unorderedpair.java

Standord Classifier实现了一个基于Java的最大熵分类器。用于模式识别

package edu.stanford.nlp.util;

import java.util.*;

/**
 *  Unordered Pair
 *
 *  Class for holding an unordered pair of objects
 *
 *  @author Dan Klein
 *  @version 2/7/01
 */
public class UnorderedPair extends Pair {

  public String toString() {
    return "{"+first+","+second+"}";
  }
  
  public boolean equals(Object o) {
    if (o instanceof UnorderedPair) {
      UnorderedPair p = (UnorderedPair)o;
      return (((first==null ? p.first==null : first.equals(p.first)) &&
	       (second==null ? p.second==null : second.equals(p.second))) ||
	      ((first==null ? p.second==null : first.equals(p.second)) &&
	       (second==null ? p.first==null : second.equals(p.first))));
    }
    return false;
  }
  
  public int hashCode() {
    return first.hashCode() ^ second.hashCode();
  }

  public UnorderedPair() {first = null; second = null;}

  public UnorderedPair(Object first, Object second) {
    this.first = first;
    this.second = second;
  }  

}