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
21 import org.apache.hadoop.hbase.classification.InterfaceAudience;
22 import org.apache.hadoop.hbase.io.hfile.HFileContext;
23 import org.apache.hadoop.hbase.nio.ByteBuff;
24
25 /**
26 * A decoding context that is created by a reader's encoder, and is shared
27 * across the reader's all read operations.
28 *
29 * @see HFileBlockEncodingContext for encoding
30 */
31 @InterfaceAudience.Private
32 public interface HFileBlockDecodingContext {
33
34 /**
35 * Perform all actions that need to be done before the encoder's real decoding
36 * process. Decompression needs to be done if
37 * {@link HFileContext#getCompression()} returns a valid compression
38 * algorithm.
39 *
40 * @param onDiskSizeWithoutHeader
41 * numBytes after block and encoding headers
42 * @param uncompressedSizeWithoutHeader
43 * numBytes without header required to store the block after
44 * decompressing (not decoding)
45 * @param blockBufferWithoutHeader
46 * ByteBuffer pointed after the header but before the data
47 * @param onDiskBlock
48 * on disk data to be decoded
49 * @throws IOException
50 */
51 void prepareDecoding(
52 int onDiskSizeWithoutHeader,
53 int uncompressedSizeWithoutHeader,
54 ByteBuff blockBufferWithoutHeader,
55 ByteBuff onDiskBlock
56 ) throws IOException;
57
58 /**
59 * @return HFile meta information
60 */
61 HFileContext getHFileContext();
62 }