45b8c23ee8
git-svn-id: https://osmand.googlecode.com/svn/trunk@592 e29c36b1-1cfa-d876-8d93-3434fc2bb7b8
103 lines
3.3 KiB
Java
103 lines
3.3 KiB
Java
//ABL.java
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//
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//This library is free software; you can redistribute it and/or
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//modify it under the terms of the GNU Lesser General Public
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//License as published by the Free Software Foundation; either
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//version 2.1 of the License, or (at your option) any later version.
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//
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//This library is distributed in the hope that it will be useful,
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//but WITHOUT ANY WARRANTY; without even the implied warranty of
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//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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//Lesser General Public License for more details.
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package rtree;
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//package rtree;
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/**Active Branch List
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This class will consist of the Elements and their MINDIST from the point of query.
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When the array of this object is returned by the 'nearestSearch' method,
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kindly type cast 'Elemen't to 'LeafElement' when necessary.
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This library should be considered as an open source library. Formal GNU licensing I will include later.
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*/
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public class ABL implements Cloneable
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{
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/**
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Please type cast it to LeafElement when used as a returned value of
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the 'nearestSearch' method.
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*/
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public Element element;
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/**By Definition - The distance of a point P in Euclidean space (E(n))
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from a rectangle R in the same space, denoted by MINDIST(P,R).<br>
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In English - This is the minimum distance between the query point P
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and the MBR of the object.
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<b>Note:-</b> The distance(minDist) is the square of the actual distance.
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To get the actual distance, call <b>Math.sqrt(minDist)</b> (cast minDist to
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Double).
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*/
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public long minDist;//MINDIST(P,this)
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public ABL(Element element,long minDist)
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{
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this.element = element;
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this.minDist = minDist;
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}
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//Uses Two-Way-Merge-Sort (Recursive)
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//Sorts an ABL array based on minDist. Make sure there are no null values.
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public void mergeSort(ABL[] arrABL)
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{
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twoWayMerge(arrABL,0,arrABL.length-1);
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}
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private void twoWayMerge(ABL[] arrABL,int start,int finish)
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{
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try{
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int size = finish - start+1;
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if(size <= 2){
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if(size < 2)
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return;
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ABL temp;
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if(arrABL[start].minDist > arrABL[finish].minDist){
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temp = arrABL[start];
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arrABL[start] = arrABL[finish];
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arrABL[finish] = temp;
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}
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return;
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}
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Double middle = new Double(start+finish);
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middle = new Double(Math.ceil(middle.doubleValue()/2));
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twoWayMerge(arrABL,start,middle.intValue());
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twoWayMerge(arrABL,middle.intValue(),finish);
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simpleMerge(arrABL,start,middle.intValue(),finish);
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}
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catch(Exception e){
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System.out.println("rtree.ABL.twoWayMerge: most probably a null value in array");
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}
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}
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//simple merge
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private void simpleMerge(ABL[] arrABL,int first,int second,int third)
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throws Exception
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{
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int i = first;
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int j = second;
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int l = 0;
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ABL[] temp = new ABL[third-first+1];
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while((i < second) && (j <= third)){//loop till one lasts
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if(arrABL[i].minDist <= arrABL[j].minDist)
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temp[l++] = arrABL[i++];
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else
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temp[l++] = arrABL[j++];
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}
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//copy the rest
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if(i >= second)//give second section
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while(j <= third)
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temp[l++] = arrABL[j++];
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else
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while(i < second)//give first section
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temp[l++] = arrABL[i++];
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System.arraycopy(temp,0,arrABL,first,temp.length);
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}
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public Object clone()
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{
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return new ABL(element,minDist);
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}
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}//class ABL
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