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 }