com.sapportals.wcm.util.cache

Interface IClusterCacheArea

public interface IClusterCacheArea

Represents a cacheable area. A cacheable area is identified by its unique ID. An area is either in state valid or invalid. These states are toggled by the following events:

from		event	to	side-effect
VALID		validate()	VALID	initial state, calling validate() won't do anything.
VALID		invalidate()	VALID	calling invalidate() will send an INVALIDATE event and update the getLastNodeInvalidation() timestamp.
VALID		INVALIDATE	INVALID	an INVALIDATE event from other cluster nodes invalidates the cache area and updates the getLastClusterInvalidation() timestamp.
INVALID		INVALIDATE	INVALID	INVALIDATE event in INVALID state just update the getLastClusterInvalidation() timestamp.
INVALID		invalidate()	INVALID	calling invalidate() will send an INVALIDATE event and update the getLastNodeInvalidation() timestamp.
INVALID		validate()	VALID	calling validate() toogles the state back to VALID.

For example used by the IDMapper.

Method Summary

String	getAreaID() Get the area's ID.
long	getClusterTimeout() Get the cluster cache timeout.
long	getLastClusterInvalidation() Get the timestamp of the last (external) invalidation from other cluster nodes.
long	getLastInvalidation() Get the timestamp of the last invalidation (internally or externally, the later one).
long	getLastNodeInvalidation() Get the timestamp of the last (internal) invalidation from this node.
void	invalidate() Mark this cache area as invalid.
boolean	isCluster() Get the cluster's cache flag.
boolean	isValid() Check, if this cache area is marked as invalid.
void	refresh(ICache cache) Remove all expired entries from the given cache (does a cache.removeEntriesOlderThan(getLastClusterInvalidation())).
void	validate() Mark this cache area as valid.

Method Detail

getAreaID

public String getAreaID()

Get the area's ID.

Returns:

a String, which holds the area's ID.

isCluster

public boolean isCluster()

Get the cluster's cache flag.

Returns:

true if the system is running in cluster mode.

getClusterTimeout

public long getClusterTimeout()

Get the cluster cache timeout.

Returns:

a long with the system's cluster cache timeout in msec.

validate

public void validate()

Mark this cache area as valid. Changes the state from INVALID to VALID.

refresh

public void refresh(ICache cache)
             throws CacheException

Remove all expired entries from the given cache (does a cache.removeEntriesOlderThan(getLastClusterInvalidation())).

Parameters:

cache - the ICache to remove expired entries from.

Throws:

CacheException

invalidate

public void invalidate()

Mark this cache area as invalid. Sends an INVALIDATE event to the other cluster nodes but doesn't change the state.

isValid

public boolean isValid()

Check, if this cache area is marked as invalid.

Returns:

true, if state is VALID.

getLastInvalidation

public long getLastInvalidation()

Get the timestamp of the last invalidation (internally or externally, the later one).

Returns:

the timestamp of the last invalidation, the later timestamp from getLastExternalInvalidation() and getLastInternalInvalidation().

getLastClusterInvalidation

public long getLastClusterInvalidation()

Get the timestamp of the last (external) invalidation from other cluster nodes.

Returns:

a long with the timestamp of the last incoming INVALIDATE event.

getLastNodeInvalidation

public long getLastNodeInvalidation()

Get the timestamp of the last (internal) invalidation from this node.

Returns:

a long with the timestamp of the last call to invalidate().