    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.lang.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 1056988 2011-01-09 17:58:53Z niallp $
    058     */
    059    public class StopWatch {
    060
    061        // running states
    062        private static final int STATE_UNSTARTED = 0;
    063
    064        private static final int STATE_RUNNING = 1;
    065
    066        private static final int STATE_STOPPED = 2;
    067
    068        private static final int STATE_SUSPENDED = 3;
    069
    070        // split state
    071        private static final int STATE_UNSPLIT = 10;
    072
    073        private static final int STATE_SPLIT = 11;
    074
    075        /**
    076         * The current running state of the StopWatch.
    077         */
    078        private int runningState = STATE_UNSTARTED;
    079
    080        /**
    081         * Whether the stopwatch has a split time recorded.
    082         */
    083        private int splitState = STATE_UNSPLIT;
    084
    085        /**
    086         * The start time.
    087         */
    088        private long startTime = -1;
    089
    090        /**
    091         * The stop time.
    092         */
    093        private long stopTime = -1;
    094
    095        /**
    096         * <p>
    097         * Constructor.
    098         * </p>
    099         */
    100        public StopWatch() {
    101            super();
    102        }
    103
    104        /**
    105         * <p>
    106         * Start the stopwatch.
    107         * </p>
    108         *
    109         * <p>
    110         * This method starts a new timing session, clearing any previous values.
    111         * </p>
    112         *
    113         * @throws IllegalStateException
    114         *             if the StopWatch is already running.
    115         */
    116        public void start() {
    117            if (this.runningState == STATE_STOPPED) {
    118                throw new IllegalStateException("Stopwatch must be reset before being restarted. ");
    119            }
    120            if (this.runningState != STATE_UNSTARTED) {
    121                throw new IllegalStateException("Stopwatch already started. ");
    122            }
    123            this.stopTime = -1;
    124            this.startTime = System.currentTimeMillis();
    125            this.runningState = STATE_RUNNING;
    126        }
    127
    128        /**
    129         * <p>
    130         * Stop the stopwatch.
    131         * </p>
    132         *
    133         * <p>
    134         * This method ends a new timing session, allowing the time to be retrieved.
    135         * </p>
    136         *
    137         * @throws IllegalStateException
    138         *             if the StopWatch is not running.
    139         */
    140        public void stop() {
    141            if (this.runningState != STATE_RUNNING && this.runningState != STATE_SUSPENDED) {
    142                throw new IllegalStateException("Stopwatch is not running. ");
    143            }
    144            if (this.runningState == STATE_RUNNING) {
    145                this.stopTime = System.currentTimeMillis();
    146            }
    147            this.runningState = STATE_STOPPED;
    148        }
    149
    150        /**
    151         * <p>
    152         * Resets the stopwatch. Stops it if need be.
    153         * </p>
    154         *
    155         * <p>
    156         * This method clears the internal values to allow the object to be reused.
    157         * </p>
    158         */
    159        public void reset() {
    160            this.runningState = STATE_UNSTARTED;
    161            this.splitState = STATE_UNSPLIT;
    162            this.startTime = -1;
    163            this.stopTime = -1;
    164        }
    165
    166        /**
    167         * <p>
    168         * Split the time.
    169         * </p>
    170         *
    171         * <p>
    172         * This method sets the stop time of the watch to allow a time to be extracted. The start time is unaffected,
    173         * enabling {@link #unsplit()} to continue the timing from the original start point.
    174         * </p>
    175         *
    176         * @throws IllegalStateException
    177         *             if the StopWatch is not running.
    178         */
    179        public void split() {
    180            if (this.runningState != STATE_RUNNING) {
    181                throw new IllegalStateException("Stopwatch is not running. ");
    182            }
    183            this.stopTime = System.currentTimeMillis();
    184            this.splitState = STATE_SPLIT;
    185        }
    186
    187        /**
    188         * <p>
    189         * Remove a split.
    190         * </p>
    191         *
    192         * <p>
    193         * This method clears the stop time. The start time is unaffected, enabling timing from the original start point to
    194         * continue.
    195         * </p>
    196         *
    197         * @throws IllegalStateException
    198         *             if the StopWatch has not been split.
