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Java mxbean getProcessCpuLoad parallel test
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| import javax.management.MBeanServer; | |
| import javax.management.ObjectName; | |
| import java.lang.management.ManagementFactory; | |
| import java.lang.management.OperatingSystemMXBean; | |
| import java.lang.reflect.InvocationTargetException; | |
| import java.lang.reflect.Method; | |
| import java.util.Arrays; | |
| import java.util.DoubleSummaryStatistics; | |
| import java.util.List; | |
| import java.util.concurrent.Executors; | |
| import java.util.concurrent.TimeUnit; | |
| import static java.util.Objects.requireNonNull; | |
| public class CpuTest { | |
| private static MBeanServer platformMBeanServer; | |
| private static OperatingSystemMXBean operatingSystemMXBean; | |
| private static ObjectName objectName; | |
| private static OperatingSystemMXBean operatingSystemBean; | |
| private static Class<?> operatingSystemBeanClass; | |
| private static Method systemCpuUsage; | |
| // trying caching from ProcessorMetrics | |
| private static Method processCpuUsage; | |
| private static final List<String> OPERATING_SYSTEM_BEAN_CLASS_NAMES = Arrays.asList( | |
| "com.ibm.lang.management.OperatingSystemMXBean", // J9 | |
| "com.sun.management.OperatingSystemMXBean" // HotSpot | |
| ); | |
| public static void main(String[] args) { | |
| DoubleSummaryStatistics doubleSummaryStatistics = new DoubleSummaryStatistics(); | |
| Runnable cpuLoadUsingMxBean = () -> { | |
| Double processCpuLoad = invoke(processCpuUsage); | |
| doubleSummaryStatistics.accept(processCpuLoad); | |
| System.out.println(Thread.currentThread().getName() + " cpu load: " + String.format("%.2f", processCpuLoad) + " / " + doubleSummaryStatistics.getAverage()); | |
| }; | |
| /* | |
| platformMBeanServer = getPlatformMBeanServer(); | |
| operatingSystemMXBean = getOperatingSystemMXBean(); | |
| objectName = operatingSystemMXBean.getObjectName(); | |
| */ | |
| operatingSystemBean = ManagementFactory.getOperatingSystemMXBean(); | |
| operatingSystemBeanClass = getFirstClassFound(OPERATING_SYSTEM_BEAN_CLASS_NAMES); | |
| processCpuUsage = detectMethod("getProcessCpuLoad"); | |
| var executorService = Executors.newScheduledThreadPool(10); | |
| executorService.scheduleAtFixedRate(cpuLoadUsingMxBean, 0, 5, TimeUnit.SECONDS); | |
| // executorService.scheduleAtFixedRate(cpuLoadUsingMxBean, 0, 1, TimeUnit.SECONDS); | |
| // executorService.scheduleAtFixedRate(cpuLoadUsingMxBean, 0, 1, TimeUnit.SECONDS); | |
| } | |
| private static double invoke( Method method) { | |
| try { | |
| return method != null ? toDouble((Number) method.invoke(operatingSystemBean)) : Double.NaN; | |
| } | |
| catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) { | |
| return Double.NaN; | |
| } | |
| } | |
| private static double toDouble(Number number) { | |
| return number != null ? number.doubleValue() : Double.NaN; | |
| } | |
| private static Class<?> getFirstClassFound(List<String> classNames) { | |
| for (String className : classNames) { | |
| try { | |
| return Class.forName(className); | |
| } | |
| catch (ClassNotFoundException ignore) { | |
| } | |
| } | |
| return null; | |
| } | |
| private static Method detectMethod(String name) { | |
| requireNonNull(name); | |
| if (operatingSystemBeanClass == null) { | |
| return null; | |
| } | |
| try { | |
| // ensure the Bean we have is actually an instance of the interface | |
| Object ignored = operatingSystemBeanClass.cast(operatingSystemBean); | |
| return operatingSystemBeanClass.getMethod(name); | |
| } | |
| catch (ClassCastException | NoSuchMethodException | SecurityException e) { | |
| return null; | |
| } | |
| } | |
| public static Double getProcessCpuLoad() { | |
| return getMXBeanValueAsDouble("ProcessCpuLoad"); | |
| } | |
| private static Double getMXBeanValueAsDouble(String name) { | |
| double value = ((Number) getMXBeanValue(name)).doubleValue(); | |
| if (!Double.isNaN(value)) { | |
| return value; | |
| } | |
| return -1D; | |
| } | |
| private static OperatingSystemMXBean getOperatingSystemMXBean() { | |
| try { | |
| return ManagementFactory.getOperatingSystemMXBean(); | |
| } catch (ExceptionInInitializerError | NoClassDefFoundError e) { | |
| return null; | |
| } | |
| } | |
| private static MBeanServer getPlatformMBeanServer() { | |
| try { | |
| return ManagementFactory.getPlatformMBeanServer(); | |
| } catch (ExceptionInInitializerError | NoClassDefFoundError e) { | |
| return null; | |
| } | |
| } | |
| static <O> O getMXBeanValue(String name) { | |
| try { | |
| final Object attribute = platformMBeanServer.getAttribute(objectName, name); | |
| return (O) attribute; | |
| } catch (Throwable ex) { | |
| throw new IllegalStateException(ex); | |
| } | |
| } | |
| } |
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