pinghandler.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.*;

/**
 * A concrete implementation of AbstractPingHandler that listens for only
 * inbound ping requests.
 */
public class PingHandler extends AbstractPingHandler implements Runnable {
    
    
    // PingListeners
    Vector listeners = new Vector();
    
    public PingHandler(InputPipe pipe) {
        super(pipe); 
    }
    
    /**
     * 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 {
            //ping.println2("got ping msg "+msg);
            buffer = msg.getBytes("ping");
            String message = new String(buffer);
            
            // Parse values out of ping message
            StringTokenizer st = new StringTokenizer(message,":");
            String name = st.nextToken();
            String timestr = (String)st.nextToken();
            long ostamp = new Long(timestr).longValue();
            
            
            PingEvent pr = new PingEvent(this,name,ostamp,timestamp);
            
            // notify listeners
            notifyListeners(pr);
        } catch (Exception e) {
            e.printStackTrace();
            pipe.close();
        }
    }
    /**
     * Notify interested listeners that a PingEvent has occured and send the
     * ping event.
     */
    private void notifyListeners(PingEvent event) {
        for(int i=0;i<listeners.size();i++)
            ((PingListener)listeners.elementAt(i)).pingEvent(event);
    }
    
    public void addPingListener(PingListener ppml) {
        listeners.addElement(ppml);
    }
    
    public void removePingListener(PingListener ppml) {
        listeners.removeElement(ppml);
    }
    
}