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Timers.java

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package org.netbeans.lib.profiler.server.system;

import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;


/**
 * Provides methods for obtaining various high-resolution system times.
 * A version for JDK 1.5
 *
 * @author  Misha Dmitriev
 */
public class Timers {
    //~ Static fields/initializers -----------------------------------------------------------------------------------------------

    private static ThreadMXBean mxbean;

    //~ Methods ------------------------------------------------------------------------------------------------------------------

    /**
     * "counts" instead of nanoseconds in this method are for compatibility with the previous
     * versions of JFluid, that call a native method for system timer, which, in turn, returns
     * the result in sub-microsecond "counts" on Windows.
     */
00065     public static long getCurrentTimeInCounts() {
        return System.nanoTime();
    }

    public static long getNoOfCountsInSecond() {
        return 1000000000;
    }

    public static native long getThreadCPUTimeInNanos();

    /**
     * This is relevant only on Solaris. By default, the resolution of the thread local CPU timer is 10 ms. If we enable
     * micro state accounting, it enables significantly (but possibly at a price of some overhead). So I turn it on only
     * when thread CPU timestamps are really collected.
     */
    public static native void enableMicrostateAccounting(boolean v);

    /** Should be called at earliest possible time */
00083     public static void initialize() {
        mxbean = ManagementFactory.getThreadMXBean();
        getThreadCPUTimeInNanos();
    }

    /**
     * WORKS ONLY ON UNIX, calls nanosleep(). On Solaris, this is more precise than the built-in Thread.sleep() call
     * implementation that, at least in JDK 1.4.2, goes to select(3C). On Linux, it should be more precise, but it
     * turns out that nanosleep() in this OS, at least in version 7.3 that I tested, has a resolution of at least 20ms.
     * This seems to be a known issue; hopefully they fix it in future.
     */
    public static native void osSleep(int ns);
}

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