001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.lang3.time;
019
020import java.util.Objects;
021import java.util.concurrent.TimeUnit;
022
023import org.apache.commons.lang3.StringUtils;
024
025/**
026 * {@link StopWatch} provides a convenient API for timings.
027 *
028 * <p>
029 * To start the watch, call {@link #start()} or {@link StopWatch#createStarted()}. At this point you can:
030 * </p>
031 * <ul>
032 * <li>{@link #split()} the watch to get the time whilst the watch continues in the background. {@link #unsplit()} will
033 * remove the effect of the split. At this point, these three options are available again.</li>
034 * <li>{@link #suspend()} the watch to pause it. {@link #resume()} allows the watch to continue. Any time between the
035 * suspend and resume will not be counted in the total. At this point, these three options are available again.</li>
036 * <li>{@link #stop()} the watch to complete the timing session.</li>
037 * </ul>
038 *
039 * <p>
040 * It is intended that the output methods {@link #toString()} and {@link #getTime()} should only be called after stop,
041 * split or suspend, however a suitable result will be returned at other points.
042 * </p>
043 *
044 * <p>
045 * NOTE: As from v2.1, the methods protect against inappropriate calls. Thus you cannot now call stop before start,
046 * resume before suspend or unsplit before split.
047 * </p>
048 *
049 * <p>
050 * 1. split(), suspend(), or stop() cannot be invoked twice<br>
051 * 2. unsplit() may only be called if the watch has been split()<br>
052 * 3. resume() may only be called if the watch has been suspend()<br>
053 * 4. start() cannot be called twice without calling reset()
054 * </p>
055 *
056 * <p>This class is not thread-safe</p>
057 *
058 * @since 2.0
059 */
060public class StopWatch {
061
062    /**
063     * Enumeration type which indicates the split status of stopwatch.
064     */
065    private enum SplitState {
066        SPLIT,
067        UNSPLIT
068    }
069
070    /**
071     * Enumeration type which indicates the status of stopwatch.
072     */
073    private enum State {
074
075        RUNNING {
076            @Override
077            boolean isStarted() {
078                return true;
079            }
080            @Override
081            boolean isStopped() {
082                return false;
083            }
084            @Override
085            boolean isSuspended() {
086                return false;
087            }
088        },
089        STOPPED {
090            @Override
091            boolean isStarted() {
092                return false;
093            }
094            @Override
095            boolean isStopped() {
096                return true;
097            }
098            @Override
099            boolean isSuspended() {
100                return false;
101            }
102        },
103        SUSPENDED {
104            @Override
105            boolean isStarted() {
106                return true;
107            }
108            @Override
109            boolean isStopped() {
110                return false;
111            }
112            @Override
113            boolean isSuspended() {
114                return true;
115            }
116        },
117        UNSTARTED {
118            @Override
119            boolean isStarted() {
120                return false;
121            }
122            @Override
123            boolean isStopped() {
124                return true;
125            }
126            @Override
127            boolean isSuspended() {
128                return false;
129            }
130        };
131
132        /**
133         * Returns whether the StopWatch is started. A suspended StopWatch is also started watch.
134         *
135         * @return boolean If the StopWatch is started.
136         */
137        abstract boolean isStarted();
138
139        /**
140         * Returns whether the StopWatch is stopped. The stopwatch which's not yet started and explicitly stopped stopwatch is
141         * considered as stopped.
142         *
143         * @return boolean If the StopWatch is stopped.
144         */
145        abstract boolean isStopped();
146
147        /**
148         * Returns whether the StopWatch is suspended.
149         *
150         * @return boolean
151         *             If the StopWatch is suspended.
152         */
153        abstract boolean isSuspended();
154    }
155
156    private static final long NANO_2_MILLIS = 1000000L;
157
158    /**
159     * Creates a stopwatch for convenience.
160     *
161     * @return StopWatch a stopwatch.
162     *
163     * @since 3.10
164     */
165    public static StopWatch create() {
166        return new StopWatch();
167    }
168
169    /**
170     * Creates a started stopwatch for convenience.
171     *
172     * @return StopWatch a stopwatch that's already been started.
173     *
174     * @since 3.5
175     */
176    public static StopWatch createStarted() {
177        final StopWatch sw = new StopWatch();
178        sw.start();
179        return sw;
180    }
181
182    /**
183     * A message for string presentation.
