org.conqat.lib.commons.system

Class PerformanceMonitor

java.lang.Object

org.conqat.lib.commons.system.PerformanceMonitor

public class PerformanceMonitor
extends java.lang.Object

Combines a timer and a memory monitor in a simple utility class. Measures both total memory and the delta between start() and stop().

In order to avoid programming mistakes, the calls to the methods start() and stop() must adhere to a simple protocol:
The PerformanceMonitor can be in on of the three states NOT_RUN, RUNNING, FINISHED.

start() May only be called in state NOT_RUN and stop() may only be called in state RUNNING.

All other calls to start() and stop() result in IllegalArgumentExceptions

Author:

Elmar Juergens

Constructor Summary

Constructors

Constructor and Description
PerformanceMonitor(boolean useMemoryMonitor) Constructor has package level to allow tests to access it, yet enforce use of factory methods for public use.

Method Summary

Modifier and Type	Method and Description
static PerformanceMonitor	create() Convenience factory method: Creates a new PerformanceMonitor and starts it.
static PerformanceMonitor	create(boolean useMemoryMonitor) Convenience factory method: Creates a new PerformanceMonitor and starts it.
long	getDeltaMemUsageInBytes() Gets the delta in memory consumption in bytes
long	getDeltaMemUsageInKBs() Gets the delta in memory consumption in kilobytes
long	getMaxMemUsageInBytes() Gets the maximal memory consumption in bytes
long	getMaxMemUsageInKBs() Gets the maximal memory consumption in kilobytes
long	getMilliseconds() Gets the measured time in milliseconds.
long	getSeconds() Gets the measured time in seconds.
boolean	isStopped() Returns whether the PerformanceMonitor is stopped and will return meaningful values.
void	start() Starts the PerformanceMonitor.
long	stop() Stops the PerformanceMonitor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PerformanceMonitor

public PerformanceMonitor(boolean useMemoryMonitor)

Constructor has package level to allow tests to access it, yet enforce use of factory methods for public use.

Method Detail

create

public static PerformanceMonitor create(boolean useMemoryMonitor)

Convenience factory method: Creates a new PerformanceMonitor and starts it.

Parameters:

useMemoryMonitor - detemines whether the PerformanceMonitor internally uses a MemoryMonitor to measure memory consumption. This requires more resources, since the MemoryMonitor runs its own thread, but promises more precise measurement of maximum memory consumption.

create

public static PerformanceMonitor create()

Convenience factory method: Creates a new PerformanceMonitor and starts it. PerformanceMonitor does not use a MemoryMonitor internally

start

public void start()

Starts the PerformanceMonitor. It will measure time and maximal memory consumption until the method stop() is called.

This method may only be called, if the PerformanceMonitor is in state NOT_RUN. (i.e., after it has been created via the constructor). Node: the create() method creates and starts the monitor.

All subsequent calls to this method will result in a IllegalStateException

stop

public long stop()

Stops the PerformanceMonitor.

This method may only be called, if the PerformanceMonitor is in state RUNNING. (i.e., after a call to start() ).

If the PerformanceMonitor is in any other state, a call to this method results in an IllegalStateException

Returns:

The elapsed time in milliseconds.

isStopped

public boolean isStopped()

Returns whether the PerformanceMonitor is stopped and will return meaningful values.

getSeconds

public long getSeconds()

Gets the measured time in seconds. (Fractions of seconds are discarded)

getMilliseconds

public long getMilliseconds()

Gets the measured time in milliseconds. If measuring is not stopped, returns the time since start of the measuring.

getMaxMemUsageInBytes

public long getMaxMemUsageInBytes()

Gets the maximal memory consumption in bytes

getMaxMemUsageInKBs

public long getMaxMemUsageInKBs()

Gets the maximal memory consumption in kilobytes

getDeltaMemUsageInBytes

public long getDeltaMemUsageInBytes()

Gets the delta in memory consumption in bytes

getDeltaMemUsageInKBs

public long getDeltaMemUsageInKBs()

Gets the delta in memory consumption in kilobytes