Java Tutorial/Development/Stop Watch
Содержание
Provides the programatic analog of a physical stop watch
<source lang="java">
/* Copyright (c) 2001-2009, The HSQL Development Group
* All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the HSQL Development Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/**
* Provides the programatic analog of a physical stop watch. * * The watch can be started, stopped and zeroed and can be queried for * elapsed running time. The watch accumulates elapsed time over starts * and stops such that only the time actually spent running is recorded. * If the watch is zeroed, then the accumulated time is discarded and * the watch starts again with zero acumulated time. * * @author boucherb@users * @version 1.7.2 * @since 1.7.2 */
public class StopWatch {
/**
* The last time this object made the transition
* from stopped to running state, as reported
* by System.currentTimeMillis().
*/
private long startTime;
private long lastStart;
/**
* The accumulated running time of this object since
* it was last zeroed.
*/
private long total;
/** Flags if this object is started or stopped. */
boolean running = false;
/** Creates, zeros, and starts a new StopWatch */
public StopWatch() {
this(true);
}
/** Creates, zeros, and starts a new StopWatch */
public StopWatch(boolean start) {
if (start) {
start();
}
}
/**
* Retrieves the accumulated time this object has spent running since
* it was last zeroed.
* @return the accumulated time this object has spent running since
* it was last zeroed.
*/
public long elapsedTime() {
if (running) {
return total + System.currentTimeMillis() - startTime;
} else {
return total;
}
}
/**
* Retrieves the accumulated time this object has spent running since
* it was last started.
* @return the accumulated time this object has spent running since
* it was last started.
*/
public long currentElapsedTime() {
if (running) {
return System.currentTimeMillis() - startTime;
} else {
return 0;
}
}
/** Zeros accumulated running time and restarts this object. */
public void zero() {
total = 0;
start();
}
/**
* Ensures that this object is in the running state. If this object is not
* running, then the call has the effect of setting the startTime
* attribute to the current value of System.currentTimeMillis() and setting
* the running attribute to true.
*/
public void start() {
startTime = System.currentTimeMillis();
running = true;
}
/**
* Ensures that this object is in the stopped state. If this object is
* in the running state, then this has the effect of adding to the
* total attribute the elapsed time since the last transition
* from stopped to running state and sets the running attribute
* to false. If this object is not in the running state, this call has no
* effect.
*/
public void stop() {
if (running) {
total += System.currentTimeMillis() - startTime;
running = false;
}
}
public void mark() {
stop();
start();
}
/**
* Retrieves prefix + " in " + elapsedTime() + " ms."
* @param prefix The string to use as a prefix
* @return prefix + " in " + elapsedTime() + " ms."
*/
public String elapsedTimeToMessage(String prefix) {
return prefix + " in " + elapsedTime() + " ms.";
}
/**
* Retrieves prefix + " in " + elapsedTime() + " ms."
* @param prefix The string to use as a prefix
* @return prefix + " in " + elapsedTime() + " ms."
*/
public String currentElapsedTimeToMessage(String prefix) {
return prefix + " in " + currentElapsedTime() + " ms.";
}
/**
* Retrieves the internal state of this object, as a String.
*
* The retreived value is:
*
*
* super.toString() +
* "[running=" +
* running +
* ", startTime=" +
* startTime +
* ", total=" +
* total + "]";
*
* @return the state of this object, as a String
*/
public String toString() {
return super.toString() + "[running=" + running + ", startTime="
+ startTime + ", total=" + total + "]";
}
}</source>
Simple stop watch
<source lang="java">
/*
* Copyright 2002-2007 the original author or authors. * * 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. */
import java.text.NumberFormat; import java.util.LinkedList; import java.util.List; /**
* Simple stop watch, allowing for timing of a number of tasks,
* exposing total running time and running time for each named task.
*
* Conceals use of System.currentTimeMillis(), improving the
* readability of application code and reducing the likelihood of calculation errors.
*
* Note that this object is not designed to be thread-safe and does not
* use synchronization.
*
* This class is normally used to verify performance during proof-of-concepts
* and in development, rather than as part of production applications.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since May 2, 2001
*/
public class StopWatch {
/** * Identifier of this stop watch. * Handy when we have output from multiple stop watches * and need to distinguish between them in log or console output. */ private final String id; private boolean keepTaskList = true; /** List of TaskInfo objects */ private final List taskList = new LinkedList(); /** Start time of the current task */ private long startTimeMillis; /** Is the stop watch currently running? */ private boolean running; /** Name of the current task */ private String currentTaskName; private TaskInfo lastTaskInfo; private int taskCount; /** Total running time */ private long totalTimeMillis;
/**
* Construct a new stop watch. Does not start any task.
