jjbridge.engine.utils

Class ReferenceMonitor<T>

java.lang.Object

java.lang.Thread

jjbridge.engine.utils.ReferenceMonitor<T>

All Implemented Interfaces:

Runnable

public class ReferenceMonitor<T>
extends Thread

This class simplifies the interaction with the Java garbage collector, allowing a custom finalization action to be performed on an object before it is definitely cleared from the memory.

The usage is the following:

 // Initialize the monitor
 ReferenceMonitor<SomeType> monitor = new ReferenceMonitor<>();
 monitor.start();

 // Create your object as usual
 SomeType obj = new SomeType();

 // Allow the monitor to track `obj` lifecycle, specifying the action to be performed before garbage collection.
 monitor.track(obj, () -> {
     System.out.println("Performing clean up for `obj`");
 });

 // Once all references to `obj` are lost, the garbage collector will detect `obj` can be cleared, and the clean up
 // action will be performed.
 

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
ReferenceMonitor() Creates a reference monitor with default settings.
ReferenceMonitor(long millisPause) Creates a reference monitor.

Method Summary

Modifier and Type	Method and Description
protected void	clean(NativeReference<T> ref)
void	interrupt()
void	run()
void	track(T object, CleanUpAction cleanUpAction) Associate a clean up action to be performed by this monitor when the object is garbage collected.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Constructor Detail

ReferenceMonitor

public ReferenceMonitor()

Creates a reference monitor with default settings.

This is equivalent to calling ReferenceMonitor(long) with millisPause = 50

ReferenceMonitor

public ReferenceMonitor(long millisPause)

Creates a reference monitor.

Parameters:

millisPause - the number of milliseconds the reference monitor will pause its execution if there are no pending references to clear.

Method Detail

track

public void track(T object,
                  CleanUpAction cleanUpAction)

Associate a clean up action to be performed by this monitor when the object is garbage collected.

For the reference monitor to perform the clean up, it is important that the clean up action DOES NOT CONTAIN any reference to the tracked object.
Failing in this, the object will never be garbage collected, hence the reference monitor will never run the clean up action.

Parameters:

object - the object to track

cleanUpAction - the action to be performed

clean

protected void clean(NativeReference<T> ref)

run

public void run()

Specified by:

run in interface Runnable

Overrides:

run in class Thread

interrupt

public void interrupt()

Overrides:

interrupt in class Thread