184     *
185     * @since 3.10
186     */
187    private final String message;
188
189    /**
190     * The current running state of the StopWatch.
191     */
192    private State runningState = State.UNSTARTED;
193
194    /**
195     * Whether the stopwatch has a split time recorded.
196     */
197    private SplitState splitState = SplitState.UNSPLIT;
198
199    /**
200     * The start time in nanoseconds.
201     */
202    private long startTimeNanos;
203
204    /**
205     * The start time in milliseconds - nanoTime is only for elapsed time so we
206     * need to also store the currentTimeMillis to maintain the old
207     * getStartTime API.
208     */
209    private long startTimeMillis;
210
211    /**
212     * The end time in milliseconds - nanoTime is only for elapsed time so we
213     * need to also store the currentTimeMillis to maintain the old
214     * getStartTime API.
215     */
216    private long stopTimeMillis;
217
218    /**
219     * The stop time in nanoseconds.
220     */
221    private long stopTimeNanos;
222
223    /**
224     * Constructor.
225     *
226     */
227    public StopWatch() {
228        this(null);
229    }
230
231    /**
232     * Constructor.
233     *
234     * @param message A message for string presentation.
235     * @since 3.10
236     */
237    public StopWatch(final String message) {
238        this.message = message;
239    }
240
241    /**
242     * Returns the split time formatted by {@link DurationFormatUtils#formatDurationHMS}.
243     *
244     * @return the split time formatted by {@link DurationFormatUtils#formatDurationHMS}.
245     * @since 3.10
246     */
247    public String formatSplitTime() {
248        return DurationFormatUtils.formatDurationHMS(getSplitTime());
249    }
250
251    /**
252     * Returns the time formatted by {@link DurationFormatUtils#formatDurationHMS}.
253     *
254     * @return the time formatted by {@link DurationFormatUtils#formatDurationHMS}.
255     * @since 3.10
256     */
257    public String formatTime() {
258        return DurationFormatUtils.formatDurationHMS(getTime());
259    }
260
261    /**
262     * Gets the message for string presentation.
263     *
264     * @return the message for string presentation.
265     * @since 3.10
266     */
267    public String getMessage() {
268        return message;
269    }
270
271    /**
272     * Gets the <em>elapsed</em> time in nanoseconds.
273     *
274     * <p>
275     * This is either the time between the start and the moment this method is called, or the amount of time between
276     * start and stop.
277     * </p>
278     *
279     * @return the <em>elapsed</em> time in nanoseconds.
280     * @see System#nanoTime()
281     * @since 3.0
282     */
283    public long getNanoTime() {
284        if (this.runningState == State.STOPPED || this.runningState == State.SUSPENDED) {
285            return this.stopTimeNanos - this.startTimeNanos;
286        }
287        if (this.runningState == State.UNSTARTED) {
288            return 0;
289        }
290        if (this.runningState == State.RUNNING) {
291            return System.nanoTime() - this.startTimeNanos;
292        }
293        throw new IllegalStateException("Illegal running state has occurred.");
294    }
295
296    /**
297     * Gets the split time in nanoseconds.
298     *
299     * <p>
300     * This is the time between start and latest split.
301     * </p>
302     *
303     * @return the split time in nanoseconds
304     *
305     * @throws IllegalStateException
306     *             if the StopWatch has not yet been split.
307     * @since 3.0
308     */
309    public long getSplitNanoTime() {
310        if (this.splitState != SplitState.SPLIT) {
311            throw new IllegalStateException("Stopwatch must be split to get the split time.");
312        }
313        return this.stopTimeNanos - this.startTimeNanos;
314    }
315
316    /**
317     * Gets the split time on the stopwatch.
318     *
319     * <p>
320     * This is the time between start and latest split.
321     * </p>
322     *
323     * @return the split time in milliseconds
324     *
325     * @throws IllegalStateException
326     *             if the StopWatch has not yet been split.
327     * @since 2.1
328     */
329    public long getSplitTime() {
330        return getSplitNanoTime() / NANO_2_MILLIS;
331    }
332
333    /**
334     * Gets the time this stopwatch was started in milliseconds, between the current time and midnight, January 1, 1970
335     * UTC.
