1 /***
2 *
3 * Copyright 2004 Hiram Chirino
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 **/
18 package org.codehaus.activemq.journal.impl;
19
20 import java.io.DataInput;
21 import java.io.DataOutput;
22 import java.io.IOException;
23 import java.nio.ByteBuffer;
24
25 /***
26 * Serializes/Deserializes record header information.
27 *
28 * @version $Revision: 1.2 $
29 */
30 public class RecordHeader {
31 static final public int RECORD_HEADER_SIZE=16;
32 static final public byte[] START_OF_RECORD = new byte[] { 'S', 'o', 'R' };
33
34 public int length;
35 public long sequenceId;
36 public byte recordType;
37
38 /***
39 * @return
40 */
41 public ByteBuffer toByteBuffer() {
42 ByteBuffer buff = ByteBuffer.allocate(RECORD_HEADER_SIZE);
43 buff.put(START_OF_RECORD)
44 .putInt(length)
45 .putLong(sequenceId)
46 .put(recordType)
47 .flip();
48 return buff;
49 }
50
51 void writeRecordHeader( DataOutput out ) throws IOException {
52 out.write(START_OF_RECORD);
53 out.writeInt(length);
54 out.writeLong(sequenceId);
55 out.writeByte(recordType);
56 }
57
58 void readRecordHeader( DataInput in ) throws IOException {
59 for (int i = 0; i < START_OF_RECORD.length; i++) {
60 byte checkByte = START_OF_RECORD[i];
61 if( in.readByte()!= checkByte ) {
62 throw new IOException("Not a valid record header.");
63 }
64 }
65 length = in.readInt();
66 sequenceId = in.readLong();
67 recordType = in.readByte();
68 }
69
70 /***
71 *
72 */
73 public void invalidate() {
74 length=-1;
75 sequenceId=-1;
76 }
77
78 public boolean isValid() {
79 return length>=0;
80 }
81
82 /***
83 * @param recordType2
84 * @param sequenceId2
85 * @param data
86 */
87 public void bulkSet(byte recordType, long sequenceId, byte[] data) {
88 this.length = data.length;
89 this.sequenceId = sequenceId;
90 this.recordType = recordType;
91 }
92
93 }