org.eclipse.jetty.util.statistic.CounterStatistic Maven / Gradle / Ivy
// ========================================================================
// Copyright (c) 2009-2009 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
package org.eclipse.jetty.util.statistic;
import java.util.concurrent.atomic.AtomicLong;
/* ------------------------------------------------------------ */
/** Statistics on a counter value.
*
* Keep total, current and maximum values of a counter that
* can be incremented and decremented. The total refers only
* to increments.
*
*/
public class CounterStatistic
{
protected final AtomicLong _max = new AtomicLong();
protected final AtomicLong _curr = new AtomicLong();
protected final AtomicLong _total = new AtomicLong();
/* ------------------------------------------------------------ */
public void reset()
{
reset(0);
}
/* ------------------------------------------------------------ */
public void reset(final long value)
{
_max.set(value);
_curr.set(value);
_total.set(0); // total always set to 0 to properly calculate cumulative total
}
/* ------------------------------------------------------------ */
/**
* @param delta the amount to add to the count
*/
public void add(final long delta)
{
long value=_curr.addAndGet(delta);
if (delta > 0)
_total.addAndGet(delta);
long oldValue = _max.get();
while (value > oldValue)
{
if (_max.compareAndSet(oldValue, value))
break;
oldValue = _max.get();
}
}
/* ------------------------------------------------------------ */
/**
* @param delta the amount to subtract the count by.
*/
public void subtract(final long delta)
{
add(-delta);
}
/* ------------------------------------------------------------ */
/**
*/
public void increment()
{
add(1);
}
/* ------------------------------------------------------------ */
/**
*/
public void decrement()
{
add(-1);
}
/* ------------------------------------------------------------ */
/**
* @return max value
*/
public long getMax()
{
return _max.get();
}
/* ------------------------------------------------------------ */
/**
* @return current value
*/
public long getCurrent()
{
return _curr.get();
}
/* ------------------------------------------------------------ */
/**
* @return total value
*/
public long getTotal()
{
return _total.get();
}
/* ------------------------------------------------------------ */
protected void upxdateMax(long value)
{
}
}