336     *
337     * @return the time this stopwatch was started in milliseconds, between the current time and midnight, January 1,
338     *         1970 UTC.
339     * @throws IllegalStateException if this StopWatch has not been started
340     * @since 2.4
341     */
342    public long getStartTime() {
343        if (this.runningState == State.UNSTARTED) {
344            throw new IllegalStateException("Stopwatch has not been started");
345        }
346        // System.nanoTime is for elapsed time
347        return this.startTimeMillis;
348    }
349
350    /**
351     * Gets the time this stopwatch was stopped in milliseconds, between the current time and midnight, January 1, 1970
352     * UTC.
353     *
354     * @return the time this stopwatch was started in milliseconds, between the current time and midnight, January 1,
355     *         1970 UTC.
356     * @throws IllegalStateException if this StopWatch has not been started
357     * @since 3.12.0
358     */
359    public long getStopTime() {
360        if (this.runningState == State.UNSTARTED) {
361            throw new IllegalStateException("Stopwatch has not been started");
362        }
363        // System.nanoTime is for elapsed time
364        return this.stopTimeMillis;
365    }
366
367    /**
368     * Gets the time on the stopwatch.
369     *
370     * <p>
371     * This is either the time between the start and the moment this method is called, or the amount of time between
372     * start and stop.
373     * </p>
374     *
375     * @return the time in milliseconds
376     */
377    public long getTime() {
378        return getNanoTime() / NANO_2_MILLIS;
379    }
380
381    /**
382     * Gets the time in the specified TimeUnit.
383     *
384     * <p>
385     * This is either the time between the start and the moment this method is called, or the amount of time between
386     * start and stop. The resulting time will be expressed in the desired TimeUnit with any remainder rounded down.
387     * For example, if the specified unit is {@code TimeUnit.HOURS} and the stopwatch time is 59 minutes, then the
388     * result returned will be {@code 0}.
389     * </p>
390     *
391     * @param timeUnit the unit of time, not null
392     * @return the time in the specified TimeUnit, rounded down
393     * @since 3.5
394     */
395    public long getTime(final TimeUnit timeUnit) {
396        return timeUnit.convert(getNanoTime(), TimeUnit.NANOSECONDS);
397    }
398
399    /**
400     * Returns whether the StopWatch is started. A suspended StopWatch is also started watch.
401     *
402     * @return boolean If the StopWatch is started.
403     * @since 3.2
404     */
405    public boolean isStarted() {
406        return runningState.isStarted();
407    }
408
409    /**
410     * Returns whether StopWatch is stopped. The stopwatch which's not yet started and explicitly stopped stopwatch is considered
411     * as stopped.
412     *
413     * @return boolean If the StopWatch is stopped.
414     * @since 3.2
415     */
416    public boolean isStopped() {
417        return runningState.isStopped();
418    }
419
420    /**
421     * Returns whether the StopWatch is suspended.
422     *
423     * @return boolean
424     *             If the StopWatch is suspended.
425     * @since 3.2
426     */
427    public boolean isSuspended() {
428        return runningState.isSuspended();
429    }
430
431    /**
432     * Resets the stopwatch. Stops it if need be.
433     *
434     * <p>
435     * This method clears the internal values to allow the object to be reused.
436     * </p>
437     */
438    public void reset() {
439        this.runningState = State.UNSTARTED;
440        this.splitState = SplitState.UNSPLIT;
441    }
442
443    /**
444     * Resumes the stopwatch after a suspend.
445     *
446     * <p>
447     * This method resumes the watch after it was suspended. The watch will not include time between the suspend and
448     * resume calls in the total time.
449     * </p>
450     *
451     * @throws IllegalStateException
452     *             if the StopWatch has not been suspended.
453     */
454    public void resume() {
455        if (this.runningState != State.SUSPENDED) {
456            throw new IllegalStateException("Stopwatch must be suspended to resume. ");
457        }
458        this.startTimeNanos += System.nanoTime() - this.stopTimeNanos;
459        this.runningState = State.RUNNING;
460    }
461
462    /**
463     * Splits the time.
464     *
465     * <p>
466     * This method sets the stop time of the watch to allow a time to be extracted. The start time is unaffected,
467     * enabling {@link #unsplit()} to continue the timing from the original start point.
