net.sf.ehcache.event
Class CacheEventListenerAdapter

java.lang.Object
  net.sf.ehcache.event.CacheEventListenerAdapter

All Implemented Interfaces:

Cloneable, CacheEventListener

public class CacheEventListenerAdapter
extends Object
implements CacheEventListener

An adapter to simplify cache event listeners that do not need all events defined on the CacheEventListener interface.

Author:

Ludovic Orban

Constructor Summary

CacheEventListenerAdapter()

Method Summary

Object	clone() Creates a clone of this listener.
void	dispose() Give the listener a chance to cleanup and free resources when no longer needed
void	notifyElementEvicted(Ehcache cache, Element element) Called immediately after an element is evicted from the cache.
void	notifyElementExpired(Ehcache cache, Element element) Called immediately after an element is found to be expired.
void	notifyElementPut(Ehcache cache, Element element) Called immediately after an element has been put into the cache.
void	notifyElementRemoved(Ehcache cache, Element element) Called immediately after an attempt to remove an element.
void	notifyElementUpdated(Ehcache cache, Element element) Called immediately after an element has been put into the cache and the element already existed in the cache.
void	notifyRemoveAll(Ehcache cache) Called during Ehcache.removeAll() to indicate that the all elements have been removed from the cache in a bulk operation.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CacheEventListenerAdapter

public CacheEventListenerAdapter()

Method Detail

clone

public Object clone()
             throws CloneNotSupportedException

Creates a clone of this listener. This method will only be called by ehcache before a cache is initialized.

This may not be possible for listeners after they have been initialized. Implementations should throw CloneNotSupportedException if they do not support clone.

Specified by:

clone in interface CacheEventListener

Overrides:

clone in class Object

Returns:

a clone

Throws:

CloneNotSupportedException - if the listener could not be cloned.

notifyElementRemoved

public void notifyElementRemoved(Ehcache cache,
                                 Element element)
                          throws CacheException

Called immediately after an attempt to remove an element. The remove method will block until this method returns.

This notification is received regardless of whether the cache had an element matching the removal key or not. If an element was removed, the element is passed to this method, otherwise a synthetic element, with only the key set is passed in.

This notification is not called for the following special cases:

1. removeAll was called. See CacheEventListener.notifyRemoveAll(net.sf.ehcache.Ehcache)
2. An element was evicted from the cache. See CacheEventListener.notifyElementEvicted(net.sf.ehcache.Ehcache, net.sf.ehcache.Element)

Specified by:

notifyElementRemoved in interface CacheEventListener

Parameters:

cache - the cache emitting the notification

element - the element just deleted, or a synthetic element with just the key set if no element was removed.

Throws:

CacheException

notifyElementPut

public void notifyElementPut(Ehcache cache,
                             Element element)
                      throws CacheException

Called immediately after an element has been put into the cache. The Cache.put(net.sf.ehcache.Element) method will block until this method returns.

Implementers may wish to have access to the Element's fields, including value, so the element is provided. Implementers should be careful not to modify the element. The effect of any modifications is undefined.

Specified by:

notifyElementPut in interface CacheEventListener

Parameters:

cache - the cache emitting the notification

element - the element which was just put into the cache.

Throws:

CacheException

notifyElementUpdated

public void notifyElementUpdated(Ehcache cache,
                                 Element element)
                          throws CacheException

Called immediately after an element has been put into the cache and the element already existed in the cache. This is thus an update.

The Cache.put(net.sf.ehcache.Element) method will block until this method returns.

Implementers may wish to have access to the Element's fields, including value, so the element is provided. Implementers should be careful not to modify the element. The effect of any modifications is undefined.

Specified by:

notifyElementUpdated in interface CacheEventListener

Parameters:

cache - the cache emitting the notification

element - the element which was just put into the cache.

Throws:

CacheException

notifyElementExpired

public void notifyElementExpired(Ehcache cache,
                                 Element element)

Called immediately after an element is found to be expired. The Cache.remove(Object) method will block until this method returns.

Elements are checked for expiry in ehcache at the following times:

• When a get request is made
• When an element is spooled to the diskStore in accordance with a MemoryStore eviction policy
• In the DiskStore when the expiry thread runs, which by default is Cache.DEFAULT_EXPIRY_THREAD_INTERVAL_SECONDS

If an element is found to be expired, it is deleted and this method is notified.

Specified by:

notifyElementExpired in interface CacheEventListener

Parameters:

cache - the cache emitting the notification

element - the element that has just expired

Deadlock Warning: expiry will often come from the DiskStore expiry thread. It holds a lock to the DiskStorea the time the notification is sent. If the implementation of this method calls into a synchronized Cache method and that subsequently calls into DiskStore a deadlock will result. Accordingly implementers of this method should not call back into Cache.

notifyElementEvicted

public void notifyElementEvicted(Ehcache cache,
                                 Element element)

Called immediately after an element is evicted from the cache. Evicted in this sense means evicted from one store and not moved to another, so that it exists nowhere in the local cache.

In a sense the Element has been removed from the cache, but it is different, thus the separate notification.

Specified by:

notifyElementEvicted in interface CacheEventListener

Parameters:

cache - the cache emitting the notification

element - the element that has just been evicted

notifyRemoveAll

public void notifyRemoveAll(Ehcache cache)

Called during Ehcache.removeAll() to indicate that the all elements have been removed from the cache in a bulk operation. The usual CacheEventListener.notifyElementRemoved(net.sf.ehcache.Ehcache, net.sf.ehcache.Element) is not called.

This notification exists because clearing a cache is a special case. It is often not practical to serially process notifications where potentially millions of elements have been bulk deleted.

Specified by:

notifyRemoveAll in interface CacheEventListener

Parameters:

cache - the cache emitting the notification

dispose

public void dispose()

Give the listener a chance to cleanup and free resources when no longer needed

Specified by:

dispose in interface CacheEventListener