001/** 002 * 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, software 014 * distributed under the License is distributed on an "AS IS" BASIS, 015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 016 * See the License for the specific language governing permissions and 017 * limitations under the License. 018 */ 019package org.apache.hadoop.hbase.mob; 020 021import java.io.IOException; 022import java.util.concurrent.atomic.AtomicLong; 023 024import org.apache.hadoop.conf.Configuration; 025import org.apache.hadoop.fs.FileSystem; 026import org.apache.hadoop.fs.Path; 027import org.apache.hadoop.hbase.io.hfile.CacheConfig; 028import org.apache.hadoop.hbase.regionserver.BloomType; 029import org.apache.hadoop.hbase.regionserver.HStoreFile; 030import org.apache.yetus.audience.InterfaceAudience; 031 032/** 033 * Cached mob file. 034 */ 035@InterfaceAudience.Private 036public class CachedMobFile extends MobFile implements Comparable<CachedMobFile> { 037 038 private long accessCount; 039 private AtomicLong referenceCount = new AtomicLong(0); 040 041 public CachedMobFile(HStoreFile sf) { 042 super(sf); 043 } 044 045 public static CachedMobFile create(FileSystem fs, Path path, Configuration conf, 046 CacheConfig cacheConf) throws IOException { 047 // XXX: primaryReplica is only used for constructing the key of block cache so it is not a 048 // critical problem if we pass the wrong value, so here we always pass true. Need to fix later. 049 HStoreFile sf = new HStoreFile(fs, path, conf, cacheConf, BloomType.NONE, true); 050 return new CachedMobFile(sf); 051 } 052 053 public void access(long accessCount) { 054 this.accessCount = accessCount; 055 } 056 057 @Override 058 public int compareTo(CachedMobFile that) { 059 if (this.accessCount == that.accessCount) return 0; 060 return this.accessCount < that.accessCount ? 1 : -1; 061 } 062 063 @Override 064 public boolean equals(Object obj) { 065 if (this == obj) { 066 return true; 067 } 068 if (obj == null) { 069 return false; 070 } 071 if (!(obj instanceof CachedMobFile)) { 072 return false; 073 } 074 return compareTo((CachedMobFile) obj) == 0; 075 } 076 077 @Override 078 public int hashCode() { 079 return (int)(accessCount ^ (accessCount >>> 32)); 080 } 081 082 /** 083 * Opens the mob file if it's not opened yet and increases the reference. 084 * It's not thread-safe. Use MobFileCache.openFile() instead. 085 * The reader of the mob file is just opened when it's not opened no matter how many times 086 * this open() method is invoked. 087 * The reference is a counter that how many times this reader is referenced. When the 088 * reference is 0, this reader is closed. 089 */ 090 @Override 091 public void open() throws IOException { 092 super.open(); 093 referenceCount.incrementAndGet(); 094 } 095 096 /** 097 * Decreases the reference of the underlying reader for the mob file. 098 * It's not thread-safe. Use MobFileCache.closeFile() instead. 099 * This underlying reader isn't closed until the reference is 0. 100 */ 101 @Override 102 public void close() throws IOException { 103 long refs = referenceCount.decrementAndGet(); 104 if (refs == 0) { 105 super.close(); 106 } 107 } 108 109 /** 110 * Gets the reference of the current mob file. 111 * Internal usage, currently it's for testing. 112 * @return The reference of the current mob file. 113 */ 114 public long getReferenceCount() { 115 return this.referenceCount.longValue(); 116 } 117}