1 /*
2 *
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19 package org.apache.hadoop.hbase.io.hfile;
20
21 import java.io.DataOutput;
22 import java.io.IOException;
23
24 import org.apache.hadoop.hbase.classification.InterfaceAudience;
25
26 /**
27 * A way to write "inline" blocks into an {@link HFile}. Inline blocks are
28 * interspersed with data blocks. For example, Bloom filter chunks and
29 * leaf-level blocks of a multi-level block index are stored as inline blocks.
30 */
31 @InterfaceAudience.Private
32 public interface InlineBlockWriter {
33
34 /**
35 * Determines whether there is a new block to be written out.
36 *
37 * @param closing
38 * whether the file is being closed, in which case we need to write
39 * out all available data and not wait to accumulate another block
40 */
41 boolean shouldWriteBlock(boolean closing);
42
43 /**
44 * Writes the block to the provided stream. Must not write any magic records.
45 * Called only if {@link #shouldWriteBlock(boolean)} returned true.
46 *
47 * @param out
48 * a stream (usually a compressing stream) to write the block to
49 */
50 void writeInlineBlock(DataOutput out) throws IOException;
51
52 /**
53 * Called after a block has been written, and its offset, raw size, and
54 * compressed size have been determined. Can be used to add an entry to a
55 * block index. If this type of inline blocks needs a block index, the inline
56 * block writer is responsible for maintaining it.
57 *
58 * @param offset the offset of the block in the stream
59 * @param onDiskSize the on-disk size of the block
60 * @param uncompressedSize the uncompressed size of the block
61 */
62 void blockWritten(long offset, int onDiskSize, int uncompressedSize);
63
64 /**
65 * The type of blocks this block writer produces.
66 */
67 BlockType getInlineBlockType();
68
69 /**
70 * @return true if inline blocks produced by this writer should be cached
71 */
72 boolean getCacheOnWrite();
73 }