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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.mina.filter.codec.serialization;
21  
22  import java.io.Serializable;
23  
24  import org.apache.mina.common.BufferDataException;
25  import org.apache.mina.common.ByteBuffer;
26  import org.apache.mina.common.IoSession;
27  import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
28  import org.apache.mina.filter.codec.ProtocolDecoder;
29  import org.apache.mina.filter.codec.ProtocolDecoderOutput;
30  
31  /**
32   * A {@link ProtocolDecoder} which deserializes {@link Serializable} Java
33   * objects using {@link ByteBuffer#getObject(ClassLoader)}.
34   *
35   * @author The Apache Directory Project (mina-dev@directory.apache.org)
36   * @version $Rev: 555855 $, $Date: 2007-07-13 12:19:00 +0900 (Fri, 13 Jul 2007) $
37   */
38  public class ObjectSerializationDecoder extends CumulativeProtocolDecoder {
39      private final ClassLoader classLoader;
40  
41      private int maxObjectSize = 1048576; // 1MB
42  
43      /**
44       * Creates a new instance with the {@link ClassLoader} of
45       * the current thread.
46       */
47      public ObjectSerializationDecoder() {
48          this(Thread.currentThread().getContextClassLoader());
49      }
50  
51      /**
52       * Creates a new instance with the specified {@link ClassLoader}.
53       */
54      public ObjectSerializationDecoder(ClassLoader classLoader) {
55          if (classLoader == null) {
56              throw new NullPointerException("classLoader");
57          }
58          this.classLoader = classLoader;
59      }
60  
61      /**
62       * Returns the allowed maximum size of the object to be decoded.
63       * If the size of the object to be decoded exceeds this value, this
64       * decoder will throw a {@link BufferDataException}.  The default
65       * value is <tt>1048576</tt> (1MB).
66       */
67      public int getMaxObjectSize() {
68          return maxObjectSize;
69      }
70  
71      /**
72       * Sets the allowed maximum size of the object to be decoded.
73       * If the size of the object to be decoded exceeds this value, this
74       * decoder will throw a {@link BufferDataException}.  The default
75       * value is <tt>1048576</tt> (1MB).
76       */
77      public void setMaxObjectSize(int maxObjectSize) {
78          if (maxObjectSize <= 0) {
79              throw new IllegalArgumentException("maxObjectSize: "
80                      + maxObjectSize);
81          }
82  
83          this.maxObjectSize = maxObjectSize;
84      }
85  
86      protected boolean doDecode(IoSession session, ByteBuffer in,
87              ProtocolDecoderOutput out) throws Exception {
88          if (!in.prefixedDataAvailable(4, maxObjectSize)) {
89              return false;
90          }
91  
92          out.write(in.getObject(classLoader));
93          return true;
94      }
95  }