1 /**
2 * Copyright The Apache Software Foundation
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with this
6 * work for additional information regarding copyright ownership. The ASF
7 * licenses this file to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance with the License.
9 * 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, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
16 * License for the specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.hadoop.hbase.io.hfile.bucket;
20
21 import java.io.IOException;
22 import java.nio.ByteBuffer;
23
24 import org.apache.hadoop.classification.InterfaceAudience;
25 import org.apache.hadoop.hbase.util.ByteBufferArray;
26
27 /**
28 * IO engine that stores data on the memory using an array of ByteBuffers
29 * {@link ByteBufferArray}
30 */
31 @InterfaceAudience.Private
32 public class ByteBufferIOEngine implements IOEngine {
33
34 private ByteBufferArray bufferArray;
35
36 /**
37 * Construct the ByteBufferIOEngine with the given capacity
38 * @param capacity
39 * @param direct true if allocate direct buffer
40 * @throws IOException
41 */
42 public ByteBufferIOEngine(long capacity, boolean direct)
43 throws IOException {
44 bufferArray = new ByteBufferArray(capacity, direct);
45 }
46
47 /**
48 * Memory IO engine is always unable to support persistent storage for the
49 * cache
50 * @return false
51 */
52 @Override
53 public boolean isPersistent() {
54 return false;
55 }
56
57 /**
58 * Transfers data from the buffer array to the given byte buffer
59 * @param dstBuffer the given byte buffer into which bytes are to be written
60 * @param offset The offset in the ByteBufferArray of the first byte to be
61 * read
62 * @throws IOException
63 */
64 @Override
65 public void read(ByteBuffer dstBuffer, long offset) throws IOException {
66 assert dstBuffer.hasArray();
67 bufferArray.getMultiple(offset, dstBuffer.remaining(), dstBuffer.array(),
68 dstBuffer.arrayOffset());
69 }
70
71 /**
72 * Transfers data from the given byte buffer to the buffer array
73 * @param srcBuffer the given byte buffer from which bytes are to be read
74 * @param offset The offset in the ByteBufferArray of the first byte to be
75 * written
76 * @throws IOException
77 */
78 @Override
79 public void write(ByteBuffer srcBuffer, long offset) throws IOException {
80 assert srcBuffer.hasArray();
81 bufferArray.putMultiple(offset, srcBuffer.remaining(), srcBuffer.array(),
82 srcBuffer.arrayOffset());
83 }
84
85 /**
86 * No operation for the sync in the memory IO engine
87 */
88 @Override
89 public void sync() {
90
91 }
92
93 /**
94 * No operation for the shutdown in the memory IO engine
95 */
96 @Override
97 public void shutdown() {
98
99 }
100 }