468     * </p>
469     *
470     * @throws IllegalStateException
471     *             if the StopWatch is not running.
472     */
473    public void split() {
474        if (this.runningState != State.RUNNING) {
475            throw new IllegalStateException("Stopwatch is not running. ");
476        }
477        this.stopTimeNanos = System.nanoTime();
478        this.splitState = SplitState.SPLIT;
479    }
480
481    /**
482     * Starts the stopwatch.
483     *
484     * <p>
485     * This method starts a new timing session, clearing any previous values.
486     * </p>
487     *
488     * @throws IllegalStateException
489     *             if the StopWatch is already running.
490     */
491    public void start() {
492        if (this.runningState == State.STOPPED) {
493            throw new IllegalStateException("Stopwatch must be reset before being restarted. ");
494        }
495        if (this.runningState != State.UNSTARTED) {
496            throw new IllegalStateException("Stopwatch already started. ");
497        }
498        this.startTimeNanos = System.nanoTime();
499        this.startTimeMillis = System.currentTimeMillis();
500        this.runningState = State.RUNNING;
501    }
502
503    /**
504     * Stops the stopwatch.
505     *
506     * <p>
507     * This method ends a new timing session, allowing the time to be retrieved.
508     * </p>
509     *
510     * @throws IllegalStateException
511     *             if the StopWatch is not running.
512     */
513    public void stop() {
514        if (this.runningState != State.RUNNING && this.runningState != State.SUSPENDED) {
515            throw new IllegalStateException("Stopwatch is not running. ");
516        }
517        if (this.runningState == State.RUNNING) {
518            this.stopTimeNanos = System.nanoTime();
519            this.stopTimeMillis = System.currentTimeMillis();
520        }
521        this.runningState = State.STOPPED;
522    }
523
524    /**
525     * Suspends the stopwatch for later resumption.
526     *
527     * <p>
528     * This method suspends the watch until it is resumed. The watch will not include time between the suspend and
529     * resume calls in the total time.
530     * </p>
531     *
532     * @throws IllegalStateException
533     *             if the StopWatch is not currently running.
534     */
535    public void suspend() {
536        if (this.runningState != State.RUNNING) {
537            throw new IllegalStateException("Stopwatch must be running to suspend. ");
538        }
539        this.stopTimeNanos = System.nanoTime();
540        this.stopTimeMillis = System.currentTimeMillis();
541        this.runningState = State.SUSPENDED;
542    }
543
544    /**
545     * Gets a summary of the split time that the stopwatch recorded as a string.
546     *
547     * <p>
548     * The format used is ISO 8601-like, [<i>message</i> ]<i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
549     * </p>
550     *
551     * @return the split time as a String
552     * @since 2.1
553     * @since 3.10 Returns the prefix {@code "message "} if the message is set.
554     */
555    public String toSplitString() {
556        final String msgStr = Objects.toString(message, StringUtils.EMPTY);
557        final String formattedTime = formatSplitTime();
558        return msgStr.isEmpty() ? formattedTime : msgStr + StringUtils.SPACE + formattedTime;
559    }
560
561    /**
562     * Gets a summary of the time that the stopwatch recorded as a string.
563     *
564     * <p>
565     * The format used is ISO 8601-like, [<i>message</i> ]<i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
566     * </p>
567     *
568     * @return the time as a String
569     * @since 3.10 Returns the prefix {@code "message "} if the message is set.
570     */
571    @Override
572    public String toString() {
573        final String msgStr = Objects.toString(message, StringUtils.EMPTY);
574        final String formattedTime = formatTime();
575        return msgStr.isEmpty() ? formattedTime : msgStr + StringUtils.SPACE + formattedTime;
576    }
577
578    /**
579     * Removes a split.
580     *
581     * <p>
582     * This method clears the stop time. The start time is unaffected, enabling timing from the original start point to
583     * continue.
584     * </p>
585     *
586     * @throws IllegalStateException
587     *             if the StopWatch has not been split.
588     */
589    public void unsplit() {
590        if (this.splitState != SplitState.SPLIT) {
591            throw new IllegalStateException("Stopwatch has not been split. ");
592        }
593        this.splitState = SplitState.UNSPLIT;
594    }
595
596}