[/url] [url=file:///F:/资料/文字资料/j2sdk-1_4_2-doc/docs/api/overview-summary.html]Overview
Class
JavaTM 2 Platform
Std. Ed. v1.4.2
SUMMARY: NESTED | FIELD | CONSTR | METHOD
DETAIL: FIELD | CONSTR | METHOD
java.lang.ref
Class Referencejava.lang.Object
Direct Known Subclasses: PhantomReference, SoftReference, WeakReference public abstract class Reference extends ObjectAbstract 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. 用于引用对象的抽象基类。该类定义了所有引用对象的公共操作。因为引用对象的实现 与垃圾收集器密切相关，所以该类不能被直接继承。
Since: 1.2 Method Summary
void
clear()
Clears this reference object. 清除引用对象。
boolean
enqueue()
Adds this reference object to the queue with which it is registered, if any. 如果存在该队列，则加入引用对象到其注册的队列中。
get()
Returns this reference object's referent. 返回引用对象的引用。
boolean
Tells whether or not this reference object has been enqueued, either by the program or by the garbage collector. 告知引用对象是否已被程序或垃圾收集器加入队列中。
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Method Detail
getpublic Object get()
Returns this reference object's referent. If this reference object has been cleared, either by the program or by the garbage collector, then this method returns null. 返回引用对象的引用。如果引用对象已被程序或垃圾收集器清除，则方法返回null。
Returns: The object to which this reference refers, or null if this reference object has been cleared 引用指向的对象，如果引用对象已被清除，返回nullclearpublic void clear()
Clears this reference object. Invoking this method will not cause this object to be enqueued. 清除引用对象。调用该方法不会将对象加入队列。
isEnqueuedpublic boolean isEnqueued()
Tells whether or not this reference object has been enqueued, either by the program or by the garbage collector. If this reference object was not registered with a queue when it was created, then this method will always return false. 告知引用对象是否已被程序或垃圾收集器加入队列中。如果引用对象在创建时没有被注册进队列， 那么方法将总是返回false。
Returns: true if and only if this reference object has been enqueued 只有引用对象已被加入队列才返回trueenqueuepublic boolean enqueue()
Adds this reference object to the queue with which it is registered, if any. 如果存在该队列，则加入引用对象到其注册的队列中。
Returns: 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 created 如果引用对象被成功加入队列，返回true；如果它已被加入队列或者在它创建时 没有被注册进队列，返回false[/url][url=file:///F:/资料/文字资料/j2sdk-1_4_2-doc/docs/api/overview-summary.html]Overview
Class
JavaTM 2 Platform
Std. Ed. v1.4.2
SUMMARY: NESTED | FIELD | CONSTR | METHOD
DETAIL: FIELD | CONSTR | METHOD
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
