/*
* Copyright 2011 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.handler.codec.serialization;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;
import io.netty.buffer.ChannelBuffer;
import io.netty.buffer.ChannelBufferInputStream;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.frame.LengthFieldBasedFrameDecoder;
/**
* 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.
* @apiviz.landmark
* @apiviz.has io.netty.handler.codec.serialization.ObjectDecoderInputStream - - - compatible with
*/
public class ObjectDecoder extends LengthFieldBasedFrameDecoder {
private final ClassResolver classResolver;
/**
* 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.
*
* @deprecated use {@link #ObjectDecoder(ClassResolver)}
*/
@Deprecated
public ObjectDecoder() {
this(1048576);
}
/**
* 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.
*
* @param classResolver the {@link ClassResolver} to use for this decoder
*/
public ObjectDecoder(ClassResolver classResolver) {
this(1048576, classResolver);
}
/**
* 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.
* @deprecated use {@link #ObjectDecoder(int, ClassResolver)}
*/
@Deprecated
public ObjectDecoder(int maxObjectSize) {
this(maxObjectSize, ClassResolvers.weakCachingResolver(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 classResolver the {@link ClassResolver} which will load the class
* of the serialized object
*/
public ObjectDecoder(int maxObjectSize, ClassResolver classResolver) {
super(maxObjectSize, 0, 4, 0, 4);
this.classResolver = classResolver;
}
/**
* Create a new decoder with the specified maximum object size and the {@link ClassLoader} wrapped in {@link ClassResolvers#weakCachingResolver(ClassLoader)}
*
* @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 the classloader to use
* @deprecated use {@link #ObjectDecoder(int, ClassResolver)}
*/
@Deprecated
public ObjectDecoder(int maxObjectSize, ClassLoader classLoader) {
this(maxObjectSize, ClassResolvers.weakCachingResolver(classLoader));
}
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {
ChannelBuffer frame = (ChannelBuffer) super.decode(ctx, channel, buffer);
if (frame == null) {
return null;
}
return new CompactObjectInputStream(
new ChannelBufferInputStream(frame), classResolver).readObject();
}
@Override
protected ChannelBuffer extractFrame(ChannelBuffer buffer, int index, int length) {
return buffer.slice(index, length);
}
}