java.lang.ref
Class WeakReference<T>
java.lang.Object
java.lang.ref.Reference<T>
java.lang.ref.WeakReference<T>
public class WeakReference<T>
- extends Reference<T>
A weak reference will be cleared, if the object is only weakly
reachable. It is useful for lookup tables, where you aren't
interested in an entry, if the key isn't reachable anymore.
WeakHashtable
is a complete implementation of such a
table.
It is also useful to make objects unique: You create a set of weak
references to those objects, and when you create a new object you
look in this set, if the object already exists and return it. If
an object is not referenced anymore, the reference will
automatically cleared, and you may remove it from the set.
- See Also:
WeakHashMap
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
WeakReference
public WeakReference(T referent)
- Create a new weak reference, that is not registered to any queue.
- Parameters:
referent
- the object we refer to.
WeakReference
public WeakReference(T referent,
ReferenceQueue<? super T> q)
- Create a new weak reference.
- Parameters:
referent
- the object we refer to.q
- the reference queue to register on.
- Throws:
NullPointerException
- if q is null.