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 * @since 2.0
056 * @version $Id: StopWatch.java 1088899 2011-04-05 05:31:27Z bayard $
057 */
058 public class StopWatch {
059
060 private static final long NANO_2_MILLIS = 1000000L;
061
062 // running states
063 private static final int STATE_UNSTARTED = 0;
064
065 private static final int STATE_RUNNING = 1;
066
067 private static final int STATE_STOPPED = 2;
068
069 private static final int STATE_SUSPENDED = 3;
070
071 // split state
072 private static final int STATE_UNSPLIT = 10;
073
074 private static final int STATE_SPLIT = 11;
075
076 /**
077 * The current running state of the StopWatch.
078 */
079 private int runningState = STATE_UNSTARTED;
080
081 /**
082 * Whether the stopwatch has a split time recorded.
083 */
084 private int splitState = STATE_UNSPLIT;
085
086 /**
087 * The start time.
088 */
089 private long startTime;
090
091 /**
092 * The start time in Millis - nanoTime is only for elapsed time so we
093 * need to also store the currentTimeMillis to maintain the old
094 * getStartTime API.
095 */
096 private long startTimeMillis;
097
098 /**
099 * The stop time.
100 */
101 private long stopTime;
102
103 /**
104 * <p>
105 * Constructor.
106 * </p>
107 */
108 public StopWatch() {
109 super();
110 }
111
112 /**
113 * <p>
114 * Start the stopwatch.
115 * </p>
116 *
117 * <p>
118 * This method starts a new timing session, clearing any previous values.
119 * </p>
120 *
121 * @throws IllegalStateException
122 * if the StopWatch is already running.
123 */
124 public void start() {
125 if (this.runningState == STATE_STOPPED) {
126 throw new IllegalStateException("Stopwatch must be reset before being restarted. ");
127 }
128 if (this.runningState != STATE_UNSTARTED) {
129 throw new IllegalStateException("Stopwatch already started. ");
130 }
131 this.startTime = System.nanoTime();
132 this.startTimeMillis = System.currentTimeMillis();
133 this.runningState = STATE_RUNNING;
134 }
135
136 /**
137 * <p>
138 * Stop the stopwatch.
139 * </p>
140 *
141 * <p>
142 * This method ends a new timing session, allowing the time to be retrieved.
143 * </p>
144 *
145 * @throws IllegalStateException
146 * if the StopWatch is not running.
147 */
148 public void stop() {
149 if (this.runningState != STATE_RUNNING && this.runningState != STATE_SUSPENDED) {
150 throw new IllegalStateException("Stopwatch is not running. ");
151 }
152 if (this.runningState == STATE_RUNNING) {
153 this.stopTime = System.nanoTime();
154 }
155 this.runningState = STATE_STOPPED;
156 }
157
158 /**
159 * <p>
160 * Resets the stopwatch. Stops it if need be.
161 * </p>
162 *
163 * <p>
164 * This method clears the internal values to allow the object to be reused.
165 * </p>
166 */
167 public void reset() {
168 this.runningState = STATE_UNSTARTED;
169 this.splitState = STATE_UNSPLIT;
170 }
171
172 /**
173 * <p>
174 * Split the time.
175 * </p>
176 *
177 * <p>
178 * This method sets the stop time of the watch to allow a time to be extracted. The start time is unaffected,
179 * enabling {@link #unsplit()} to continue the timing from the original start point.
180 * </p>
181 *
182 * @throws IllegalStateException
183 * if the StopWatch is not running.
184 */
185 public void split() {
186 if (this.runningState != STATE_RUNNING) {
187 throw new IllegalStateException("Stopwatch is not running. ");
188 }
189 this.stopTime = System.nanoTime();
190 this.splitState = STATE_SPLIT;
191 }
192
193 /**
194 * <p>
195 * Remove a split.
196 * </p>
197 *
198 * <p>
199 * This method clears the stop time. The start time is unaffected, enabling timing from the original start point to
200 * continue.
201 * </p>
202 *
203 * @throws IllegalStateException
204 * if the StopWatch has not been split.
205 */
206 public void unsplit() {
207 if (this.splitState != STATE_SPLIT) {
208 throw new IllegalStateException("Stopwatch has not been split. ");
209 }
210 this.splitState = STATE_UNSPLIT;
211 }
212
213 /**
214 * <p>
215 * Suspend the stopwatch for later resumption.
