pingreplyhandler.java

Java p2p程序设计2002年版

package net.jxta.impl.shell.bin.ping;


import java.io.*;
import net.jxta.exception.*;
import net.jxta.discovery.*;
import net.jxta.endpoint.*;
import net.jxta.pipe.*;
import net.jxta.peergroup.*;
import net.jxta.document.*;
import net.jxta.id.*;
import net.jxta.protocol.*;
import java.util.*;

/**
 * This handler class listens on a supplied pipe for ping reply messages
 * and notifies its listeners when one does.
 */
public class PingReplyHandler extends AbstractPingHandler implements Runnable {
    
    Vector listeners = new Vector();
    
    public PingReplyHandler(InputPipe pipe) {
        super(pipe);
    }
        
    /**
     * Notify listeners of a ping reply event.
     * @param event The PingReplyEvent
     */
    protected void notifyListeners(PingReplyEvent event) {
        for(int i=0;i<listeners.size();i++)
            ((PingReplyListener)listeners.elementAt(i)).pingReply(event);
    }
    
    public void addPingReplyListener(PingReplyListener ppml) {
        listeners.addElement(ppml);
    }
    
    public void removePingReplyListener(PingReplyListener ppml) {
        listeners.removeElement(ppml);
    }    
    
    /**
     * This key method is abstractly declared in AbstractPingHandler which
     * delegates to subclasses here.
     * @param msg The Message object received on the pipe
     * @param timestamp The timestamp the message was received on the pipe
     */
    protected void deliverMessage(Message msg, long timestamp) {
            Enumeration enum = msg.getNames();
            if ((enum == null) || (!enum.hasMoreElements())) {
                // Empty message
                return;
            }
            byte[] buffer = null;
            
            try {
                buffer = msg.getBytes("reply");
                String message = new String(buffer);
                StringTokenizer st = new StringTokenizer(message,":");
                
                // The peer's name
                String peername = st.nextToken();
                
                // Time it took for original ping request to reach peer.
                long time = new Long(st.nextToken()).longValue();
                
                // Time the ping was received on the peer
                long tstamp = new Long(st.nextToken()).longValue();
                
                PingReplyEvent pr = new PingReplyEvent(this,time,tstamp,timestamp,peername);
                notifyListeners(pr);                    
            } catch (Exception e) {
                // No user information
            }                    
    }
    
}