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
018 package org.apache.commons.lang3.time;
019
020 /**
021 * <p>
022 * <code>StopWatch</code> provides a convenient API for timings.
023 * </p>
024 *
025 * <p>
026 * To start the watch, call {@link #start()}. At this point you can:
027 * </p>
028 * <ul>
029 * <li>{@link #split()} the watch to get the time whilst the watch continues in the background. {@link #unsplit()} will
030 * remove the effect of the split. At this point, these three options are available again.</li>
031 * <li>{@link #suspend()} the watch to pause it. {@link #resume()} allows the watch to continue. Any time between the
032 * suspend and resume will not be counted in the total. At this point, these three options are available again.</li>
033 * <li>{@link #stop()} the watch to complete the timing session.</li>
034 * </ul>
035 *
036 * <p>
037 * It is intended that the output methods {@link #toString()} and {@link #getTime()} should only be called after stop,
038 * split or suspend, however a suitable result will be returned at other points.
039 * </p>
040 *
041 * <p>
042 * NOTE: As from v2.1, the methods protect against inappropriate calls. Thus you cannot now call stop before start,
043 * resume before suspend or unsplit before split.
044 * </p>
045 *
046 * <p>
047 * 1. split(), suspend(), or stop() cannot be invoked twice<br />
048 * 2. unsplit() may only be called if the watch has been split()<br />
049 * 3. resume() may only be called if the watch has been suspend()<br />
050 * 4. start() cannot be called twice without calling reset()
051 * </p>
052 *
053 * <p>This class is not thread-safe</p>
054 *
055 * @author Apache Software Foundation
056 * @since 2.0
057 * @version $Id: StopWatch.java 959577 2010-07-01 09:48:23Z sebb $
058 */
059 public class StopWatch {
060
061 private static final long NANO_2_MILLIS = 1000000L;
062
063 // running states
064 private static final int STATE_UNSTARTED = 0;
065
066 private static final int STATE_RUNNING = 1;
067
068 private static final int STATE_STOPPED = 2;
069
070 private static final int STATE_SUSPENDED = 3;
071
072 // split state
073 private static final int STATE_UNSPLIT = 10;
074
075 private static final int STATE_SPLIT = 11;
076
077 /**
078 * The current running state of the StopWatch.
079 */
080 private int runningState = STATE_UNSTARTED;
081
082 /**
083 * Whether the stopwatch has a split time recorded.
084 */
085 private int splitState = STATE_UNSPLIT;
086
087 /**
088 * The start time.
089 */
090 private long startTime;
091
092 /**
093 * The start time in Millis - nanoTime is only for elapsed time so we
094 * need to also store the currentTimeMillis to maintain the old
095 * getStartTime API.
096 */
097 private long startTimeMillis;
098
099 /**
100 * The stop time.
101 */
102 private long stopTime;
103
104 /**
105 * <p>
106 * Constructor.
107 * </p>
108 */
109 public StopWatch() {
110 super();
111 }
112
113 /**
114 * <p>
115 * Start the stopwatch.
116 * </p>
117 *
118 * <p>
119 * This method starts a new timing session, clearing any previous values.
120 * </p>
121 *
122 * @throws IllegalStateException
123 * if the StopWatch is already running.
124 */
125 public void start() {
126 if (this.runningState == STATE_STOPPED) {
127 throw new IllegalStateException("Stopwatch must be reset before being restarted. ");
128 }
129 if (this.runningState != STATE_UNSTARTED) {
130 throw new IllegalStateException("Stopwatch already started. ");
131 }
132 this.startTime = System.nanoTime();
133 this.startTimeMillis = System.currentTimeMillis();
134 this.runningState = STATE_RUNNING;
135 }
136
137 /**
138 * <p>
139 * Stop the stopwatch.
140 * </p>
141 *
142 * <p>
143 * This method ends a new timing session, allowing the time to be retrieved.
144 * </p>
145 *
146 * @throws IllegalStateException
147 * if the StopWatch is not running.
148 */
149 public void stop() {
150 if (this.runningState != STATE_RUNNING && this.runningState != STATE_SUSPENDED) {
151 throw new IllegalStateException("Stopwatch is not running. ");
152 }
153 if (this.runningState == STATE_RUNNING) {
154 this.stopTime = System.nanoTime();
155 }
156 this.runningState = STATE_STOPPED;
157 }
158
159 /**
160 * <p>
161 * Resets the stopwatch. Stops it if need be.
162 * </p>
163 *
164 * <p>
165 * This method clears the internal values to allow the object to be reused.
166 * </p>
167 */
168 public void reset() {
169 this.runningState = STATE_UNSTARTED;
170 this.splitState = STATE_UNSPLIT;
171 }
172
173 /**
174 * <p>
175 * Split the time.
176 * </p>
177 *
178 * <p>
179 * This method sets the stop time of the watch to allow a time to be extracted. The start time is unaffected,
180 * enabling {@link #unsplit()} to continue the timing from the original start point.
181 * </p>
182 *
183 * @throws IllegalStateException
184 * if the StopWatch is not running.
185 */
186 public void split() {
187 if (this.runningState != STATE_RUNNING) {
188 throw new IllegalStateException("Stopwatch is not running. ");
189 }
190 this.stopTime = System.nanoTime();
191 this.splitState = STATE_SPLIT;
192 }
193
194 /**
195 * <p>
196 * Remove a split.
