View Javadoc

    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.codec.delimited;
    21
    22  import java.nio.ByteBuffer;
    23
    24  import org.apache.mina.codec.StatelessProtocolEncoder;
    25
    26  /**
    27   *
    28   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
    29   */
    30  public class SizePrefixedEncoder<IN> implements StatelessProtocolEncoder<IN, ByteBuffer> {
    31
    32      private final ByteBufferEncoder<Integer> sizeEncoder;
    33
    34      private final ByteBufferEncoder<IN> payloadEncoder;
    35
    36      public SizePrefixedEncoder(ByteBufferEncoder<Integer> sizeEncoder, ByteBufferEncoder<IN> payloadEncoder) {
    37          super();
    38          this.sizeEncoder = sizeEncoder;
    39          this.payloadEncoder = payloadEncoder;
    40      }
    41
    42      @Override
    43      public Void createEncoderState() {
    44          // stateless!
    45          return null;
    46      }
    47
    48      @Override
    49      public ByteBuffer encode(IN message, Void context) {
    50          int messageSize = payloadEncoder.getEncodedSize(message);
    51          ByteBuffer buffer = ByteBuffer.allocate(sizeEncoder.getEncodedSize(messageSize) + messageSize);
    52
    53          sizeEncoder.writeTo(messageSize, buffer);
    54          payloadEncoder.writeTo(message, buffer);
    55
    56          buffer.flip();
    57          return buffer;
    58      }
    59
    60  }