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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, 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.classification.InterfaceAudience;
25  import org.apache.hadoop.hbase.classification.InterfaceStability;
26  import org.apache.hadoop.hbase.Cell;
27  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
28  import org.apache.hadoop.hbase.KeyValue;
29  import org.apache.hadoop.hbase.KeyValueUtil;
30  
31  /**
32   * Codec that does KeyValue version 1 serialization with serializing tags also.
33   *
34   * <p>
35   * Encodes by casting Cell to KeyValue and writing out the backing array with a length prefix. This
36   * is how KVs were serialized in Puts, Deletes and Results pre-0.96. Its what would happen if you
37   * called the Writable#write KeyValue implementation. This encoder will fail if the passed Cell is
38   * not an old-school pre-0.96 KeyValue. Does not copy bytes writing. It just writes them direct to
39   * the passed stream.
40   *
41   * <p>
42   * If you wrote two KeyValues to this encoder, it would look like this in the stream:
43   *
44   * <pre>
45   * length-of-KeyValue1 // A java int with the length of KeyValue1 backing array
46   * KeyValue1 backing array filled with a KeyValue serialized in its particular format
47   * length-of-KeyValue2
48   * KeyValue2 backing array
49   * </pre>
50   *
51   * Note: The only difference of this with KeyValueCodec is the latter ignores tags in KeyValues.
52   * <b>Use this Codec only at server side.</b>
53   */
54  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
55  @InterfaceStability.Unstable
56  public class KeyValueCodecWithTags implements Codec {
57    public static class KeyValueEncoder extends BaseEncoder {
58      public KeyValueEncoder(final OutputStream out) {
59        super(out);
60      }
61  
62      @Override
63      public void write(Cell cell) throws IOException {
64        checkFlushed();
65        // This is crass and will not work when KV changes. Also if passed a non-kv Cell, it will
66        // make expensive copy.
67        // Write tags
68        KeyValue.oswrite((KeyValue) KeyValueUtil.ensureKeyValue(cell), this.out, true);
69      }
70    }
71  
72    public static class KeyValueDecoder extends BaseDecoder {
73      public KeyValueDecoder(final InputStream in) {
74        super(in);
75      }
76  
77      protected Cell parseCell() throws IOException {
78        return KeyValue.iscreate(in);
79      }
80    }
81  
82    /**
83     * Implementation depends on {@link InputStream#available()}
84     */
85    @Override
86    public Decoder getDecoder(final InputStream is) {
87      return new KeyValueDecoder(is);
88    }
89  
90    @Override
91    public Encoder getEncoder(OutputStream os) {
92      return new KeyValueEncoder(os);
93    }
94  }