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Neo4j kernel is a lightweight, embedded Java database designed to
store data structured as graphs rather than tables. For more
information, see http://neo4j.org.
/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j 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, either version 3 of the License, or
* (at your option) any later version.
*
* 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, see .
*/
package org.neo4j.kernel.impl.cache;
import org.neo4j.logging.Log;
public class MeasureDoNothing extends Thread
{
private volatile boolean measure = true;
private final long TIME_TO_WAIT;
private final long NOTIFICATION_THRESHOLD;
private final Log log;
public MeasureDoNothing( String threadName, Log log, long timeToWait, long pauseNotificationThreshold )
{
super( threadName );
if ( log == null )
{
throw new IllegalArgumentException( "Null message log" );
}
this.log = log;
this.TIME_TO_WAIT = timeToWait;
this.NOTIFICATION_THRESHOLD = pauseNotificationThreshold + timeToWait;
setDaemon( true );
}
@Override
public synchronized void run()
{
log.debug( "GC Monitor started. " );
while ( measure )
{
long start = System.nanoTime();
try
{
this.wait( TIME_TO_WAIT );
}
catch ( InterruptedException e )
{
Thread.interrupted();
}
long time = (System.nanoTime() - start) / 1_000_000;
if ( time > NOTIFICATION_THRESHOLD )
{
long blockTime = time - TIME_TO_WAIT;
log.warn( String.format( "GC Monitor: Application threads blocked for %dms.", blockTime ) );
}
}
log.debug( "GC Monitor stopped. " );
}
public synchronized void stopMeasuring()
{
measure = false;
this.interrupt();
}
}