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, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.hadoop.hbase.codec;
19
20 import java.io.IOException;
21 import java.io.InputStream;
22 import java.io.OutputStream;
23
24 import org.apache.hadoop.hbase.Cell;
25 import org.apache.hadoop.hbase.KeyValue;
26 import org.apache.hadoop.hbase.KeyValueUtil;
27
28 /**
29 * Codec that does KeyValue version 1 serialization.
30 *
31 * <p>Encodes by casting Cell to KeyValue and writing out the backing array with a length prefix.
32 * This is how KVs were serialized in Puts, Deletes and Results pre-0.96. Its what would
33 * happen if you called the Writable#write KeyValue implementation. This encoder will fail
34 * if the passed Cell is not an old-school pre-0.96 KeyValue. Does not copy bytes writing.
35 * It just writes them direct to the passed stream.
36 *
37 * <p>If you wrote two KeyValues to this encoder, it would look like this in the stream:
38 * <pre>
39 * length-of-KeyValue1 // A java int with the length of KeyValue1 backing array
40 * KeyValue1 backing array filled with a KeyValue serialized in its particular format
41 * length-of-KeyValue2
42 * KeyValue2 backing array
43 * </pre>
44 */
45 public class KeyValueCodec implements Codec {
46 public static class KeyValueEncoder extends BaseEncoder {
47 public KeyValueEncoder(final OutputStream out) {
48 super(out);
49 }
50
51 @Override
52 public void write(Cell cell) throws IOException {
53 checkFlushed();
54 // This is crass and will not work when KV changes. Also if passed a non-kv Cell, it will
55 // make expensive copy.
56 KeyValue.oswrite((KeyValue)KeyValueUtil.ensureKeyValue(cell), this.out);
57 }
58 }
59
60 public static class KeyValueDecoder extends BaseDecoder {
61 public KeyValueDecoder(final InputStream in) {
62 super(in);
63 }
64
65 protected Cell parseCell() throws IOException {
66 return KeyValue.iscreate(in);
67 }
68 }
69
70 /**
71 * Implementation depends on {@link InputStream#available()}
72 */
73 @Override
74 public Decoder getDecoder(final InputStream is) {
75 return new KeyValueDecoder(is);
76 }
77
78 @Override
79 public Encoder getEncoder(OutputStream os) {
80 return new KeyValueEncoder(os);
81 }
82 }