197 * </p>
198 *
199 * <p>
200 * This method clears the stop time. The start time is unaffected, enabling timing from the original start point to
201 * continue.
202 * </p>
203 *
204 * @throws IllegalStateException
205 * if the StopWatch has not been split.
206 */
207 public void unsplit() {
208 if (this.splitState != STATE_SPLIT) {
209 throw new IllegalStateException("Stopwatch has not been split. ");
210 }
211 this.splitState = STATE_UNSPLIT;
212 }
213
214 /**
215 * <p>
216 * Suspend the stopwatch for later resumption.
217 * </p>
218 *
219 * <p>
220 * This method suspends the watch until it is resumed. The watch will not include time between the suspend and
221 * resume calls in the total time.
222 * </p>
223 *
224 * @throws IllegalStateException
225 * if the StopWatch is not currently running.
226 */
227 public void suspend() {
228 if (this.runningState != STATE_RUNNING) {
229 throw new IllegalStateException("Stopwatch must be running to suspend. ");
230 }
231 this.stopTime = System.nanoTime();
232 this.runningState = STATE_SUSPENDED;
233 }
234
235 /**
236 * <p>
237 * Resume the stopwatch after a suspend.
238 * </p>
239 *
240 * <p>
241 * This method resumes the watch after it was suspended. The watch will not include time between the suspend and
242 * resume calls in the total time.
243 * </p>
244 *
245 * @throws IllegalStateException
246 * if the StopWatch has not been suspended.
247 */
248 public void resume() {
249 if (this.runningState != STATE_SUSPENDED) {
250 throw new IllegalStateException("Stopwatch must be suspended to resume. ");
251 }
252 this.startTime += (System.nanoTime() - this.stopTime);
253 this.runningState = STATE_RUNNING;
254 }
255
256 /**
257 * <p>
258 * Get the time on the stopwatch.
259 * </p>
260 *
261 * <p>
262 * This is either the time between the start and the moment this method is called, or the amount of time between
263 * start and stop.
264 * </p>
265 *
266 * @return the time in milliseconds
267 */
268 public long getTime() {
269 return getNanoTime() / NANO_2_MILLIS;
270 }
271 /**
272 * <p>
273 * Get the time on the stopwatch in nanoseconds.
274 * </p>
275 *
276 * <p>
277 * This is either the time between the start and the moment this method is called, or the amount of time between
278 * start and stop.
279 * </p>
280 *
281 * @return the time in nanoseconds
282 * @since 3.0
283 */
284 public long getNanoTime() {
285 if (this.runningState == STATE_STOPPED || this.runningState == STATE_SUSPENDED) {
286 return this.stopTime - this.startTime;
287 } else if (this.runningState == STATE_UNSTARTED) {
288 return 0;
289 } else if (this.runningState == STATE_RUNNING) {
290 return System.nanoTime() - this.startTime;
291 }
292 throw new RuntimeException("Illegal running state has occured. ");
293 }
294
295 /**
296 * <p>
297 * Get the split time on the stopwatch.
298 * </p>
299 *
300 * <p>
301 * This is the time between start and latest split.
302 * </p>
303 *
304 * @return the split time in milliseconds
305 *
306 * @throws IllegalStateException
307 * if the StopWatch has not yet been split.
308 * @since 2.1
309 */
310 public long getSplitTime() {
311 return getSplitNanoTime() / NANO_2_MILLIS;
312 }
313 /**
314 * <p>
315 * Get the split time on the stopwatch in nanoseconds.
316 * </p>
317 *
318 * <p>
319 * This is the time between start and latest split.
320 * </p>
321 *
322 * @return the split time in nanoseconds
323 *
324 * @throws IllegalStateException
325 * if the StopWatch has not yet been split.
326 * @since 3.0
327 */
328 public long getSplitNanoTime() {
329 if (this.splitState != STATE_SPLIT) {
330 throw new IllegalStateException("Stopwatch must be split to get the split time. ");
331 }
332 return this.stopTime - this.startTime;
333 }
334
335 /**
336 * Returns the time this stopwatch was started.
337 *
338 * @return the time this stopwatch was started
339 * @throws IllegalStateException
340 * if this StopWatch has not been started
341 * @since 2.4
342 */
343 public long getStartTime() {
344 if (this.runningState == STATE_UNSTARTED) {
345 throw new IllegalStateException("Stopwatch has not been started");
346 }
347 // System.nanoTime is for elapsed time
348 return this.startTimeMillis;
349 }
350
351 /**
352 * <p>
353 * Gets a summary of the time that the stopwatch recorded as a string.
354 * </p>
355 *
356 * <p>
357 * The format used is ISO8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
358 * </p>
359 *
360 * @return the time as a String
361 */
362 @Override
363 public String toString() {
364 return DurationFormatUtils.formatDurationHMS(getTime());
365 }
366
367 /**
368 * <p>
369 * Gets a summary of the split time that the stopwatch recorded as a string.
370 * </p>
371 *
372 * <p>
373 * The format used is ISO8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
374 * </p>
375 *
376 * @return the split time as a String
377 * @since 2.1
378 */
379 public String toSplitString() {
380 return DurationFormatUtils.formatDurationHMS(getSplitTime());
381 }
382
383 }