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/*
* Copyright 2000-2013 JetBrains s.r.o.
*
* Licensed 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 com.intellij.openapi.util;
import com.intellij.openapi.Disposable;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.util.ConcurrencyUtil;
import com.intellij.util.containers.WeakList;
import javax.management.Notification;
import javax.management.NotificationEmitter;
import javax.management.NotificationListener;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryNotificationInfo;
import java.lang.management.MemoryPoolMXBean;
import java.lang.management.MemoryType;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
* @author Eugene Zhuravlev
* Date: Aug 24, 2010
*/
public class LowMemoryWatcher {
private static final long MEM_THRESHOLD = 5 /*MB*/ * 1024 * 1024;
private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.util.LowMemoryWatcher");
private static final List<LowMemoryWatcher> ourInstances = new WeakList<LowMemoryWatcher>();
private static final ThreadPoolExecutor ourExecutor = new ThreadPoolExecutor(0, 1, 10, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(2), ConcurrencyUtil.newNamedThreadFactory("LowMemoryWatcher janitor"));
private static boolean ourSubmitted;
private static final Runnable ourJanitor = new Runnable() {
@Override
public void run() {
try {
for (LowMemoryWatcher watcher : ourInstances) {
try {
watcher.myRunnable.run();
}
catch (Throwable e) {
LOG.info(e);
}
}
}
finally {
synchronized (ourJanitor) {
//noinspection AssignmentToStaticFieldFromInstanceMethod
ourSubmitted = false;
}
}
}
};
private final Runnable myRunnable;
static {
for (MemoryPoolMXBean bean : ManagementFactory.getMemoryPoolMXBeans()) {
if (bean.getType() == MemoryType.HEAP && bean.isUsageThresholdSupported()) {
long threshold = bean.getUsage().getMax() - MEM_THRESHOLD;
if (threshold > 0) {
bean.setUsageThreshold(threshold);
bean.setCollectionUsageThreshold(threshold);
}
}
}
((NotificationEmitter)ManagementFactory.getMemoryMXBean()).addNotificationListener(new NotificationListener() {
@Override
public void handleNotification(Notification n, Object hb) {
if (MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED.equals(n.getType()) || MemoryNotificationInfo.MEMORY_COLLECTION_THRESHOLD_EXCEEDED.equals(n.getType())) {
synchronized (ourJanitor) {
if (!ourSubmitted) {
//noinspection AssignmentToStaticFieldFromInstanceMethod
ourSubmitted = true;
ourExecutor.submit(ourJanitor);
}
}
}
}
}, null, null);
}
/**
* Registers a runnable to run on low memory events
* @return a LowMemoryWatcher instance holding the runnable. This instance should be kept in memory while the
* low memory notification functionality is needed. As soon as it's garbage-collected, the runnable won't receive any further notifications.
*/
public static LowMemoryWatcher register(Runnable runnable) {
return new LowMemoryWatcher(runnable);
}
/**
* Registers a runnable to run on low memory events. The notifications will be issued until parentDisposable is disposed.
*/
public static void register(Runnable runnable, Disposable parentDisposable) {
final Ref<LowMemoryWatcher> watcher = Ref.create(new LowMemoryWatcher(runnable));
Disposer.register(parentDisposable, new Disposable() {
@Override
public void dispose() {
watcher.get().stop();
watcher.set(null);
}
});
}
private LowMemoryWatcher(Runnable runnable) {
myRunnable = runnable;
ourInstances.add(this);
}
public void stop() {
ourInstances.remove(this);
}
}
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