org.eclipse.jetty.util.statistic.CounterStatistic Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2018 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;
import java.util.concurrent.atomic.LongAccumulator;
import java.util.concurrent.atomic.LongAdder;
/**
* Statistics on a counter value.
* This class keeps the total, current and maximum value of a counter
* that can be incremented and decremented. The total refers only to increments.
*/
public class CounterStatistic
{
private final LongAccumulator _max = new LongAccumulator(Math::max, 0L);
private final AtomicLong _current = new AtomicLong();
private final LongAdder _total = new LongAdder();
/**
* Resets the max and total to the current value.
*/
public void reset()
{
_total.reset();
_max.reset();
long current = _current.get();
_total.add(current);
_max.accumulate(current);
}
/**
* Resets the max, total and current value to the given parameter.
*
* @param value the new current value
*/
public void reset(final long value)
{
_current.set(value);
_total.reset();
_max.reset();
if (value > 0)
{
_total.add(value);
_max.accumulate(value);
}
}
/**
* @param delta the amount to add to the counter
* @return the new counter value
*/
public long add(final long delta)
{
long value = _current.addAndGet(delta);
if (delta > 0)
{
_total.add(delta);
_max.accumulate(value);
}
return value;
}
/**
* Increments the value by one.
*
* @return the new counter value after the increment
*/
public long increment()
{
long value = _current.incrementAndGet();
_total.increment();
_max.accumulate(value);
return value;
}
/**
* Decrements the value by one.
*
* @return the new counter value after the decrement
*/
public long decrement()
{
return _current.decrementAndGet();
}
/**
* @return max counter value
*/
public long getMax()
{
return _max.get();
}
/**
* @return current counter value
*/
public long getCurrent()
{
return _current.get();
}
/**
* @return total counter value
*/
public long getTotal()
{
return _total.sum();
}
@Override
public String toString()
{
return String.format("%s@%x{c=%d,m=%d,t=%d}", getClass().getSimpleName(), hashCode(), getCurrent(), getMax(), getTotal());
}
}