Stopwatch.java revision 1870:4aa2e64eff30 
1/*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24package jdk.test.failurehandler;
25
26public final class Stopwatch {
27    protected boolean isResultAvailable;
28    protected boolean isRunning;
29
30    private long startTimeNs;
31    private long stopTimeNs;
32
33    public Stopwatch() {
34        isResultAvailable = false;
35    }
36
37    /**
38     * Starts measuring time.
39     */
40    public void start() {
41        startTimeNs = System.nanoTime();
42        isRunning = true;
43    }
44
45    /**
46     * Stops measuring time.
47     */
48    public void stop() {
49        if (!isRunning) {
50            throw new IllegalStateException(" hasn't been started");
51        }
52        stopTimeNs = System.nanoTime();
53        isRunning = false;
54        isResultAvailable = true;
55    }
56
57    /**
58     * @return time in nanoseconds measured between
59     * calls of {@link #start()} and {@link #stop()} methods.
60     *
61     * @throws IllegalStateException if called without preceding
62     * {@link #start()} {@link #stop()} method
63     */
64    public long getElapsedTimeNs() {
65        if (isRunning) {
66            throw new IllegalStateException("hasn't been stopped");
67        }
68        if (!isResultAvailable) {
69            throw new IllegalStateException("was not run");
70        }
71        return stopTimeNs - startTimeNs;
72    }
73}
74