ackedqueue.java

一个类似于openJMS分布在ObjectWeb之下的JMS消息中间件。

/*
 * JORAM: Java(TM) Open Reliable Asynchronous Messaging
 * Copyright (C) 2004 - ScalAgent Distributed Technologies
 * Copyright (C) 2004 - France Telecom R&D
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA.
 *
 * Initial developer(s): ScalAgent Distributed Technologies
 */
package org.objectweb.joram.mom.proxies;

import org.objectweb.util.monolog.api.BasicLevel;
import org.objectweb.joram.mom.MomTracing;

import java.util.*;

public class AckedQueue implements java.io.Serializable {

  private Vector list;

  private int current;

  public AckedQueue() {
    list = new Vector();
    current = 0;
  }

  public void push(ProxyMessage msg) {
    if (MomTracing.dbgProxy.isLoggable(BasicLevel.DEBUG))
      MomTracing.dbgProxy.log(
        BasicLevel.DEBUG, "AckedQueue.push(" + msg + ')');
    synchronized (list) {
      list.addElement(msg);
      list.notify();
    }
  }

  public ProxyMessage get() throws InterruptedException {
    if (MomTracing.dbgProxy.isLoggable(BasicLevel.DEBUG))
      MomTracing.dbgProxy.log(
        BasicLevel.DEBUG, "AckedQueue.get()");
    synchronized (list) { 
      while ((list.size() - current) == 0) {
	list.wait();
      }      
      ProxyMessage msg = 
        (ProxyMessage)list.elementAt(current);
      current++;
      return msg;
    }
  }

  public void ack(long ackId) {
    if (MomTracing.dbgProxy.isLoggable(BasicLevel.DEBUG))
      MomTracing.dbgProxy.log(
        BasicLevel.DEBUG, "AckedQueue.ack(" + ackId + ')');
    synchronized (list) {
      while (list.size() > 0) {
        ProxyMessage m = 
	  (ProxyMessage)list.elementAt(0);
	if (ackId < m.getId()) {          
	  return;
	} else {
	  // acked
          if (MomTracing.dbgProxy.isLoggable(BasicLevel.DEBUG))
            MomTracing.dbgProxy.log(
              BasicLevel.DEBUG, "AckedQueue acked " + m.getId());
	  list.removeElementAt(0);
          if (current > 0) {
            current--;
          }
	}
      }
    }
  }

  public void reset() {
    if (MomTracing.dbgProxy.isLoggable(BasicLevel.DEBUG))
      MomTracing.dbgProxy.log(
        BasicLevel.DEBUG, "AckedQueue.reset()");
    current = 0;
  }
}