216 * </p>
217 *
218 * <p>
219 * This method suspends the watch until it is resumed. The watch will not include time between the suspend and
220 * resume calls in the total time.
221 * </p>
222 *
223 * @throws IllegalStateException
224 * if the StopWatch is not currently running.
225 */
226 public void suspend() {
227 if (this.runningState != STATE_RUNNING) {
228 throw new IllegalStateException("Stopwatch must be running to suspend. ");
229 }
230 this.stopTime = System.nanoTime();
231 this.runningState = STATE_SUSPENDED;
232 }
233
234 /**
235 * <p>
236 * Resume the stopwatch after a suspend.
237 * </p>
238 *
239 * <p>
240 * This method resumes the watch after it was suspended. The watch will not include time between the suspend and
241 * resume calls in the total time.
242 * </p>
243 *
244 * @throws IllegalStateException
245 * if the StopWatch has not been suspended.
246 */
247 public void resume() {
248 if (this.runningState != STATE_SUSPENDED) {
249 throw new IllegalStateException("Stopwatch must be suspended to resume. ");
250 }
251 this.startTime += (System.nanoTime() - this.stopTime);
252 this.runningState = STATE_RUNNING;
253 }
254
255 /**
256 * <p>
257 * Get the time on the stopwatch.
258 * </p>
259 *
260 * <p>
261 * This is either the time between the start and the moment this method is called, or the amount of time between
262 * start and stop.
263 * </p>
264 *
265 * @return the time in milliseconds
266 */
267 public long getTime() {
268 return getNanoTime() / NANO_2_MILLIS;
269 }
270 /**
271 * <p>
272 * Get the time on the stopwatch in nanoseconds.
273 * </p>
274 *
275 * <p>
276 * This is either the time between the start and the moment this method is called, or the amount of time between
277 * start and stop.
278 * </p>
279 *
280 * @return the time in nanoseconds
281 * @since 3.0
282 */
283 public long getNanoTime() {
284 if (this.runningState == STATE_STOPPED || this.runningState == STATE_SUSPENDED) {
285 return this.stopTime - this.startTime;
286 } else if (this.runningState == STATE_UNSTARTED) {
287 return 0;
288 } else if (this.runningState == STATE_RUNNING) {
289 return System.nanoTime() - this.startTime;
290 }
291 throw new RuntimeException("Illegal running state has occured. ");
292 }
293
294 /**
295 * <p>
296 * Get the split time on the stopwatch.
297 * </p>
298 *
299 * <p>
300 * This is the time between start and latest split.
301 * </p>
302 *
303 * @return the split time in milliseconds
304 *
305 * @throws IllegalStateException
306 * if the StopWatch has not yet been split.
307 * @since 2.1
308 */
309 public long getSplitTime() {
310 return getSplitNanoTime() / NANO_2_MILLIS;
311 }
312 /**
313 * <p>
314 * Get the split time on the stopwatch in nanoseconds.
315 * </p>
316 *
317 * <p>
318 * This is the time between start and latest split.
319 * </p>
320 *
321 * @return the split time in nanoseconds
322 *
323 * @throws IllegalStateException
324 * if the StopWatch has not yet been split.
325 * @since 3.0
326 */
327 public long getSplitNanoTime() {
328 if (this.splitState != STATE_SPLIT) {
329 throw new IllegalStateException("Stopwatch must be split to get the split time. ");
330 }
331 return this.stopTime - this.startTime;
332 }
333
334 /**
335 * Returns the time this stopwatch was started.
336 *
337 * @return the time this stopwatch was started
338 * @throws IllegalStateException
339 * 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 * <p>
352 * Gets a summary of the time that the stopwatch recorded as a string.
353 * </p>
354 *
355 * <p>
356 * The format used is ISO8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
357 * </p>
358 *
359 * @return the time as a String
360 */
361 @Override
362 public String toString() {
363 return DurationFormatUtils.formatDurationHMS(getTime());
364 }
365
366 /**
367 * <p>
368 * Gets a summary of the split time that the stopwatch recorded as a string.
369 * </p>
370 *
371 * <p>
372 * The format used is ISO8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
373 * </p>
374 *
375 * @return the split time as a String
376 * @since 2.1
377 */
378 public String toSplitString() {
379 return DurationFormatUtils.formatDurationHMS(getSplitTime());
380 }
381
382 }