| /* |
| * Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com> |
| * and other copyright owners as documented in the project's IP log. |
| * |
| * This program and the accompanying materials are made available |
| * under the terms of the Eclipse Distribution License v1.0 which |
| * accompanies this distribution, is reproduced below, and is |
| * available at http://www.eclipse.org/org/documents/edl-v10.php |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * - Neither the name of the Eclipse Foundation, Inc. nor the |
| * names of its contributors may be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
| * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package org.eclipse.jgit.util; |
| |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.ThreadMXBean; |
| |
| /** |
| * A simple stopwatch which measures elapsed CPU time of the current thread. CPU |
| * time is the time spent on executing your own code plus the time spent on |
| * executing operating system calls triggered by your application. |
| * <p> |
| * This stopwatch needs a VM which supports getting CPU Time information for the |
| * current thread. The static method createInstance() will take care to return |
| * only a new instance of this class if the VM is capable of returning CPU time. |
| */ |
| public class CPUTimeStopWatch { |
| private long start; |
| |
| private static ThreadMXBean mxBean=ManagementFactory.getThreadMXBean(); |
| |
| /** |
| * use this method instead of the constructor to be sure that the underlying |
| * VM provides all features needed by this class. |
| * |
| * @return a new instance of {@link #CPUTimeStopWatch()} or |
| * <code>null</code> if the VM does not support getting CPU time |
| * information |
| */ |
| public static CPUTimeStopWatch createInstance() { |
| return mxBean.isCurrentThreadCpuTimeSupported() ? new CPUTimeStopWatch() |
| : null; |
| } |
| |
| /** |
| * Starts the stopwatch. If the stopwatch is already started this will |
| * restart the stopwatch. |
| */ |
| public void start() { |
| start = mxBean.getCurrentThreadCpuTime(); |
| } |
| |
| /** |
| * Stops the stopwatch and return the elapsed CPU time in nanoseconds. |
| * Should be called only on started stopwatches. |
| * |
| * @return the elapsed CPU time in nanoseconds. When called on non-started |
| * stopwatches (either because {@link #start()} was never called or |
| * {@link #stop()} was called after the last call to |
| * {@link #start()}) this method will return 0. |
| */ |
| public long stop() { |
| long cpuTime = readout(); |
| start = 0; |
| return cpuTime; |
| } |
| |
| /** |
| * Return the elapsed CPU time in nanoseconds. In contrast to |
| * {@link #stop()} the stopwatch will continue to run after this call. |
| * |
| * @return the elapsed CPU time in nanoseconds. When called on non-started |
| * stopwatches (either because {@link #start()} was never called or |
| * {@link #stop()} was called after the last call to |
| * {@link #start()}) this method will return 0. |
| */ |
| public long readout() { |
| return (start == 0) ? 0 : mxBean.getCurrentThreadCpuTime() - start; |
| } |
| } |