public class SoftReference<T> extends Reference<T>
Suppose that the garbage collector determines at a certain point in time that an object is softly reachable. At that time it may choose to clear atomically all soft references to that object and all soft references to any other softly-reachable objects from which that object is reachable through a chain of strong references. At the same time or at some later time it will enqueue those newly-cleared soft references that are registered with reference queues.
All soft references to softly-reachable objects are guaranteed to have
been cleared before the virtual machine throws an
OutOfMemoryError
. Otherwise no constraints are placed upon the
time at which a soft reference will be cleared or the order in which a set
of such references to different objects will be cleared. Virtual machine
implementations are, however, encouraged to bias against clearing
recently-created or recently-used soft references.
The lack of information on the value to your application of each reference limits the usefulness of soft references. References that are cleared too early cause unnecessary work; those that are cleared too late waste memory.
Most applications should use an android.util.LruCache
instead of
soft references. LruCache has an effective eviction policy and lets the user
tune how much memory is allotted.
Constructor and Description |
---|
SoftReference(T referent)
Creates a new soft reference that refers to the given object.
|
SoftReference(T referent,
ReferenceQueue<? super T> q)
Creates a new soft reference that refers to the given object and is
registered with the given queue.
|
Modifier and Type | Method and Description |
---|---|
T |
get()
Returns this reference object's referent.
|
clear, enqueue, isEnqueued
public SoftReference(T referent)
referent
- object the new soft reference will refer topublic SoftReference(T referent, ReferenceQueue<? super T> q)
referent
- object the new soft reference will refer toq
- the queue with which the reference is to be registered,
or null if registration is not requiredpublic T get()
null
.