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public abstract class Reference extends Object
Abstract base class for reference objects. This class defines the operations common to all reference objects. Because reference objects are implemented in close cooperation with the garbage collector, this class may not be subclassed directly.
Method Summary | |
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void |
clear() Clears this reference object. |
boolean |
enqueue() Adds this reference object to the queue with which it is registered, if any. |
Object |
get() Returns this reference object's referent. |
boolean |
Tells whether or not this reference object has been enqueued, either by the program or by the garbage collector. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Method Detail |
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public void clear()
This method is invoked only by Java code; when the garbage collector clears references it does so directly, without invoking this method.
public boolean enqueue()
This method is invoked only by Java code; when the garbage collector enqueues references it does so directly, without invoking this method.
true
if this reference object was successfully
enqueued; false
if it was already enqueued or if
it was not registered with a queue when it was createdpublic Object get()
null
.
null
if this reference object has been clearedpublic boolean isEnqueued()
false
.
true
if and only if this reference object has
been enqueued
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