001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. 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, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.activemq.memory; 018 019 import java.util.concurrent.atomic.AtomicLong; 020 import org.apache.activemq.usage.MemoryUsage; 021 022 /** 023 * Simple CacheFilter that increases/decreases usage on a UsageManager as 024 * objects are added/removed from the Cache. 025 * 026 * 027 */ 028 public class UsageManagerCacheFilter extends CacheFilter { 029 030 private final AtomicLong totalUsage = new AtomicLong(0); 031 private final MemoryUsage usage; 032 033 public UsageManagerCacheFilter(Cache next, MemoryUsage um) { 034 super(next); 035 this.usage = um; 036 } 037 038 public Object put(Object key, Object value) { 039 long usageValue = getUsageOfAddedObject(value); 040 Object rc = super.put(key, value); 041 if (rc != null) { 042 usageValue -= getUsageOfRemovedObject(rc); 043 } 044 totalUsage.addAndGet(usageValue); 045 usage.increaseUsage(usageValue); 046 return rc; 047 } 048 049 public Object remove(Object key) { 050 Object rc = super.remove(key); 051 if (rc != null) { 052 long usageValue = getUsageOfRemovedObject(rc); 053 totalUsage.addAndGet(-usageValue); 054 usage.decreaseUsage(usageValue); 055 } 056 return rc; 057 } 058 059 protected long getUsageOfAddedObject(Object value) { 060 return 1; 061 } 062 063 protected long getUsageOfRemovedObject(Object value) { 064 return 1; 065 } 066 067 public void close() { 068 usage.decreaseUsage(totalUsage.get()); 069 } 070 }