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