes. Depending on + * which concrete Weigher class is used, an entry may consume a different amount + * of space within the cache. The + * {@link com.googlecode.concurrentlinkedhashmap.Weighers} class provides + * utility methods for obtaining the most common kinds of implementations. + *

+ * {@link com.googlecode.concurrentlinkedhashmap.EvictionListener} provides the + * ability to be notified when an entry is evicted from the map. An eviction + * occurs when the entry was automatically removed due to the map exceeding a + * capacity threshold. It is not called when an entry was explicitly removed. + *

+ * The {@link com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap} + * class supplies an efficient, scalable, thread-safe, bounded map. As with the + * Java Collections Framework the "Concurrent" prefix is used to + * indicate that the map is not governed by a single exclusion lock. + * + * @see + * http://code.google.com/p/concurrentlinkedhashmap/ + */ +package com.googlecode.concurrentlinkedhashmap; diff --git a/OsmAnd/src/net/osmand/plus/audionotes/AudioVideoNotesPlugin.java b/OsmAnd/src/net/osmand/plus/audionotes/AudioVideoNotesPlugin.java index 46943c3427..124196f5c4 100644 --- a/OsmAnd/src/net/osmand/plus/audionotes/AudioVideoNotesPlugin.java +++ b/OsmAnd/src/net/osmand/plus/audionotes/AudioVideoNotesPlugin.java @@ -35,6 +35,8 @@ import android.widget.ArrayAdapter; import android.widget.ImageView; import android.widget.Toast; +import com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap; + import net.osmand.AndroidUtils; import net.osmand.IProgress; import net.osmand.IndexConstants; @@ -75,10 +77,8 @@ import java.lang.reflect.Constructor; import java.lang.reflect.Method; import java.util.Arrays; import java.util.Collection; -import java.util.Collections; import java.util.Comparator; import java.util.Iterator; -import java.util.LinkedHashMap; import java.util.List; import java.util.Map; @@ -130,18 +130,22 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { public final OsmandPreference SHOW_RECORDINGS; private DataTileManager recordings = new DataTileManager(14); - private Map recordingByFileName = Collections.synchronizedMap(new LinkedHashMap()); + private Map recordingByFileName = + new ConcurrentLinkedHashMap.Builder() + .maximumWeightedCapacity(1000) + .build(); private AudioNotesLayer audioNotesLayer; private MapActivity activity; private MediaRecorder mediaRec; private File lastTakingPhoto; - private final static char SPLIT_DESC = ' '; + private final static char SPLIT_DESC = ' '; + public static class Recording { public Recording(File f) { this.file = f; } - + private File file; private double lat; @@ -178,7 +182,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { public File getFile() { return file; } - + public boolean setName(String name) { File directory = file.getParentFile(); @@ -194,24 +198,24 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { public String getFileName() { return file.getName(); } - + public String getDescriptionName(String fileName) { int hashInd = fileName.lastIndexOf(SPLIT_DESC); //backward compatibility - if( fileName.indexOf('.') - fileName.indexOf('_') > 12 && + if (fileName.indexOf('.') - fileName.indexOf('_') > 12 && hashInd < fileName.indexOf('_')) { hashInd = fileName.indexOf('_'); } - if(hashInd == -1) { + if (hashInd == -1) { return null; } else { return fileName.substring(0, hashInd); } } - + public String getOtherName(String fileName) { String descriptionName = getDescriptionName(fileName); - if(descriptionName != null) { + if (descriptionName != null) { return fileName.substring(descriptionName.length() + 1); // SPLIT_DESC } else { return fileName; @@ -233,8 +237,8 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { return ""; } - public String getSearchHistoryType(){ - if (isPhoto()){ + public String getSearchHistoryType() { + if (isPhoto()) { return PointDescription.POINT_TYPE_PHOTO_NOTE; } else if (isVideo()) { return PointDescription.POINT_TYPE_VIDEO_NOTE; @@ -350,7 +354,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { return ctx.getString(R.string.recording_description, "", getDuration(ctx), time) .trim(); } - + public String getSmallDescription(Context ctx) { String time = AndroidUtils.formatDateTime(ctx, file.lastModified()); if (isPhoto()) { @@ -358,7 +362,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { } updateInternalDescription(); return time + " " + getDuration(ctx); - + } private String getDuration(Context ctx) { @@ -445,7 +449,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { } audioNotesLayer = new AudioNotesLayer(activity, this); activity.getMapView().addLayer(audioNotesLayer, 3.5f); - if(recordControl == null) { + if (recordControl == null) { registerWidget(activity); } } @@ -535,7 +539,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { } else if (audioNotesLayer != null) { mapView.removeLayer(audioNotesLayer); } - if(recordControl == null) { + if (recordControl == null) { registerWidget(activity); } } else { @@ -544,7 +548,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { audioNotesLayer = null; } MapInfoLayer mapInfoLayer = activity.getMapLayers().getMapInfoLayer(); - if(recordControl != null && mapInfoLayer != null) { + if (recordControl != null && mapInfoLayer != null) { mapInfoLayer.removeSideWidget(recordControl); recordControl = null; mapInfoLayer.recreateControls(); @@ -1291,7 +1295,7 @@ public class AudioVideoNotesPlugin extends OsmandPlugin { } } } - + @Override public int getLogoResourceId() { return R.drawable.ic_action_micro_dark;