*/
public StopWatch() {
this.id = "";
}
/**
* Construct a new stop watch with the given id.
* Does not start any task.
* @param id identifier for this stop watch.
* Handy when we have output from multiple stop watches
* and need to distinguish between them.
*/
public StopWatch(String id) {
this.id = id;
}
/**
* Determine whether the TaskInfo array is built over time. Set this to
* "false" when using a StopWatch for millions of intervals, or the task
* info structure will consume excessive memory. Default is "true".
*/
public void setKeepTaskList(boolean keepTaskList) {
this.keepTaskList = keepTaskList;
}
/**
* Start an unnamed task. The results are undefined if {@link #stop()}
* or timing methods are called without invoking this method.
* @see #stop()
*/
public void start() throws IllegalStateException {
start("");
}
/**
* Start a named task. The results are undefined if {@link #stop()}
* or timing methods are called without invoking this method.
* @param taskName the name of the task to start
* @see #stop()
*/
public void start(String taskName) throws IllegalStateException {
if (this.running) {
throw new IllegalStateException("Can"t start StopWatch: it"s already running");
}
this.startTimeMillis = System.currentTimeMillis();
this.running = true;
this.currentTaskName = taskName;
}
/**
* Stop the current task. The results are undefined if timing
* methods are called without invoking at least one pair
* {@link #start()} / {@link #stop()} methods.
* @see #start()
*/
public void stop() throws IllegalStateException {
if (!this.running) {
throw new IllegalStateException("Can"t stop StopWatch: it"s not running");
}
long lastTime = System.currentTimeMillis() - this.startTimeMillis;
this.totalTimeMillis += lastTime;
this.lastTaskInfo = new TaskInfo(this.currentTaskName, lastTime);
if (this.keepTaskList) {
this.taskList.add(lastTaskInfo);
}
++this.taskCount;
this.running = false;
this.currentTaskName = null;
}
/**
* Return whether the stop watch is currently running.
*/
public boolean isRunning() {
return this.running;
}
/**
* Return the time taken by the last task.
*/
public long getLastTaskTimeMillis() throws IllegalStateException {
if (this.lastTaskInfo == null) {
throw new IllegalStateException("No tests run: can"t get last interval");
}
return this.lastTaskInfo.getTimeMillis();
}
/**
* Return the total time in milliseconds for all tasks.
*/
public long getTotalTimeMillis() {
return totalTimeMillis;
}
/**
* Return the total time in seconds for all tasks.
*/
public double getTotalTimeSeconds() {
return totalTimeMillis / 1000.0;
}
/**
* Return the number of tasks timed.
*/
public int getTaskCount() {
return taskCount;
}
/**
* Return an array of the data for tasks performed.
*/
public TaskInfo[] getTaskInfo() {
if (!this.keepTaskList) {
throw new UnsupportedOperationException("Task info is not being kept!");
}
return (TaskInfo[]) this.taskList.toArray(new TaskInfo[this.taskList.size()]);
}
/**
* Return a short description of the total running time.
*/
public String shortSummary() {
return "StopWatch "" + this.id + "": running time (millis) = " + getTotalTimeMillis();
}
/**
* Return a string with a table describing all tasks performed.
* For custom reporting, call getTaskInfo() and use the task info directly.
*/
public String prettyPrint() {
StringBuffer sb = new StringBuffer(shortSummary());
sb.append("\n");
if (!this.keepTaskList) {
sb.append("No task info kept");
}
else {
TaskInfo[] tasks = getTaskInfo();
sb.append("-----------------------------------------\n");
sb.append("ms % Task name\n");
sb.append("-----------------------------------------\n");
NumberFormat nf = NumberFormat.getNumberInstance();
nf.setMinimumIntegerDigits(5);
nf.setGroupingUsed(false);
NumberFormat pf = NumberFormat.getPercentInstance();
pf.setMinimumIntegerDigits(3);
pf.setGroupingUsed(false);
for (int i = 0; i < tasks.length; i++) {
sb.append(nf.format(tasks[i].getTimeMillis()) + " ");
sb.append(pf.format(tasks[i].getTimeSeconds() / getTotalTimeSeconds()) + " ");
sb.append(tasks[i].getTaskName() + "\n");
}
}
return sb.toString();
}
/**
* Return an informative string describing all tasks performed
* For custom reporting, call getTaskInfo() and use the task info directly.
