/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
/***************************************************************************************
* Attribution Notice
*
* This file is imported from Metrics (https://github.com/codahale/metrics subproject metrics-core).
* Metrics is Copyright (c) 2010-2012 Coda Hale, Yammer.com
* Metrics is Published under Apache Software License 2.0, see LICENSE in root folder.
*
* Thank you for the Metrics developers efforts in making their library available under an Apache license.
* EsperTech incorporates Metrics version 0.2.2 in source code form since Metrics depends on SLF4J
* and this dependency is not possible to introduce for Esper.
* *************************************************************************************
*/
package com.espertech.esper.metrics.codahale_metrics.metrics.core;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
/**
* An abstraction for how time passes. It is passed to {@link Timer} to track timing.
*/
public abstract class Clock {
/**
* Returns the current time tick.
*
* @return time tick in nanoseconds
*/
public abstract long tick();
/**
* Returns the current time in milliseconds.
*
* @return time in milliseconds
*/
public long time() {
return System.currentTimeMillis();
}
private static final Clock DEFAULT = new UserTimeClock();
/**
* The default clock to use.
*
* @return the default {@link Clock} instance
*/
public static Clock defaultClock() {
return DEFAULT;
}
/**
* A clock implementation which returns the current time in epoch nanoseconds.
*/
public static class UserTimeClock extends Clock {
@Override
public long tick() {
return System.nanoTime();
}
}
/**
* A clock implementation which returns the current thread's CPU time.
*/
public static class CpuTimeClock extends Clock {
private static final ThreadMXBean THREAD_MX_BEAN = ManagementFactory.getThreadMXBean();
@Override
public long tick() {
return THREAD_MX_BEAN.getCurrentThreadCpuTime();
}
}
}