WeakReferenceContainer (Castor JDO - Persistence framework 1.3.1 API)

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org.castor.cache.hashbelt.container
Class WeakReferenceContainer

java.lang.Object
  org.castor.cache.hashbelt.container.WeakReferenceContainer

All Implemented Interfaces:: Map<Object,Object>, Container

public final class WeakReferenceContainer
extends Object
implements Container
extends Object
implements Container

An implementation of a container that uses weak references for storing values in the map, so that values can be removed from the map by the system when the system is under memory pressure. Keys, however, are kept strong - so contains() may well find an element, but the value may have been lost. Make sure you test for null returns from put.

Note that keys are hard references; in a situation where OutOfMemory will occur, the JVM will first wipe out all unreferenced objects whose only link is a weak reference. An out of memory will wipe all values from the maps which are currently unreferenced. The keys remain until the hashbelt containers are garbage collected, an put is called with that key or when the value should be accessed through any operation of the Container interface.

Since:: 1.0
Version:: $Revision: 8102 $ $Date: 2006-04-25 16:09:10 -0600 (Tue, 25 Apr 2006) $
Author:: Gregory Block, Ralf Joachim

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map
`Map.Entry<K,V>`

Constructor Summary
`WeakReferenceContainer()`

Method Summary
`void`	`clear()`
`boolean`	`containsKey(Object key)`
`boolean`	`containsValue(Object value)`
`Set<Map.Entry<Object,Object>>`	`entrySet()`
`Object`	`get(Object key)`
`long`	`getTimestamp()` Returns the timestamp of this container.
`boolean`	`isEmpty()`
`Iterator<Object>`	`keyIterator()` Returns an iterator over the keys contained in this container.
`Set<Object>`	`keySet()`
`Object`	`put(Object key, Object value)`
`void`	`putAll(Map<? extends Object,? extends Object> map)`
`Object`	`remove(Object key)`
`int`	`size()`
`void`	`updateTimestamp()` Set the timestamp of this container to System.currentTimeMillis().
`Iterator<Object>`	`valueIterator()` Returns an iterator over the values contained in this container.
`Collection<Object>`	`values()`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Methods inherited from interface java.util.Map
`equals, hashCode`

Constructor Detail