001    /**
002     *   GRANITE DATA SERVICES
003     *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004     *
005     *   This file is part of the Granite Data Services Platform.
006     *
007     *   Granite Data Services is free software; you can redistribute it and/or
008     *   modify it under the terms of the GNU Lesser General Public
009     *   License as published by the Free Software Foundation; either
010     *   version 2.1 of the License, or (at your option) any later version.
011     *
012     *   Granite Data Services is distributed in the hope that it will be useful,
013     *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014     *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015     *   General Public License for more details.
016     *
017     *   You should have received a copy of the GNU Lesser General Public
018     *   License along with this library; if not, write to the Free Software
019     *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020     *   USA, or see <http://www.gnu.org/licenses/>.
021     */
022    package org.granite.gravity;
023    
024    import java.util.concurrent.atomic.AtomicBoolean;
025    
026    /**
027     * @author Franck WOLFF
028     */
029    public abstract class AsyncChannelRunner implements Runnable {
030    
031            protected final Channel channel;
032            private final AtomicBoolean queued = new AtomicBoolean(false);
033            
034            public AsyncChannelRunner(Channel channel) {
035                    this.channel = channel;
036            }
037            
038            public final boolean queue(Gravity gravity) {
039                    if (queued.getAndSet(true))
040                            return false;
041                    gravity.execute(this);
042                    return true;
043            }
044            
045            public final void reset() {
046                    queued.set(false);
047            }
048            
049            protected abstract void doRun();
050            
051            public final void run() {
052                    try {
053                            doRun();
054                    }
055                    finally {
056                            queued.set(false);
057                    }
058            }
059    
060            @Override
061            public boolean equals(Object obj) {
062                    return getClass().isInstance(obj) && channel.equals(((AsyncChannelRunner)obj).channel);
063            }
064    
065            @Override
066            public int hashCode() {
067                    return channel.hashCode();
068            }
069    }