*/
public String toString() {
StringBuffer sb = new StringBuffer(shortSummary());
if (this.keepTaskList) {
TaskInfo[] tasks = getTaskInfo();
for (int i = 0; i < tasks.length; i++) {
sb.append("; [" + tasks[i].getTaskName() + "] took " + tasks[i].getTimeMillis());
long percent = Math.round((100.0 * tasks[i].getTimeSeconds()) / getTotalTimeSeconds());
sb.append(" = " + percent + "%");
}
}
else {
sb.append("; no task info kept");
}
return sb.toString();
}
/**
* Inner class to hold data about one task executed within the stop watch.
*/
public static class TaskInfo {
private final String taskName;
private final long timeMillis;
private TaskInfo(String taskName, long timeMillis) {
this.taskName = taskName;
this.timeMillis = timeMillis;
}
/**
* Return the name of this task.
*/
public String getTaskName() {
return taskName;
}
/**
* Return the time in milliseconds this task took.
*/
public long getTimeMillis() {
return timeMillis;
}
/**
* Return the time in seconds this task took.
*/
public double getTimeSeconds() {
return timeMillis / 1000.0;
}
}
}</source>
Some simple stop watch.
<source lang="java">
/*
* Copyright 2000,2005 wingS development team. * * This file is part of wingS (http://wingsframework.org). * * wingS is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation; either version 2.1 * of the License, or (at your option) any later version. * * Please see COPYING for the complete licence. */
import java.text.MessageFormat; import java.util.ArrayList; import java.util.Iterator; /*
* Ein Klasse, die Zeitmessungen aufnimmt und diese in Relation zueineander * setzt. Zum Start der Zeitmessung Methode start kurzer Beschreibung was * gemessen wird als Parameter aufrufen. Das Ende der Zeitmessung wird durch * stop angezeigt. Es kann nur eine Zeitmessung gleichzeitig stattfinden. Die * Ausgabe ist nicht sortiert, gibt aber die relativen Unterschiede in der * Dauer der einzelnen Messungen an. Die Messung mit der laengsten Dauer ist * der Referenzwert (1.0). */
/**
* Some simple stop watch. It allows to measure multiple time periods * and prints them. Usage: call start(comment) and stop() for * each period of time. * * @author */
public class TimeMeasure {
protected final static double RESOLUTION = 100.0;
/**
* List of measurements.
*/
protected final ArrayList measures;
/**
* Message formatter
*/
protected final MessageFormat formatter;
/**
* the current time measurement.
*/
protected Measure current;
/**
* Simple TimeMesaure with default format.
*/
public TimeMeasure() {
this(new MessageFormat("{0}\t: {1}\t {2}x\n"));
}
/**
* A new TimeMeasure which reports in a specific format. The
* format is a standard MessageFormat with the following variables:
* -
*
{0}the measurement comment
* {1}the time it took
* {2}how many times this is faster than the * slowest measurement
*
*/
public TimeMeasure(MessageFormat formatter) {
this.measures = new ArrayList();
this.formatter = formatter;
}
/**
* Reset of all Measurements.
*/
public void reset() {
measures.clear();
}
/*
* Startet eine neue Messsung.
* @param comment Die Beschreibung der Messung.
*/
public void start(String comment) {
current = new Measure(comment);
}
/*
* Startet eine neue Messsung.
* @param comment Die Beschreibung der Messung.
public Object generate(String comment) {
current = new Measure();
actual.rument = comment;
measures.add(actual);
return actual;
}
*/
/*
* Addiert eine Messsung zu einer bestehenden.
* @param comment Die Beschreibung der Messung.
public void addToMeasure(Object measure) {
int index = measures.indexOf(measure);
if ( index<0 ) {
System.err.println("Measure does not exists " + measure);
actual = null;
return;
}
actual = (Measure)measures.get(index);
measures.remove(index);
actual.start = System.currentTimeMillis();
}
*/
/**
* stop current time measurement and store it.
*/
public void stop() {
if (current != null) {
current.stop();
measures.add(current);
current = null;
}
}
/**
* determines the time duration of the longest or shortest time interval.
*
* @param findShortest boolean "true", if we are looking for the shortest
* time interval; "false" if we are looking for the
* longest.
