Skip navigation links
com.tangosol.util
Class AbstractKeyBasedMap.DeferredCacheEvent
java.lang.Object
java.util.EventObject
com.tangosol.util.MapEvent
com.tangosol.net.cache.CacheEvent
com.tangosol.util.AbstractKeyBasedMap.DeferredCacheEvent
- All Implemented Interfaces:
- java.io.Serializable
- Enclosing class:
- AbstractKeyBasedMap
-
protected abstract static class AbstractKeyBasedMap.DeferredCacheEvent
- extends CacheEvent
A DeferredCacheEvent is a CacheEvent
object that defers the loading of the old value
.
This event has two predominant states; active and inactive. The event is active from incarnation and can transition to inactive (via deactivate()
) but not vice-versa. Being active allows the getOldValue implementation to load the value from underlying map, thus all consumers of this event must ensure they call getOldValue prior to returning control when this event is dispatched.
Once inactive the correct value may no longer be available in the map thus in this state a getOldValue will return either null or the cached old value.
Field Summary |
protected boolean |
m_fActive
Whether the DeferredCacheEvent is in an active or inactive state. |
Fields inherited from class java.util.EventObject |
source |
Method Summary |
void |
deactivate()
Deactivate this DeferredCacheEvent instance. |
java.lang.Object |
getOldValue()
Return an old value associated with this event. |
protected abstract java.lang.Object |
readOldValue()
Perform a deferred read for the old value in a usage-specific way. |
Methods inherited from class com.tangosol.util.MapEvent |
dispatch, dispatch, dispatch, getDescription, getId, getKey, getMap, getNewEntry, getNewValue, getOldEntry, toString |
Methods inherited from class java.util.EventObject |
getSource |
m_fActive
protected volatile boolean m_fActive
- Whether the DeferredCacheEvent is in an active or inactive state.
AbstractKeyBasedMap.DeferredCacheEvent
public AbstractKeyBasedMap.DeferredCacheEvent(ObservableMap map,
int nId,
java.lang.Object oKey,
java.lang.Object oValueOld,
java.lang.Object oValueNew,
boolean fSynthetic)
- Constructs a new DeferredCacheEvent.
- Parameters:
nId
- this event's id, one of MapEvent.ENTRY_INSERTED
, MapEvent.ENTRY_UPDATED
or MapEvent.ENTRY_DELETED
oKey
- the key into the map
oValueOld
- the old value (for update and delete events)
oValueNew
- the new value (for insert and update events)
fSynthetic
- true iff the event is caused by the cache internal processing such as eviction or loading
getOldValue
public java.lang.Object getOldValue()
- Return an old value associated with this event.
The old value represents a value deleted from or updated in a map. It is always null for "insert" notifications.
-
- Overrides:
getOldValue
in class MapEvent
-
- Returns:
- an old value
readOldValue
protected abstract java.lang.Object readOldValue()
- Perform a deferred read for the old value in a usage-specific way.
deactivate
public void deactivate()
- Deactivate this DeferredCacheEvent instance. This is used to prevent future
getOldValue()
calls using the underlying map *after* the event dispatching code returned and the content of the map had been changed to a new value.
The contract between the DeferredCacheEvent and consumers of the event states that consumers must call getOldValue
prior to returning from event dispatching logic.
Skip navigation links
Copyright © 2000, 2014, Oracle and/or its affiliates. All rights reserved.