Source code: ReplyHandler.java

package nl.west.aaa;

import java.util.*;
import java.io.*;

public class ReplyHandler
    implements MessageHandler
{

    /**
     * Messages awaiting a reply. All incoming messages
     * are first checked if they are a reply to
     * any of these messages.
     */
    private Hashtable awaitingReply=new Hashtable();

    /**
     * Prepare this message for receiving a reply.
     * This should be done before sending the message
     * because the reply micht come in
     * before it is waited upon.
     */
    public void prepareForReply(Message msg)
    {
        //msg.foundReply=null;
        awaitingReply.put(msg,null);
    }
    
    /**
     * Wait for a reply to the message to come in.
     * This method blocks until a reply is handled.
     */
    public Message waitForReply(Message msg,long timeout)
    {
        synchronized (msg)
        {
            try 
            {
                // only wait if no reply is in yet
                if(awaitingReply.get(msg)==null)
                    msg.wait(timeout);
            }
            catch (InterruptedException e)
            {
            }
            Message reply=(Message)awaitingReply.get(msg);
            // remove it as waiting for a reply
            awaitingReply.remove(msg);
            // return it
            return reply;
        }
    }

    /**
     * If the message is a reply to a registered
     * waiter, the waiter is woken up and
     * true is returned.
     */
    public boolean handleMessage(Message msg,AAAUnit unit)
    {
        // check all waiting messages
        Enumeration e=awaitingReply.keys();
        while(e.hasMoreElements())
        {
            Message orr=(Message)e.nextElement();
            if(msg.isReplyTo(orr))
            {
                synchronized (orr)
                {
                    //orr.foundReply=msg;
                    //awaitingReply.remove(orr);
                    orr.notifyAll();
                    return true;
                }
            }
        }
        return false;
    }

}