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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.core.buffer.BufferDataException;
25  import org.apache.mina.core.buffer.IoBuffer;
26  import org.apache.mina.core.session.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 IoBuffer#getObject(ClassLoader)}.
34   *
35   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
36   */
37  public class ObjectSerializationDecoder extends CumulativeProtocolDecoder {
38      private final ClassLoader classLoader;
39  
40      private int maxObjectSize = 1048576; // 1MB
41  
42      /**
43       * Creates a new instance with the {@link ClassLoader} of
44       * the current thread.
45       */
46      public ObjectSerializationDecoder() {
47          this(Thread.currentThread().getContextClassLoader());
48      }
49  
50      /**
51       * Creates a new instance with the specified {@link ClassLoader}.
52       */
53      public ObjectSerializationDecoder(ClassLoader classLoader) {
54          if (classLoader == null) {
55              throw new IllegalArgumentException("classLoader");
56          }
57          this.classLoader = classLoader;
58      }
59  
60      /**
61       * Returns the allowed maximum size of the object to be decoded.
62       * If the size of the object to be decoded exceeds this value, this
63       * decoder will throw a {@link BufferDataException}.  The default
64       * value is <tt>1048576</tt> (1MB).
65       */
66      public int getMaxObjectSize() {
67          return maxObjectSize;
68      }
69  
70      /**
71       * Sets the allowed maximum size of the object to be decoded.
72       * If the size of the object to be decoded exceeds this value, this
73       * decoder will throw a {@link BufferDataException}.  The default
74       * value is <tt>1048576</tt> (1MB).
75       */
76      public void setMaxObjectSize(int maxObjectSize) {
77          if (maxObjectSize <= 0) {
78              throw new IllegalArgumentException("maxObjectSize: " + maxObjectSize);
79          }
80  
81          this.maxObjectSize = maxObjectSize;
82      }
83  
84      @Override
85      protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
86          if (!in.prefixedDataAvailable(4, maxObjectSize)) {
87              return false;
88          }
89  
90          out.write(in.getObject(classLoader));
91          return true;
92      }
93  }