/*
* JBoss, Home of Professional Open Source
*
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* by the @author tags. See the COPYRIGHT.txt in the distribution for a
* full listing of individual contributors.
*
* This 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 (at your option) any later version.
*
* This software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.netty.handler.codec.serialization;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.util.concurrent.atomic.AtomicReference;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferFactory;
import org.jboss.netty.buffer.ChannelBufferOutputStream;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipelineCoverage;
import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
/**
* An encoder which serializes a Java object into a {@link ChannelBuffer}
* (interoperability version).
* <p>
* This encoder is interoperable with the standard Java object streams such as
* {@link ObjectInputStream} and {@link ObjectOutputStream}.
*
* @author The Netty Project (netty-dev@lists.jboss.org)
* @author Trustin Lee (tlee@redhat.com)
*
* @version $Rev:231 $, $Date:2008-06-12 16:44:50 +0900 (목, 12 6월 2008) $
*/
@ChannelPipelineCoverage("one")
public class CompatibleObjectEncoder extends OneToOneEncoder {
private final AtomicReference<ChannelBuffer> buffer =
new AtomicReference<ChannelBuffer>();
private final int resetInterval;
private volatile ObjectOutputStream oout;
private int writtenObjects;
/**
* Creates a new instance with the reset interval of {@code 16}.
*/
public CompatibleObjectEncoder() {
this(16); // Reset at every sixteen writes
}
/**
* Creates a new instance.
*
* @param resetInterval
* the number of objects between {@link ObjectOutputStream#reset()}.
* {@code 0} will disable resetting the stream, but the remote
* peer will be at the risk of getting {@link OutOfMemoryError} in
* the long term.
*/
public CompatibleObjectEncoder(int resetInterval) {
if (resetInterval < 0) {
throw new IllegalArgumentException(
"resetInterval: " + resetInterval);
}
this.resetInterval = resetInterval;
}
/**
* Creates a new {@link ObjectOutputStream} which wraps the specified
* {@link OutputStream}. Override this method to use a subclass of the
* {@link ObjectOutputStream}.
*/
protected ObjectOutputStream newObjectOutputStream(OutputStream out) throws Exception {
return new ObjectOutputStream(out);
}
@Override
protected Object encode(ChannelHandlerContext context, Channel channel, Object msg) throws Exception {
ChannelBuffer buffer = buffer(context);
ObjectOutputStream oout = this.oout;
if (resetInterval != 0) {
// Resetting will prevent OOM on the receiving side.
writtenObjects ++;
if (writtenObjects % resetInterval == 0) {
oout.reset();
// Also discard the byproduct to avoid OOM on the sending side.
buffer.discardReadBytes();
}
}
oout.writeObject(msg);
oout.flush();
ChannelBuffer encoded = buffer.readBytes(buffer.readableBytes());
return encoded;
}
private ChannelBuffer buffer(ChannelHandlerContext ctx) throws Exception {
ChannelBuffer buf = buffer.get();
if (buf == null) {
ChannelBufferFactory factory = ctx.getChannel().getConfig().getBufferFactory();
buf = ChannelBuffers.dynamicBuffer(factory);
if (buffer.compareAndSet(null, buf)) {
boolean success = false;
try {
oout = newObjectOutputStream(new ChannelBufferOutputStream(buf));
success = true;
} finally {
if (!success) {
oout = null;
}
}
} else {
buf = buffer.get();
}
}
return buf;
}
}