123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111 |
- /*
- * 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;
- }
- }
|