Timer.java
/*
* Java Genetic Algorithm Library (@__identifier__@).
* Copyright (c) @__year__@ Franz Wilhelmstötter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Author:
* Franz Wilhelmstötter (franz.wilhelmstoetter@gmx.at)
*/
package org.jenetics.util;
import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
import static org.jenetics.internal.util.object.eq;
import java.io.Serializable;
import javax.measure.Measurable;
import javax.measure.Measure;
import javax.measure.quantity.Duration;
import javax.measure.unit.SI;
import javolution.lang.Reusable;
import org.jenetics.internal.util.HashBuilder;
/**
* Timer for measure the performance of the GA. The timer uses nano second
* precision (by using {@link System#nanoTime()}). This timer is not synchronized.
* It's up to the user to ensure thread safety.
*
* @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
* @since 1.0
* @version 1.0 — <em>$Date: 2014-03-01 $</em>
*/
public final class Timer
implements
Comparable<Timer>,
Reusable,
Serializable,
Cloneable
{
private static final long serialVersionUID = 1L;
private static final String DEFAULT_LABEL = "Timer";
private String _label;
/*private[test]*/ long _start = 0;
/*private[test]*/ long _stop = 0;
/*private[test]*/ long _sum = 0;
private transient Accumulator<? super Long> _accumulator = accumulators.NULL;
/**
* Create a new time with the given label. The label is use in the
* {@link #toString()} method.
*
* @param label the timer label.
* @throws NullPointerException if the {@code label} is {@code null}.
*/
public Timer(final String label) {
_label = requireNonNull(label, "Time label");
}
/**
* Create a new Timer object.
*/
public Timer() {
this(DEFAULT_LABEL);
}
/**
* Set the accumulator for the interim results.
*
* [code]
* final Mean<Long> variance = new Mean<>();
* final Timer timer = new Timer();
* timer.setAccumulator(variance);
*
* for (int i = 0; i < 100; ++I) {
* timer.start();
* ... // Do some measurable task.
* timer.stop();
* }
*
* // Print the average time used for the 'measurable' task.
* System.out.println(mean.getMean());
* [/code]
*
* @param accumulator the accumulator used for the interim results.
* @throws NullPointerException if the {@code accumulator} is {@code null}.
*/
public void setAccumulator(final Accumulator<? super Long> accumulator) {
_accumulator = requireNonNull(accumulator, "Accumulator");
}
/**
* Start the timer.
*/
public void start() {
_start = System.nanoTime();
}
/**
* Stop the timer.
*/
public void stop() {
_stop = System.nanoTime();
final long time = _stop - _start;
_accumulator.accumulate(time);
_sum += time;
}
/**
* Reset the timer.
*/
@Override
public void reset() {
_sum = 0;
_start = 0;
_stop = 0;
}
/**
* Return the overall time of this timer. The following code snippet would
* return a measured time of 10 s (theoretically).
* [code]
* final Timer timer = new Timer();
* for (int i = 0; i < 10; ++i) {
* timer.start();
* Thread.sleep(1000);
* timer.stop();
* }
* [/code]
*
* @return the measured time so far.
*/
public Measurable<Duration> getTime() {
return Measure.valueOf(_sum, SI.NANO(SI.SECOND));
}
/**
* Return the time between two successive calls of {@link #start()} and
* {@link #stop()}.
*
* @return the interim time measured.
*/
public Measurable<Duration> getInterimTime() {
return Measure.valueOf(_stop - _start, SI.NANO(SI.SECOND));
}
/**
* Return the timer label.
*
* @return the timer label.
*/
public String getLabel() {
return _label;
}
/**
* Set the timer label.
*
* @param label the new timer label
*/
public void setLabel(final String label) {
_label = requireNonNull(label, "Timer label");
}
@Override
public int compareTo(final Timer timer) {
requireNonNull(timer, "Timer");
long diff = _sum - timer._sum;
int comp = 0;
if (diff < 0) {
comp = -1;
} else if (diff > 0) {
comp = 1;
}
return comp;
}
@Override
public int hashCode() {
return HashBuilder.of(getClass()).
and(_label).
and(_start).
and(_stop).
and(_sum).value();
}
@Override
public boolean equals(final Object object) {
if (object == this) {
return true;
}
if (!(object instanceof Timer)) {
return false;
}
final Timer timer = (Timer)object;
return eq(_start, timer._start) &&
eq(_stop, timer._stop) &&
eq(_sum, timer._sum) &&
eq(_label, timer._label);
}
@Override
public Timer clone() {
try {
return (Timer)super.clone();
} catch (CloneNotSupportedException e) {
throw new AssertionError(e);
}
}
@Override
public String toString() {
return format(
"%s: %11.11f s", _label,
getTime().doubleValue(SI.SECOND)
);
}
}