cern::util::testhelpers::GarbageCollectionTestHelper Class Reference

Collaboration diagram for cern::util::testhelpers::GarbageCollectionTestHelper:

Public Member Functions
	GarbageCollectionTestHelper (Object refToSurveil)
boolean	waitForGC ()
boolean	waitForGC (long maxTimeout)
boolean	complexWaitForGC (long maxTimeout)
void	cancel ()
Private Attributes
Reference	ref
ReferenceQueue	refQ
volatile boolean	cancelFlag = false
volatile Thread	waitingThread
Static Private Attributes
static final long	GC_SLICE_MILLIS = 200

Detailed Description

A helper class to check if Garbage Collection works properly. It allows you to check whether an object is freed by the Garbage Collector.

To check whether an object is garbage collected, create an instance of this class and pass it the reference the object in to be surveilled for GC. Then, call the method waitForGC() to wait until the object is garbage collected. Here is sample code:


      Object obj = new Object();
      GarbageCollectionTestHelper gch = new GarbageCollectionTestHelper(obj);

          obj = null; // enable garbage collection

          if (gch.waitForGC(maxTimeoutMillis)) {
              System.out.println("garbage collection ok");
          } else {
              System.err.println("garbage collection problem");
          }

You have to use one instance of this class per reference you want to surveil.

This implementation isbased on the java.lang.ref.* classes. It keeps a PhantomReference to the reference and waits until the instance has been garbage collected.