/*
* Copyright 2004-2006 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.sf.cindy.decoder;
import java.util.Collection;
import java.util.Iterator;
import net.sf.cindy.Buffer;
import net.sf.cindy.Packet;
import net.sf.cindy.PacketDecoder;
import net.sf.cindy.Session;
import edu.emory.mathcs.backport.java.util.concurrent.CopyOnWriteArrayList;
/**
* <code>PacketDecoder</code> chain.
*
* @author <a href="chenrui@gmail.com">Roger Chen</a>
* @version $id$
*/
public class PacketDecoderChain implements PacketDecoder {
private final Collection chain = new CopyOnWriteArrayList();
public PacketDecoderChain addPacketDecoder(PacketDecoder decoder) {
if (decoder != null)
chain.add(decoder);
return this;
}
public PacketDecoderChain removePacketDecoder(PacketDecoder decoder) {
chain.remove(decoder);
return this;
}
public Object decode(Session session, Packet packet) throws Exception {
Buffer content = packet.getContent();
int position = content.position();
int limit = content.limit();
for (Iterator iter = chain.iterator(); iter.hasNext();) {
PacketDecoder decoder = (PacketDecoder) iter.next();
Object obj = decoder.decode(session, packet);
if (obj != null)
return obj;
// not use slice to create new buffer, reduce memory cost
content.limit(limit);
content.position(position);
}
return null;
}
}