public interface CacheListener<K,V> extends CacheCallback
A listener to handle region or entry related events.
Instead of implementing this interface it is recommended that you extend the
CacheListenerAdapter
class.
The methods on a CacheListener
are invoked while holding a lock on the entry
described by the EntryEvent
, as a result if the listener method takes a long time to
execute then it will cause the operation that caused it to be invoked to take a long time. In
addition, listener code which calls Region
methods could result in a deadlock. For
example, in afterUpdate(EntryEvent)
for entry key k1, put(k2, someVal)
is called at the same time afterUpdate(EntryEvent)
for entry key k2
calls put(k1, someVal)
a deadlock may result. This co-key
dependency example can be extended to a co-Region dependency where listener code in Region "A"
performs Region operations on "B" and listener code in Region "B" performs Region operations on
"A". Deadlocks may be either java-level or distributed multi-VM dead locks depending on Region
configuration. To be assured of no deadlocks, listener code should cause some other thread to
access the region and must not wait for that thread to complete the task.
WARNING: To avoid risk of deadlock, do not invoke CacheFactory.getAnyInstance() from within any callback methods. Instead use EntryEvent.getRegion().getCache() or RegionEvent.getRegion().getCache().
Multiple events, on different entries, can cause concurrent invocation of
CacheListener
methods. Any exceptions thrown by the listener are caught by GemFire
and logged.
To declare a CacheListener in a Cache XML file, it must also implement Declarable
AttributesFactory.addCacheListener(org.apache.geode.cache.CacheListener<K, V>)
,
AttributesFactory.initCacheListeners(org.apache.geode.cache.CacheListener<K, V>[])
,
RegionAttributes.getCacheListeners()
,
AttributesMutator.addCacheListener(org.apache.geode.cache.CacheListener<K, V>)
,
AttributesMutator.removeCacheListener(org.apache.geode.cache.CacheListener<K, V>)
,
AttributesMutator.initCacheListeners(org.apache.geode.cache.CacheListener<K, V>[])
Modifier and Type | Method and Description |
---|---|
void |
afterCreate(EntryEvent<K,V> event)
Handles the event of new key being added to a region.
|
void |
afterDestroy(EntryEvent<K,V> event)
Handles the event of an entry being destroyed.
|
void |
afterInvalidate(EntryEvent<K,V> event)
Handles the event of an entry's value being invalidated.
|
void |
afterRegionClear(RegionEvent<K,V> event)
Handles the event of a region being cleared.
|
void |
afterRegionCreate(RegionEvent<K,V> event)
Handles the event of a region being created.
|
void |
afterRegionDestroy(RegionEvent<K,V> event)
Handles the event of a region being destroyed.
|
void |
afterRegionInvalidate(RegionEvent<K,V> event)
Handles the event of a region being invalidated.
|
void |
afterRegionLive(RegionEvent<K,V> event)
Handles the event of a region being live after receiving the marker from the server.
|
void |
afterUpdate(EntryEvent<K,V> event)
Handles the event of an entry's value being modified in a region.
|
close
init, initialize
void afterCreate(EntryEvent<K,V> event)
event
- the EntryEventRegion.create(Object, Object)
,
Region.put(Object, Object)
,
Region.get(Object)
void afterUpdate(EntryEvent<K,V> event)
event
- the EntryEventRegion.put(Object, Object)
void afterInvalidate(EntryEvent<K,V> event)
event
- the EntryEventRegion.invalidate(Object)
void afterDestroy(EntryEvent<K,V> event)
event
- the EntryEventRegion.destroy(Object)
void afterRegionInvalidate(RegionEvent<K,V> event)
regionInvalidated
event invoked on its listener.event
- the RegionEventRegion.invalidateRegion()
,
Region.localInvalidateRegion()
void afterRegionDestroy(RegionEvent<K,V> event)
afterRegionDestroyed
event invoked on its listener.event
- the RegionEventRegion.destroyRegion()
,
Region.localDestroyRegion()
,
Region.close()
,
RegionService.close()
void afterRegionClear(RegionEvent<K,V> event)
event
- the RegionEventRegion.clear()
void afterRegionCreate(RegionEvent<K,V> event)
Note that this method is only called for creates done in the local vm. To be notified of
creates done in remote vms use RegionMembershipListener.afterRemoteRegionCreate(org.apache.geode.cache.RegionEvent<K, V>)
.
event
- the RegionEventCache.createRegion(java.lang.String, org.apache.geode.cache.RegionAttributes<K, V>)
,
Region.createSubregion(java.lang.String, org.apache.geode.cache.RegionAttributes<SK, SV>)
void afterRegionLive(RegionEvent<K,V> event)
event
- the RegionEventCache.readyForEvents()