/*
* 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.ObjectOutputStream;
import java.io.StreamCorruptedException;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferInputStream;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
/**
* A decoder which deserializes the received {@link ChannelBuffer}s into Java
* objects.
* <p>
* Please note that the serialized form this decoder expects is not
* compatible with the standard {@link ObjectOutputStream}. Please use
* {@link ObjectEncoder} or {@link ObjectEncoderOutputStream} to ensure the
* interoperability with this decoder.
*
* @author The Netty Project (netty-dev@lists.jboss.org)
* @author Trustin Lee (tlee@redhat.com)
*
* @version $Rev: 1072 $, $Date: 2009-03-16 16:52:19 +0900 (Mon, 16 Mar 2009) $
*
* @apiviz.landmark
*/
public class ObjectDecoder extends FrameDecoder {
private final int maxObjectSize;
private final ClassLoader classLoader;
/**
* Creates a new decoder whose maximum object size is {@code 1048576}
* bytes. If the size of the received object is greater than
* {@code 1048576} bytes, a {@link StreamCorruptedException} will be
* raised.
*/
public ObjectDecoder() {
this(1048576);
}
/**
* Creates a new decoder with the specified maximum object size.
*
* @param maxObjectSize the maximum byte length of the serialized object.
* if the length of the received object is greater
* than this value, {@link StreamCorruptedException}
* will be raised.
*/
public ObjectDecoder(int maxObjectSize) {
this(maxObjectSize, null);
}
/**
* Creates a new decoder with the specified maximum object size.
*
* @param maxObjectSize the maximum byte length of the serialized object.
* if the length of the received object is greater
* than this value, {@link StreamCorruptedException}
* will be raised.
* @param classLoader the {@link ClassLoader} which will load the class
* of the serialized object
*/
public ObjectDecoder(int maxObjectSize, ClassLoader classLoader) {
if (maxObjectSize <= 0) {
throw new IllegalArgumentException("maxObjectSize: " + maxObjectSize);
}
this.maxObjectSize = maxObjectSize;
this.classLoader = classLoader;
}
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {
if (buffer.readableBytes() < 4) {
return null;
}
int dataLen = buffer.getInt(buffer.readerIndex());
if (dataLen <= 0) {
throw new StreamCorruptedException("invalid data length: " + dataLen);
}
if (dataLen > maxObjectSize) {
throw new StreamCorruptedException(
"data length too big: " + dataLen + " (max: " + maxObjectSize + ')');
}
if (buffer.readableBytes() < dataLen + 4) {
return null;
}
buffer.skipBytes(4);
return new CompactObjectInputStream(
new ChannelBufferInputStream(buffer, dataLen), classLoader).readObject();
}
}