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 }