Pair.java

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 * Copyright (c) 2011, Daniel Murphy
 * All rights reserved.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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package org.jbox2d.collision.broadphase;

import java.util.Comparator;

// updated to rev 100
/**
 * Java note: at the "creation" of each node, a random key is given to
 * that node, and that's what we sort from.
 */
public class Pair {
	public DynamicTreeNode proxyA;
	public DynamicTreeNode proxyB;
	public int stableIdx;
	
	public int compareTo(Pair pair2) {
		if (this.proxyA.key < pair2.proxyA.key) {
			return -1;
		}
		
		if (this.proxyA.key == pair2.proxyA.key) {
			
			if (proxyB.key < pair2.proxyB.key) {
				return -1;
			}
			else {
				if (proxyB.key == pair2.proxyB.key) {
					return 0;
				}
				else {
					return 1;
				}
			}
		}
		
		return 1;
	}

	/**
	 * Note: Must set pair.stableIdx before using to ensure stability.
	 */
	public static class StableComparator implements Comparator<Pair> {
    @Override
    public int compare(Pair pair1, Pair pair2) {
      int stdRtn = pair1.compareTo(pair2);
      if (stdRtn == 0) {
        if (pair1.stableIdx < pair2.stableIdx) {
          return -1;
        } else if (pair1.stableIdx > pair2.stableIdx) {
          return 1;
        } else {
          return 0;
        }
      } else {
        return stdRtn;
      }
    }
  }

	 public static class PairComparator implements Comparator<Pair> {
	    @Override
	    public int compare(Pair pair1, Pair pair2) {
	      return pair1.compareTo(pair2);
	    }
	  }
}