    199         */
    200        public void unsplit() {
    201            if (this.splitState != STATE_SPLIT) {
    202                throw new IllegalStateException("Stopwatch has not been split. ");
    203            }
    204            this.stopTime = -1;
    205            this.splitState = STATE_UNSPLIT;
    206        }
    207
    208        /**
    209         * <p>
    210         * Suspend the stopwatch for later resumption.
    211         * </p>
    212         *
    213         * <p>
    214         * This method suspends the watch until it is resumed. The watch will not include time between the suspend and
    215         * resume calls in the total time.
    216         * </p>
    217         *
    218         * @throws IllegalStateException
    219         *             if the StopWatch is not currently running.
    220         */
    221        public void suspend() {
    222            if (this.runningState != STATE_RUNNING) {
    223                throw new IllegalStateException("Stopwatch must be running to suspend. ");
    224            }
    225            this.stopTime = System.currentTimeMillis();
    226            this.runningState = STATE_SUSPENDED;
    227        }
    228
    229        /**
    230         * <p>
    231         * Resume the stopwatch after a suspend.
    232         * </p>
    233         *
    234         * <p>
    235         * This method resumes the watch after it was suspended. The watch will not include time between the suspend and
    236         * resume calls in the total time.
    237         * </p>
    238         *
    239         * @throws IllegalStateException
    240         *             if the StopWatch has not been suspended.
    241         */
    242        public void resume() {
    243            if (this.runningState != STATE_SUSPENDED) {
    244                throw new IllegalStateException("Stopwatch must be suspended to resume. ");
    245            }
    246            this.startTime += (System.currentTimeMillis() - this.stopTime);
    247            this.stopTime = -1;
    248            this.runningState = STATE_RUNNING;
    249        }
    250
    251        /**
    252         * <p>
    253         * Get the time on the stopwatch.
    254         * </p>
    255         *
    256         * <p>
    257         * This is either the time between the start and the moment this method is called, or the amount of time between
    258         * start and stop.
    259         * </p>
    260         *
    261         * @return the time in milliseconds
    262         */
    263        public long getTime() {
    264            if (this.runningState == STATE_STOPPED || this.runningState == STATE_SUSPENDED) {
    265                return this.stopTime - this.startTime;
    266            } else if (this.runningState == STATE_UNSTARTED) {
    267                return 0;
    268            } else if (this.runningState == STATE_RUNNING) {
    269                return System.currentTimeMillis() - this.startTime;
    270            }
    271            throw new RuntimeException("Illegal running state has occured. ");
    272        }
    273
    274        /**
    275         * <p>
    276         * Get the split time on the stopwatch.
    277         * </p>
    278         *
    279         * <p>
    280         * This is the time between start and latest split.
    281         * </p>
    282         *
    283         * @return the split time in milliseconds
    284         *
    285         * @throws IllegalStateException
    286         *             if the StopWatch has not yet been split.
    287         * @since 2.1
    288         */
    289        public long getSplitTime() {
    290            if (this.splitState != STATE_SPLIT) {
    291                throw new IllegalStateException("Stopwatch must be split to get the split time. ");
    292            }
    293            return this.stopTime - this.startTime;
    294        }
    295
    296        /**
    297         * Returns the time this stopwatch was started.
    298         *
    299         * @return the time this stopwatch was started
    300         * @throws IllegalStateException
    301         *             if this StopWatch has not been started
    302         * @since 2.4
    303         */
    304        public long getStartTime() {
    305            if (this.runningState == STATE_UNSTARTED) {
    306                throw new IllegalStateException("Stopwatch has not been started");
    307            }
    308            return this.startTime;
    309        }
    310
    311        /**
    312         * <p>
    313         * Gets a summary of the time that the stopwatch recorded as a string.
    314         * </p>
    315         *
    316         * <p>
    317         * The format used is ISO8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
    318         * </p>
    319         *
    320         * @return the time as a String
    321         */
    322        public String toString() {
    323            return DurationFormatUtils.formatDurationHMS(getTime());
    324        }
    325
    326        /**
    327         * <p>
    328         * Gets a summary of the split time that the stopwatch recorded as a string.
    329         * </p>
    330         *
    331         * <p>
    332         * The format used is ISO8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
    333         * </p>
    334         *
    335         * @return the split time as a String
    336         * @since 2.1
    337         */
    338        public String toSplitString() {
    339            return DurationFormatUtils.formatDurationHMS(getSplitTime());
    340        }
    341
    342    }