| /* |
| * 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.codehaus.groovy.util; |
| |
| import java.lang.ref.ReferenceQueue; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| public class ReferenceManager { |
| private static class ThreadedReferenceManager extends ReferenceManager { |
| private final Thread thread; |
| private volatile boolean shouldRun = true; |
| public ThreadedReferenceManager(ReferenceQueue queue) { |
| super(queue); |
| thread = new Thread() { |
| public void run() { |
| ReferenceQueue queue = getReferenceQueue(); |
| java.lang.ref.Reference r=null; |
| while (shouldRun) { |
| try { |
| r = queue.remove(1000); |
| } catch (InterruptedException e) { |
| break; |
| } |
| if (r==null) continue; |
| |
| if (r instanceof Reference) { |
| Reference ref = (Reference) r; |
| Finalizable holder = ref.getHandler(); |
| if (holder!=null) holder.finalizeReference(); |
| } |
| r.clear(); |
| r=null; |
| } |
| } |
| }; |
| thread.setContextClassLoader(null); |
| thread.setDaemon(true); |
| thread.setName(ThreadedReferenceManager.class.getName()); |
| thread.start(); |
| } |
| @Override |
| public void stopThread() { |
| shouldRun = false; |
| thread.interrupt(); |
| } |
| @Override |
| public String toString() { |
| return "ReferenceManager(threaded, thread="+thread+")"; |
| } |
| } |
| |
| public static ReferenceManager createThreadedManager(ReferenceQueue queue) { |
| return new ThreadedReferenceManager(queue); |
| } |
| public static ReferenceManager createIdlingManager(ReferenceQueue queue) { |
| return new ReferenceManager(queue); |
| } |
| public static ReferenceManager createCallBackedManager(ReferenceQueue queue) { |
| return new CallBackedManager(queue); |
| } |
| |
| private static class CallBackedManager extends ReferenceManager { |
| |
| private static final ConcurrentHashMap<ReferenceQueue, ReferenceManager> queuesInProcess = |
| new ConcurrentHashMap<ReferenceQueue, ReferenceManager>(4, 0.9f, 2); |
| |
| public CallBackedManager(ReferenceQueue queue) { |
| super(queue); |
| } |
| |
| @Override |
| public void removeStallEntries() { |
| ReferenceQueue queue = getReferenceQueue(); |
| if (queuesInProcess.putIfAbsent(queue, this) == null) { |
| try { |
| removeStallEntries0(queue); |
| } finally { |
| queuesInProcess.remove(queue); |
| } |
| } |
| } |
| |
| private static void removeStallEntries0(ReferenceQueue queue) { |
| for(;;) { |
| java.lang.ref.Reference r = queue.poll(); |
| if (r==null) break; |
| |
| if (r instanceof Reference) { |
| Reference ref = (Reference) r; |
| Finalizable holder = ref.getHandler(); |
| if (holder!=null) holder.finalizeReference(); |
| } |
| r.clear(); |
| r=null; |
| } |
| } |
| |
| @Override |
| public void afterReferenceCreation(Reference r) { |
| removeStallEntries(); |
| } |
| |
| @Override |
| public String toString() { |
| return "ReferenceManager(callback)"; |
| } |
| } |
| |
| public static ReferenceManager createThresholdedIdlingManager(final ReferenceQueue queue, final ReferenceManager callback, final int threshold) { |
| if (threshold<0) throw new IllegalArgumentException("threshold must not be below 0."); |
| |
| return new ReferenceManager(queue){ |
| private AtomicInteger refCnt = new AtomicInteger(); |
| private volatile ReferenceManager manager = createIdlingManager(queue); |
| @Override |
| public void afterReferenceCreation(Reference r) { |
| if (manager==callback) { |
| callback.afterReferenceCreation(r); |
| return; |
| } |
| // we use the idle manager, so let us use the reference counter |
| // we change the manager once the threshold is reached. There is |
| // a small chance that the value will go beyond Integer.MAX_VALUE |
| // so we check for values below 0 too. If threshold is low, then |
| // this is unlikely to happen. If threshold is high, then we |
| // have all negative values as fall back |
| int count = refCnt.incrementAndGet(); |
| if (count>threshold || count<0) { |
| manager = callback; |
| callback.afterReferenceCreation(r); |
| } |
| } |
| @Override |
| public void removeStallEntries() { |
| manager.removeStallEntries(); |
| } |
| @Override |
| public void stopThread() { |
| manager.stopThread(); |
| } |
| @Override |
| public String toString() { |
| return "ReferenceManager(thresholded, current manager="+manager+", threshold="+refCnt.get()+"/"+threshold+")"; |
| } |
| }; |
| } |
| |
| private ReferenceQueue queue; |
| |
| public ReferenceManager(ReferenceQueue queue) { |
| this.queue = queue; |
| } |
| |
| protected ReferenceQueue getReferenceQueue() { |
| return queue; |
| } |
| |
| public void afterReferenceCreation(Reference r) {} |
| public void removeStallEntries() {} |
| public void stopThread() {} |
| |
| @Override |
| public String toString() { |
| return "ReferenceManager(idling)"; |
| } |
| |
| /** |
| * @deprecated use {@link ReferenceBundle#getSoftBundle()} |
| */ |
| @Deprecated |
| public static ReferenceBundle getDefaultSoftBundle() { |
| return ReferenceBundle.getSoftBundle(); |
| } |
| |
| /** |
| * @deprecated use {@link ReferenceBundle#getWeakBundle()} |
| */ |
| @Deprecated |
| public static ReferenceBundle getDefaultWeakBundle() { |
| return ReferenceBundle.getWeakBundle(); |
| } |
| } |