001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.mina.filter.codec.serialization;
021
022import java.io.Serializable;
023
024import org.apache.mina.core.buffer.BufferDataException;
025import org.apache.mina.core.buffer.IoBuffer;
026import org.apache.mina.core.session.IoSession;
027import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
028import org.apache.mina.filter.codec.ProtocolDecoder;
029import org.apache.mina.filter.codec.ProtocolDecoderOutput;
030
031/**
032 * A {@link ProtocolDecoder} which deserializes {@link Serializable} Java
033 * objects using {@link IoBuffer#getObject(ClassLoader)}.
034 *
035 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
036 */
037public class ObjectSerializationDecoder extends CumulativeProtocolDecoder {
038    private final ClassLoader classLoader;
039
040    private int maxObjectSize = 1048576; // 1MB
041
042    /**
043     * Creates a new instance with the {@link ClassLoader} of
044     * the current thread.
045     */
046    public ObjectSerializationDecoder() {
047        this(Thread.currentThread().getContextClassLoader());
048    }
049
050    /**
051     * Creates a new instance with the specified {@link ClassLoader}.
052     * 
053     * @param classLoader The class loader to use
054     */
055    public ObjectSerializationDecoder(ClassLoader classLoader) {
056        if (classLoader == null) {
057            throw new IllegalArgumentException("classLoader");
058        }
059        this.classLoader = classLoader;
060    }
061
062    /**
063     * @return the allowed maximum size of the object to be decoded.
064     * If the size of the object to be decoded exceeds this value, this
065     * decoder will throw a {@link BufferDataException}.  The default
066     * value is <tt>1048576</tt> (1MB).
067     */
068    public int getMaxObjectSize() {
069        return maxObjectSize;
070    }
071
072    /**
073     * Sets the allowed maximum size of the object to be decoded.
074     * If the size of the object to be decoded exceeds this value, this
075     * decoder will throw a {@link BufferDataException}.  The default
076     * value is <tt>1048576</tt> (1MB).
077     * 
078     * @param maxObjectSize The maximum size for an object to be decoded
079     */
080    public void setMaxObjectSize(int maxObjectSize) {
081        if (maxObjectSize <= 0) {
082            throw new IllegalArgumentException("maxObjectSize: " + maxObjectSize);
083        }
084
085        this.maxObjectSize = maxObjectSize;
086    }
087
088    /**
089     * {@inheritDoc}
090     */
091    @Override
092    protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
093        if (!in.prefixedDataAvailable(4, maxObjectSize)) {
094            return false;
095        }
096
097        out.write(in.getObject(classLoader));
098        return true;
099    }
100}