/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.journal;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.log4j.Logger;
import com.bigdata.util.concurrent.ThreadPoolExecutorBaseStatisticsTask;
/**
* Plugin for sampling the {@link ExecutorService}. This collects interesting
* statistics about the thread pool for reporting to the load balancer service.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public class QueueStatsPlugIn implements
IPlugIn<Journal, ThreadPoolExecutorBaseStatisticsTask> {
private static final Logger log = Logger.getLogger(QueueStatsPlugIn.class);
/**
* Performance counters options.
*/
public interface Options {
/**
* Boolean option for the collection of statistics from the various
* queues using to run tasks (default
* {@link #DEFAULT_COLLECT_QUEUE_STATISTICS}).
*/
String COLLECT_QUEUE_STATISTICS = Journal.class.getName()
+ ".collectQueueStatistics";
String DEFAULT_COLLECT_QUEUE_STATISTICS = "false";
}
/**
* Collects interesting statistics on the {@link ExecutorService}.
* <p>
* Note: Guarded by synchronized(this).
*
* @see Options#COLLECT_QUEUE_STATISTICS
*/
private ThreadPoolExecutorBaseStatisticsTask queueSampleTask = null;
/**
* The {@link ScheduledFuture} for the task.
* <p>
* Note: Guarded by synchronized(this).
*/
private ScheduledFuture<?> scheduledFuture = null;
/**
* {@inheritDoc}
* <p>
* Setup sampling on the client's thread pool.
*/
@Override
public void startService(final Journal indexManager) {
final boolean collectQueueStatistics = Boolean.valueOf(indexManager
.getProperty(Options.COLLECT_QUEUE_STATISTICS,
Options.DEFAULT_COLLECT_QUEUE_STATISTICS));
if (log.isInfoEnabled())
log.info(Options.COLLECT_QUEUE_STATISTICS + "="
+ collectQueueStatistics);
if (!collectQueueStatistics) {
return;
}
final long initialDelay = 0; // initial delay in ms.
final long delay = 1000; // delay in ms.
final TimeUnit unit = TimeUnit.MILLISECONDS;
synchronized (this) {
queueSampleTask = new ThreadPoolExecutorBaseStatisticsTask(
(ThreadPoolExecutor) indexManager.getExecutorService());
scheduledFuture = indexManager.addScheduledTask(queueSampleTask,
initialDelay, delay, unit);
}
}
@Override
public void stopService(final boolean immediateShutdown) {
synchronized (this) {
if (scheduledFuture != null) {
scheduledFuture
.cancel(immediateShutdown/* mayInterruptIfRunning */);
scheduledFuture = null;
}
queueSampleTask = null;
}
}
@Override
public ThreadPoolExecutorBaseStatisticsTask getService() {
synchronized(this) {
return queueSampleTask;
}
}
@Override
public boolean isRunning() {
synchronized (this) {
if (scheduledFuture == null || scheduledFuture.isDone())
return false;
return true;
}
}
}