| /** |
| * Copyright 2008 The Apache Software Foundation |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hbase.io.hfile; |
| |
| import java.lang.ref.ReferenceQueue; |
| import java.lang.ref.SoftReference; |
| import java.nio.ByteBuffer; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| |
| /** |
| * Simple one RFile soft reference cache. |
| */ |
| public class SimpleBlockCache implements BlockCache { |
| private static class Ref extends SoftReference<ByteBuffer> { |
| public String blockId; |
| public Ref(String blockId, ByteBuffer buf, ReferenceQueue q) { |
| super(buf, q); |
| this.blockId = blockId; |
| } |
| } |
| private Map<String,Ref> cache = |
| new HashMap<String,Ref>(); |
| |
| private ReferenceQueue q = new ReferenceQueue(); |
| public int dumps = 0; |
| |
| /** |
| * Constructor |
| */ |
| public SimpleBlockCache() { |
| super(); |
| } |
| |
| void processQueue() { |
| Ref r; |
| while ( (r = (Ref)q.poll()) != null) { |
| cache.remove(r.blockId); |
| dumps++; |
| } |
| } |
| |
| /** |
| * @return the size |
| */ |
| public synchronized int size() { |
| processQueue(); |
| return cache.size(); |
| } |
| |
| public synchronized ByteBuffer getBlock(String blockName, boolean caching) { |
| processQueue(); // clear out some crap. |
| Ref ref = cache.get(blockName); |
| if (ref == null) |
| return null; |
| return ref.get(); |
| } |
| |
| public synchronized void cacheBlock(String blockName, ByteBuffer buf) { |
| cache.put(blockName, new Ref(blockName, buf, q)); |
| } |
| |
| public synchronized void cacheBlock(String blockName, ByteBuffer buf, |
| boolean inMemory) { |
| cache.put(blockName, new Ref(blockName, buf, q)); |
| } |
| |
| public void shutdown() { |
| // noop |
| } |
| } |