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 */ 024public final class StopWatch { 025 026 private long start; 027 private long stop; 028 029 /** 030 * Starts the stop watch 031 */ 032 public StopWatch() { 033 this(true); 034 } 035 036 /** 037 * Creates the stop watch 038 * 039 * @param started whether it should start immediately 040 */ 041 public StopWatch(boolean started) { 042 if (started) { 043 restart(); 044 } 045 } 046 047 /** 048 * Starts or restarts the stop watch 049 */ 050 public void restart() { 051 start = System.currentTimeMillis(); 052 stop = 0; 053 } 054 055 /** 056 * Stops the stop watch 057 * 058 * @return the time taken in milliseconds. 059 */ 060 public long stop() { 061 stop = System.currentTimeMillis(); 062 return taken(); 063 } 064 065 /** 066 * Returns the time taken in milliseconds. 067 * 068 * @return time in milliseconds 069 */ 070 public long taken() { 071 if (start > 0 && stop > 0) { 072 return stop - start; 073 } else if (start > 0) { 074 return System.currentTimeMillis() - start; 075 } else { 076 return 0; 077 } 078 } 079}