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 */
017package org.apache.camel.util;
018
019import java.util.Date;
020
021/**
022 * A very simple stop watch.
023 * <p/>
024 * This implementation is not thread safe and can only time one task at any given time.
025 *
026 * @version 
027 */
028public final class StopWatch {
029
030    private long start;
031
032    /**
033     * Starts the stop watch
034     */
035    public StopWatch() {
036        this.start = System.currentTimeMillis();
037    }
038
039    /**
040     * Starts the stop watch from the given timestamp
041     */
042    public StopWatch(Date startTimestamp) {
043        start = startTimestamp.getTime();
044    }
045
046    /**
047     * Creates the stop watch
048     *
049     * @param start whether it should start immediately
050     */
051    public StopWatch(boolean start) {
052        if (start) {
053            this.start = System.currentTimeMillis();
054        }
055    }
056
057    /**
058     * Starts or restarts the stop watch
059     */
060    public void restart() {
061        start = System.currentTimeMillis();
062    }
063
064    /**
065     * Reports the time taken (does not stop the stop watch)
066     *
067     * @return the time taken in millis.
068     * @deprecated use {@link #taken()}
069     */
070    @Deprecated
071    public long stop() {
072        return taken();
073    }
074
075    /**
076     * Returns the time taken in millis.
077     *
078     * @return time in millis, or <tt>0</tt> if not started yet.
079     */
080    public long taken() {
081        if (start > 0) {
082            return System.currentTimeMillis() - start;
083        } else {
084            return 0;
085        }
086    }
087
088}