package org.jacorb.notification.queue;
/*
* JacORB - a free Java ORB
*
* Copyright (C) 1999-2004 Gerald Brose
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import org.jacorb.notification.interfaces.Message;
/**
* Note that most of the methods are not thread-safe. this causes no problem as the methods are not
* intended to be directly called by clients. instead the superclass implements the interface
* EventQueue and invokes the methods thereby synchronizing access.
*
* @author Alphonse Bendt
* @version $Id: BoundedFifoEventQueue.java,v 1.7 2006/02/25 15:28:40 alphonse.bendt Exp $
*/
public class BoundedFifoEventQueue extends AbstractBoundedEventQueue
{
private final LinkedList linkedList_;
public BoundedFifoEventQueue(int maxSize, EventQueueOverflowStrategy overflowStrategy)
{
this(maxSize, overflowStrategy, new Object());
}
public BoundedFifoEventQueue(int maxSize, EventQueueOverflowStrategy overflowStrategy,
Object lock)
{
super(maxSize, overflowStrategy, lock);
linkedList_ = new LinkedList();
}
public String getOrderPolicyName()
{
return "FifoOrder";
}
public boolean isEmpty()
{
return linkedList_.isEmpty();
}
public int getSize()
{
return linkedList_.size();
}
protected Message getEarliestTimeout()
{
final List _sorted = (List) linkedList_.clone();
Collections.sort(_sorted, QueueUtil.ASCENDING_TIMEOUT_COMPARATOR);
final Message _event = (Message) _sorted.get(0);
linkedList_.remove(_event);
return _event;
}
protected Message getLeastPriority()
{
final List _sorted = (List) linkedList_.clone();
Collections.sort(_sorted, QueueUtil.ASCENDING_PRIORITY_COMPARATOR);
final Message _event = (Message) _sorted.get(0);
linkedList_.remove(_event);
return _event;
}
protected Message getNextElement()
{
return getOldestElement();
}
protected Message getOldestElement()
{
return (Message) linkedList_.removeFirst();
}
protected Message getYoungestElement()
{
return (Message) linkedList_.removeLast();
}
protected Message[] getAllElements()
{
try
{
return (Message[]) linkedList_.toArray(QueueUtil.MESSAGE_ARRAY_TEMPLATE);
}
finally
{
linkedList_.clear();
}
}
protected void addElement(Message e)
{
linkedList_.add(e);
}
protected Message[] getElements(int max)
{
final int _retSize = (max > linkedList_.size()) ? linkedList_.size() : max;
final Message[] _result = new Message[_retSize];
for (int x = 0; x < _retSize; ++x)
{
_result[x] = (Message) linkedList_.removeFirst();
}
return _result;
}
}