1 package org.e2etrace.timer;
2
3 /*
4 * Copyright 2006 Gunther Popp
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 /**
20 * Timer Implementation with high accuracy regardless of the operating system.
21 * <p>
22 *
23 * New JDKs provide an API for measuring time intervals that works accurate on
24 * all operating systems. To be exact: It guarantees the accuracy the operating
25 * system is able to deliver. In most to all cases this should be about 1-2ms.
26 * <p>
27 *
28 * @author Gunther Popp
29 */
30 public class ExactTimer implements ITimer {
31
32 private long duration = -1;
33 private long start = -1;
34
35 /**
36 * Constructor. New instances can only be created by
37 * {@link DefaultTimerFactory}
38 */
39 ExactTimer() {
40
41 }
42
43 /** {@inheritDoc} */
44 public void start() {
45 start = System.nanoTime();
46
47 }
48
49 /** {@inheritDoc} */
50 public long measure() {
51 if (start > 0) {
52 duration = ((System.nanoTime()) - start) / 1000000;
53 }
54
55 return duration;
56
57 }
58
59 }