001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with this
004 * work for additional information regarding copyright ownership. The ASF
005 * licenses this file to you under the Apache License, Version 2.0 (the
006 * "License"); you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
013 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
014 * License for the specific language governing permissions and limitations
015 * under the License.
016 */
017package org.apache.hadoop.hbase.io.hfile.bucket;
018
019import java.io.IOException;
020
021import org.apache.hadoop.hbase.io.hfile.Cacheable;
022import org.apache.hadoop.hbase.nio.ByteBuff;
023import org.apache.yetus.audience.InterfaceAudience;
024
025/**
026 * IO engine that stores data to a file on the local block device using memory mapping mechanism
027 */
028@InterfaceAudience.Private
029public class ExclusiveMemoryMmapIOEngine extends FileMmapIOEngine {
030
031  public ExclusiveMemoryMmapIOEngine(String filePath, long capacity) throws IOException {
032    super(filePath, capacity);
033  }
034
035  @Override
036  public Cacheable read(BucketEntry be) throws IOException {
037    ByteBuff dst = be.allocator.allocate(be.getLength());
038    bufferArray.read(be.offset(), dst);
039    dst.position(0).limit(be.getLength());
040    return be.wrapAsCacheable(dst);
041  }
042}