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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  }