com.sun.jini.collection

Class WeakKeyReference

java.lang.Object

java.lang.ref.Reference<T>

java.lang.ref.WeakReference

com.sun.jini.collection.WeakKeyReference

public class WeakKeyReference
extends WeakReference

A weak reference to a key in a table. Its hash code is that of its key at the time of the reference's creation. Its equals method will compare itself to another WeakKeyReference, or to another object that is then compared to the key held by this reference.

This class is public so that it can be used in other tables for which WeakTable won't work.

Author:

Sun Microsystems, Inc.

Field Summary

Fields

Modifier and Type	Field and Description
private static PrintStream	DEBUG Print debug messages to this stream if not null.
private int	hashCode The key's hashcode, set at creation.

Constructor Summary

Constructors

Constructor and Description
WeakKeyReference(Object key) Create a new WeakReference to the given key.
WeakKeyReference(Object key, ReferenceQueue refQueue) Create a new WeakReference to the given key, placing the cleared reference on the specified ReferenceQueue.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object other) Equivalence for WeakKeyReference is defined as follows: If the other reference is to this object, return true.
int	hashCode() Return the key's hashCode remembered from the time of reference creation.

Methods inherited from class java.lang.ref.Reference

clear, enqueue, get, isEnqueued

Methods inherited from class java.lang.Object

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

Field Detail

hashCode

private final int hashCode

The key's hashcode, set at creation.

DEBUG

private static final PrintStream DEBUG

Print debug messages to this stream if not null.

Constructor Detail

WeakKeyReference

public WeakKeyReference(Object key)

Create a new WeakReference to the given key. The reference is placed on no queue.

WeakKeyReference

public WeakKeyReference(Object key,
                ReferenceQueue refQueue)

Create a new WeakReference to the given key, placing the cleared reference on the specified ReferenceQueue.

Method Detail

hashCode

public int hashCode()

Return the key's hashCode remembered from the time of reference creation. If you intend to insert the key in a table after changing the key in a way that affects the hashCode, you will need to create a new WeakKeyReference for that new table.

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Equivalence for WeakKeyReference is defined as follows:

• If the other reference is to this object, return true.
• If this object's key is cleared, return false.
• If the other reference is to a WeakKeyReference object, return false if the other's key is cleared; otherwise return the result of invoking equals on the two keys.

Overrides:

equals in class Object