| /** |
| * 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.activemq.memory; |
| |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.concurrent.CopyOnWriteArrayList; |
| |
| import org.apache.activemq.thread.Task; |
| import org.apache.activemq.thread.TaskRunner; |
| import org.apache.activemq.thread.TaskRunnerFactory; |
| import org.apache.activemq.usage.Usage; |
| import org.apache.activemq.usage.UsageListener; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| public class CacheEvictionUsageListener implements UsageListener { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(CacheEvictionUsageListener.class); |
| |
| private final List<CacheEvictor> evictors = new CopyOnWriteArrayList<CacheEvictor>(); |
| private final int usageHighMark; |
| private final int usageLowMark; |
| |
| private final TaskRunner evictionTask; |
| private final Usage usage; |
| |
| public CacheEvictionUsageListener(Usage usage, int usageHighMark, int usageLowMark, TaskRunnerFactory taskRunnerFactory) { |
| this.usage = usage; |
| this.usageHighMark = usageHighMark; |
| this.usageLowMark = usageLowMark; |
| evictionTask = taskRunnerFactory.createTaskRunner(new Task() { |
| public boolean iterate() { |
| return evictMessages(); |
| } |
| }, "Cache Evictor: " + System.identityHashCode(this)); |
| } |
| |
| boolean evictMessages() { |
| // Try to take the memory usage down below the low mark. |
| LOG.debug("Evicting cache memory usage: " + usage.getPercentUsage()); |
| |
| List<CacheEvictor> list = new LinkedList<CacheEvictor>(evictors); |
| while (list.size() > 0 && usage.getPercentUsage() > usageLowMark) { |
| |
| // Evenly evict messages from all evictors |
| for (Iterator<CacheEvictor> iter = list.iterator(); iter.hasNext();) { |
| CacheEvictor evictor = iter.next(); |
| if (evictor.evictCacheEntry() == null) { |
| iter.remove(); |
| } |
| } |
| } |
| return false; |
| } |
| |
| public void onUsageChanged(Usage usage, int oldPercentUsage, int newPercentUsage) { |
| // Do we need to start evicting cache entries? Usage > than the |
| // high mark |
| if (oldPercentUsage < newPercentUsage && usage.getPercentUsage() >= usageHighMark) { |
| try { |
| evictionTask.wakeup(); |
| } catch (InterruptedException e) { |
| Thread.currentThread().interrupt(); |
| } |
| } |
| } |
| |
| public void add(CacheEvictor evictor) { |
| evictors.add(evictor); |
| } |
| |
| public void remove(CacheEvictor evictor) { |
| evictors.remove(evictor); |
| } |
| } |