45 lines
1.2 KiB
Java
45 lines
1.2 KiB
Java
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/*************************************************************************
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* Compilation: javac Stopwatch.java
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*
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*
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*************************************************************************/
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import java.lang.management.ThreadMXBean;
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import java.lang.management.ManagementFactory;
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/**
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* The StopwatchCPU data type is for measuring
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* the CPU time used during a programming task.
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*
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* See {@link Stopwatch} for a version that measures wall-clock time
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* (the real time that elapses).
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*
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* @author Josh Hug
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* @author Robert Sedgewick
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* @author Kevin Wayne
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*/
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public class StopwatchCPU {
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private final ThreadMXBean threadTimer;
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private final long start;
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private static final double NANOSECONDS_PER_SECOND = 1000000000;
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/**
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* Initialize a stopwatch object.
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*/
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public StopwatchCPU() {
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threadTimer = ManagementFactory.getThreadMXBean();
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start = threadTimer.getCurrentThreadCpuTime();
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}
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/**
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* Returns the elapsed CPU time (in seconds) since the object was created.
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*/
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public double elapsedTime() {
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long now = threadTimer.getCurrentThreadCpuTime();
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return (now - start) / NANOSECONDS_PER_SECOND;
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}
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}
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