idcomparer.java

p2p仿真器。开发者可以工作在覆盖层中进行创造和测试逻辑算法或者创建和测试新的服务。PlanetSim还可以将仿真代码平稳转换为在Internet上的实验代码

package planet.symphony;

import java.util.Comparator;

import planet.commonapi.Id;
import planet.commonapi.NodeHandle;
/**
 * This is class is used to compare two ids. For that purpose, it implements interface Comparer.
 * This includes a method called <b>compare</b> which returns a negative integer, zero, or a 
 * positive integer as the first argument is less than, equal to, or greater than the second.
 * 
 * @author <a href=mailto:[e-mail]>Marc Sanchez</a>
 * @author <a href=mailto:[e-mail]>Jordi Pujol</a> 
 */

public class IdComparer implements Comparer, Comparator, java.io.Serializable {
    
	private Id root;
    private int result1 = 0;
    private int result2 = 0;
    private Id id1 = null;
    private Id id2 = null;
    
    
	public IdComparer(NodeHandle root) {
		this.root = root.getId();
	}
	
	public int compare(Object o1, Object o2) {
        id1 = ((NodeHandle)o1).getId();
        id2 = ((NodeHandle)o2).getId();
        result1 = id1.compareTo(root);
        result2 = id2.compareTo(root);
        if (result1 > 0 && result2 > 0)
            return id1.compareTo(id2);
        else if (result1 < 0 && result2 < 0)
            return id1.compareTo(id2);
        else 
        {
            if (result1 >= 0 && result2 < 0) return -1;
            else if (result1 < 0 && result2 >= 0) return 1;
            else if (result1 == 0) return (result2==0)?0:-1;
            else return (result1==0)?0:1;  //==> result2 == 0
        }
	}
    
	public boolean equals(Object o)
	{
	    return (o instanceof IdComparer);
	}
}