*/
private long findReferenceValue(boolean findShortest) {
long result = findShortest ? Long.MAX_VALUE : -1;
Iterator it = measures.iterator();
while (it.hasNext()) {
Measure m = (Measure) it.next();
result = (findShortest
? Math.min(result, m.getDuration())
: Math.max(result, m.getDuration()));
}
return result;
}
public String print() {
return print(false);
}
/**
* creates a formatted output (using the MessageFormat) of all
* results. The output is sorted in the in the sequence the time
* measurements took place.
* Writes the relative time to either the shortest or the longest
* time interval.
*
* @param shortestIsReference boolean true, if the shortest time interval
* is the reference value (1.0). False, if the
* longest is the reference.
*/
public String print(boolean shortestIsReference) {
StringBuilder result = new StringBuilder();
long reference = findReferenceValue(shortestIsReference);
Iterator it = measures.iterator();
while (it.hasNext()) {
Measure m = (Measure) it.next();
String factor = " -- ";
long duration = m.getDuration();
if (reference > 0) {
long tmp = (long) ((duration * RESOLUTION) / reference);
factor = String.valueOf(tmp / RESOLUTION);
}
Object[] args = {m.getComment(), (duration + "ms"), factor};
result.append(formatter.format(args));
}
return result.toString();
}
public String toString() {
return print();
}
/**
* A class to store one period of time.
*/
private final static class Measure {
/**
* start time.
*/
private final long start;
/**
* stop time.
*/
private long stop;
/**
* Die Gesamtdauer der Messung
*/
private long duration;
/**
* Description.
*/
private String comment;
public Measure(String comment) {
start = System.currentTimeMillis();
this.rument = comment;
}
public void stop() {
stop = System.currentTimeMillis();
duration = stop - start;
}
public long getDuration() { return duration; }
public String getComment() { return comment; }
}
}</source>
Stop Watch
<source lang="java">
import java.io.PrintWriter; /**
* Prints time durations; used for development purposes only.
*
* No threads or system resources are harmed in the making of a stop watch. A
* stop watch simply remembers the start time (and elapsed time when paused) and
* prints the total "running" time when either {@link #mark} or
* {@link #stop} is called.
*
* {@link #stop} doesn"t really stop anything. You can call stop as many times
* as you like and it will print the time elapsed since start. It would be easy
* to change this behavior, but I haven"t needed to.
*
* @author Jim Menard,
*/
public class StopWatch {
protected String name;
protected long t0;
protected long elapsedTime;
protected PrintWriter out;
public StopWatch() {
this(null, null);
}
public StopWatch(String name) {
this(name, null);
}
public StopWatch(PrintWriter out) {
this(null, out);
}
public StopWatch(String name, PrintWriter out) {
this.name = name;
if (out == null)
this.out = new PrintWriter(System.err);
else
this.out = out;
elapsedTime = -1L; // So we can tell if we are ever started
}
/**
* Remembers the current time and prints a message.
*/
public void start() {
start(true);
}
/**
* Remembers the current time and prints a message if requested.
*
* @param printStarting
* if true and this stop watch has a name, print a
* message
*/
public void start(boolean printStarting) {
if (t0 != 0)
System.err.println("(warning: StopWatch already started; resetting)");
if (printStarting && name != null)
System.err.println("starting " + name);
elapsedTime = 0;
t0 = System.currentTimeMillis();
}
/**
* Pauses the stop watch.
*/
public void pause() {
long now = System.currentTimeMillis();
elapsedTime += now - t0;
t0 = 0;
}
/**
* Resumes the stop watch.
*/
public void resume() {
t0 = System.currentTimeMillis();
}
/**
* Prints the current elapsed time without stopping.
*/
public void mark() {
stop(null, true);
}
/**
* Prints the current elapsed time without stopping, along with the stop watch
* name if printMark is true.
*
* @param printMark
* if true, the stop watch name will be printed
*/
public void mark(boolean printMark) {
stop(null, printMark);
}
/**
* Prints the current elapsed time without stopping, along with the stop watch
* name and msg.
*
* @param msg
* a message to print
*/
public void mark(String msg) {
stop(msg, true);
}
/**
* Prints the current elapsed time without stopping, along with, along with
* the stop watch name if printMark is true and the
* msg if it"s not null.
