ackmcastreceiverwindow.java

JGRoups源码

// $Id: AckMcastReceiverWindow.java,v 1.8 2006/05/16 11:14:28 belaban Exp $

package org.jgroups.stack;


import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jgroups.Address;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import java.net.UnknownHostException;


/**
 * Keeps track of messages received from various senders. Acks each message received and checks whether
 * it was already delivered. If yes, the message is discarded, otherwise it is delivered (passed up).
 * The messages contain sequence numbers of old messages to be deleted, those are removed from the
 * message table.
 * 
 * @author Bela Ban June 17 1999
 */
public class AckMcastReceiverWindow {
    final Hashtable msgs=new Hashtable();  // sender -- Vector (of seqnos)

    protected static final Log log=LogFactory.getLog(AckMcastReceiverWindow.class);



    /**
       Records the sender/seqno pair in the message table
       @param sender The sender of the message
       @param seqno The sequence number associated with the message
       @return boolean If false, message is already present. Otherwise true.
     */
    public boolean add(Object sender, long seqno) {
    Vector seqnos=(Vector)msgs.get(sender);
    Long   val=new Long(seqno);

    if(seqnos == null) {
        seqnos=new Vector();
        seqnos.addElement(val);
        msgs.put(sender, seqnos);
        return true;
    }

    if(seqnos.contains(val))
        return false;

    seqnos.addElement(val);
    return true;
    }




    public void remove(Object sender, Vector seqnos) {
    Vector v=(Vector)msgs.get(sender);
    Long   seqno;

    if(v != null && seqnos != null) {
        for(int i=0; i < seqnos.size(); i++) {
        seqno=(Long)seqnos.elementAt(i);
        v.removeElement(seqno);
        }
    }
    }



    public long size() {
    long ret=0;

    for(Enumeration e=msgs.elements(); e.hasMoreElements();) {
        ret+=((Vector)e.nextElement()).size();
    }

    return ret;
    }


    public void reset() {
    removeAll();
    }

    public void removeAll() {msgs.clear();}


    public void suspect(Object sender) {

        if(log.isInfoEnabled()) log.info("suspect is " + sender);
    msgs.remove(sender);
    }



    public String toString() {
    StringBuffer ret=new StringBuffer();
    Object       sender;

    for(Enumeration e=msgs.keys(); e.hasMoreElements();) {
        sender=e.nextElement();
        ret.append(sender).append(" --> ").append(msgs.get(sender)).append('\n');
    }
    return ret.toString();
    }






    public static void main(String[] args) throws UnknownHostException {
        AckMcastReceiverWindow win=new AckMcastReceiverWindow();
        Address sender1=new IpAddress("janet", 1111);
        Address sender2=new IpAddress("janet", 4444);
        Address sender3=new IpAddress("janet", 6767);
        Address sender4=new IpAddress("janet", 3333);

        win.add(sender1, 1);
        win.add(sender1, 2);

        win.add(sender3, 2);
        win.add(sender2, 2);
        win.add(sender4, 2);
        win.add(sender1, 3);
        win.add(sender1, 2);


        System.out.println(win);

        win.suspect(sender1);
        System.out.println(win);

        win.add(sender1, 1);
        win.add(sender1, 2);
        win.add(sender1, 3);
        win.add(sender1, 4);
        win.add(sender1, 5);
        win.add(sender1, 6);
        win.add(sender1, 7);
        win.add(sender1, 8);

        System.out.println(win);


        Vector seqnos=new Vector();

        seqnos.addElement(new Long(4));
        seqnos.addElement(new Long(6));
        seqnos.addElement(new Long(8));

        win.remove(sender2, seqnos);
        System.out.println(win);

        win.remove(sender1, seqnos);
        System.out.println(win);


    }

}