View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with this
4    * work for additional information regarding copyright ownership. The ASF
5    * licenses this file to you under the Apache License, Version 2.0 (the
6    * "License"); 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, WITHOUT
13   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
14   * License for the specific language governing permissions and limitations
15   * under the License.
16   */
17  package org.apache.hadoop.hbase.io.encoding;
18  
19  import java.io.IOException;
20  import java.io.OutputStream;
21  
22  import org.apache.hadoop.classification.InterfaceAudience;
23  import org.apache.hadoop.hbase.io.hfile.BlockType;
24  import org.apache.hadoop.hbase.io.hfile.HFileContext;
25  
26  /**
27   * An encoding context that is created by a writer's encoder, and is shared
28   * across the writer's whole lifetime.
29   *
30   * @see HFileBlockDecodingContext for decoding
31   *
32   */
33  @InterfaceAudience.Private
34  public interface HFileBlockEncodingContext {
35  
36    /**
37     * @return OutputStream to which encoded data is written
38     */
39    OutputStream getOutputStreamForEncoder();
40  
41    /**
42     * @return encoded and compressed bytes with header which are ready to write
43     *         out to disk
44     */
45    byte[] getOnDiskBytesWithHeader();
46  
47    /**
48     * @return encoded but not heavily compressed bytes with header which can be
49     *         cached in block cache
50     */
51    byte[] getUncompressedBytesWithHeader();
52  
53    /**
54     * @return the block type after encoding
55     */
56    BlockType getBlockType();
57  
58    /**
59     * sets the dummy header bytes
60     */
61    void setDummyHeader(byte[] headerBytes);
62  
63    /**
64     * @return the {@link DataBlockEncoding} encoding used
65     */
66    DataBlockEncoding getDataBlockEncoding();
67  
68    /**
69     * Do any action that needs to be performed after the encoding.
70     * Compression is also included if a non-null compression algorithm is used
71     *
72     * @param blockType
73     * @throws IOException
74     */
75    void postEncoding(BlockType blockType) throws IOException;
76  
77    /**
78     * Releases the resources used.
79     */
80    void close();
81  
82    /**
83     * @return HFile context information
84     */
85    HFileContext getHFileContext();
86  }