*
* @param msg
* a message to print
* @param printMark
* if true, the stop watch name will be printed
*/
public void mark(String msg, boolean printMark) {
stop(msg, printMark);
}
/**
* Stops the stop watch and prints the name of this stop watch and the current
* elapsed time.
*/
public void stop() {
stop(null, true);
}
/**
* Stops the stop watch and prints the name of this stop watch, msg
* if non-null, and the current elapsed time.
*
* @param msg
* a message to print; may be null
*/
public void stop(String msg) {
stop(msg, true);
}
/**
* Prints the current elapsed time, along with the stop watch name if
* printMark is true and the msg if
* it"s not null.
*
* @param msg
* a message to print; may be null
* @param printName
* if true, the stop watch name will be printed
*/
public void stop(String msg, boolean printName) {
long now = System.currentTimeMillis();
if (elapsedTime == -1) {
System.err.println("(StopWatch" + (name != null ? (" \"" + name + """) : "")
+ " was stopped without ever being started)");
return;
}
long total = elapsedTime;
if (t0 != 0)
total += now - t0;
String separator = null;
if (printName && name != null) {
System.err.print(name);
separator = ": ";
}
if (msg != null) {
if (separator != null)
System.err.print(" ");
System.err.print("(" + msg + ")");
separator = ": ";
}
if (separator != null)
System.err.print(separator);
System.err.println("" + (total / 1000.0) + " seconds");
}
}</source>
StopWatch provides a convenient API for timings.
<source lang="java">
import java.util.Date; /*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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. */
/**
*
* StopWatch provides a convenient API for timings.
*
*
*
* To start the watch, call {@link #start()}. At this point you can:
*
* -
*
- {@link #split()} the watch to get the time whilst the watch continues in the background. {@link #unsplit()} will * remove the effect of the split. At this point, these three options are available again. *
- {@link #suspend()} the watch to pause it. {@link #resume()} allows the watch to continue. Any time between the * suspend and resume will not be counted in the total. At this point, these three options are available again. *
- {@link #stop()} the watch to complete the timing session. *
*
*
* It is intended that the output methods {@link #toString()} and {@link #getTime()} should only be called after stop,
* split or suspend, however a suitable result will be returned at other points.
*
*
*
* NOTE: As from v2.1, the methods protect against inappropriate calls. Thus you cannot now call stop before start,
* resume before suspend or unsplit before split.
*
*
*
* 1. split(), suspend(), or stop() cannot be invoked twice
* 2. unsplit() may only be called if the watch has been split()
* 3. resume() may only be called if the watch has been suspend()
* 4. start() cannot be called twice without calling reset()
*
*
* @author Stephen Colebourne
* @since 2.0
* @version $Id: StopWatch.java 583608 2007-10-10 20:38:41Z ggregory $
*/
public class StopWatch {
// running states
private static final int STATE_UNSTARTED = 0;
private static final int STATE_RUNNING = 1;
private static final int STATE_STOPPED = 2;
private static final int STATE_SUSPENDED = 3;
// split state
private static final int STATE_UNSPLIT = 10;
private static final int STATE_SPLIT = 11;
/**
* The current running state of the StopWatch.
*/
private int runningState = STATE_UNSTARTED;
/**
* Whether the stopwatch has a split time recorded.
*/
private int splitState = STATE_UNSPLIT;
/**
* The start time.
*/
private long startTime = -1;
/**
* The stop time.
*/
private long stopTime = -1;
/**
*
* Constructor.
*
*/
public StopWatch() {
super();
}
/**
*
* Start the stopwatch.
*
*
*
* This method starts a new timing session, clearing any previous values.
*
*
* @throws IllegalStateException
* if the StopWatch is already running.
*/
public void start() {
if (this.runningState == STATE_STOPPED) {
throw new IllegalStateException("Stopwatch must be reset before being restarted. ");
}
if (this.runningState != STATE_UNSTARTED) {
throw new IllegalStateException("Stopwatch already started. ");
}
this.stopTime = -1;
this.startTime = System.currentTimeMillis();
this.runningState = STATE_RUNNING;
}
/**
*
* Stop the stopwatch.
*
*
*
* This method ends a new timing session, allowing the time to be retrieved.
*
*
* @throws IllegalStateException
* if the StopWatch is not running.
*/
public void stop() {
if (this.runningState != STATE_RUNNING && this.runningState != STATE_SUSPENDED) {
throw new IllegalStateException("Stopwatch is not running. ");
}
if (this.runningState == STATE_RUNNING) {
this.stopTime = System.currentTimeMillis();
}
this.runningState = STATE_STOPPED;
}
/**
*
* Resets the stopwatch. Stops it if need be.
