org.springframework.util
Class WeakReferenceMonitor

java.lang.Object
  org.springframework.util.WeakReferenceMonitor

public class WeakReferenceMonitor
extends Object

Track references to arbitrary objects using proxy and weak references. To monitor a handle, one should call monitor(Object, ReleaseListener), with the given handle object usually being a holder that uses the target object underneath, and the release listener performing cleanup of the target object once the handle is not strongly referenced anymore.

When a given handle becomes weakly reachable, the specified listener will be called by a background thread. This thread will only be started lazily and will be stopped once no handles are registered for monitoring anymore, to be restarted if further handles are added.

Thanks to Tomasz Wysocki for the suggestion and the original implementation of this class!

Since:

1.2

Author:

Colin Sampaleanu, Juergen Hoeller

See Also:

monitor(java.lang.Object, org.springframework.util.WeakReferenceMonitor.ReleaseListener)

Nested Class Summary

static interface

WeakReferenceMonitor.ReleaseListener Listener that is notified when the handle is being released.

Constructor Summary

WeakReferenceMonitor()

Method Summary

static void

monitor(Object handle, WeakReferenceMonitor.ReleaseListener listener) Start to monitor given handle object for becoming weakly reachable.

Methods inherited from class java.lang.Object

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

Constructor Detail

WeakReferenceMonitor

public WeakReferenceMonitor()

Method Detail

monitor

public static void monitor(Object handle,
                           WeakReferenceMonitor.ReleaseListener listener)

Start to monitor given handle object for becoming weakly reachable. When the handle isn't used anymore, the given listener will be called.

Parameters:

handle - the object that will be monitored

listener - the listener that will be called upon release of the handle