*
*
*
* This method clears the internal values to allow the object to be reused.
*
*/
public void reset() {
this.runningState = STATE_UNSTARTED;
this.splitState = STATE_UNSPLIT;
this.startTime = -1;
this.stopTime = -1;
}
/**
*
* Split the time.
*
*
*
* This method sets the stop time of the watch to allow a time to be extracted. The start time is unaffected,
* enabling {@link #unsplit()} to continue the timing from the original start point.
*
*
* @throws IllegalStateException
* if the StopWatch is not running.
*/
public void split() {
if (this.runningState != STATE_RUNNING) {
throw new IllegalStateException("Stopwatch is not running. ");
}
this.stopTime = System.currentTimeMillis();
this.splitState = STATE_SPLIT;
}
/**
*
* Remove a split.
*
*
*
* This method clears the stop time. The start time is unaffected, enabling timing from the original start point to
* continue.
*
*
* @throws IllegalStateException
* if the StopWatch has not been split.
*/
public void unsplit() {
if (this.splitState != STATE_SPLIT) {
throw new IllegalStateException("Stopwatch has not been split. ");
}
this.stopTime = -1;
this.splitState = STATE_UNSPLIT;
}
/**
*
* Suspend the stopwatch for later resumption.
*
*
*
* This method suspends the watch until it is resumed. The watch will not include time between the suspend and
* resume calls in the total time.
*
*
* @throws IllegalStateException
* if the StopWatch is not currently running.
*/
public void suspend() {
if (this.runningState != STATE_RUNNING) {
throw new IllegalStateException("Stopwatch must be running to suspend. ");
}
this.stopTime = System.currentTimeMillis();
this.runningState = STATE_SUSPENDED;
}
/**
*
* Resume the stopwatch after a suspend.
*
*
*
* This method resumes the watch after it was suspended. The watch will not include time between the suspend and
* resume calls in the total time.
*
*
* @throws IllegalStateException
* if the StopWatch has not been suspended.
*/
public void resume() {
if (this.runningState != STATE_SUSPENDED) {
throw new IllegalStateException("Stopwatch must be suspended to resume. ");
}
this.startTime += (System.currentTimeMillis() - this.stopTime);
this.stopTime = -1;
this.runningState = STATE_RUNNING;
}
/**
*
* Get the time on the stopwatch.
*
*
*
* This is either the time between the start and the moment this method is called, or the amount of time between
* start and stop.
*
*
* @return the time in milliseconds
*/
public long getTime() {
if (this.runningState == STATE_STOPPED || this.runningState == STATE_SUSPENDED) {
return this.stopTime - this.startTime;
} else if (this.runningState == STATE_UNSTARTED) {
return 0;
} else if (this.runningState == STATE_RUNNING) {
return System.currentTimeMillis() - this.startTime;
}
throw new RuntimeException("Illegal running state has occured. ");
}
/**
*
* Get the split time on the stopwatch.
*
*
*
* This is the time between start and latest split.
*
*
* @return the split time in milliseconds
*
* @throws IllegalStateException
* if the StopWatch has not yet been split.
* @since 2.1
*/
public long getSplitTime() {
if (this.splitState != STATE_SPLIT) {
throw new IllegalStateException("Stopwatch must be split to get the split time. ");
}
return this.stopTime - this.startTime;
}
/**
* Returns the time this stopwatch was started.
*
* @return the time this stopwatch was started
* @throws IllegalStateException
* if this StopWatch has not been started
* @since 2.4
*/
public long getStartTime() {
if (this.runningState == STATE_UNSTARTED) {
throw new IllegalStateException("Stopwatch has not been started");
}
return this.startTime;
}
/**
*
* Gets a summary of the time that the stopwatch recorded as a string.
*
*
*
* The format used is ISO8601-like, hours:minutes:seconds.milliseconds.
*
*
* @return the time as a String
*/
public String toString() {
return new Date(getTime()).toString();
}
/**
*
* Gets a summary of the split time that the stopwatch recorded as a string.
*
*
*
* The format used is ISO8601-like, hours:minutes:seconds.milliseconds.
*
*
* @return the split time as a String
* @since 2.1
*/
public String toSplitString() {
return new Date(getSplitTime()).toString();
}
}</source>
