org.apache.openjpa.datacache
Class DelegatingDataCache

java.lang.Object
  org.apache.openjpa.datacache.DelegatingDataCache

All Implemented Interfaces:

DataCache, Closeable

public class DelegatingDataCache
extends Object
implements DataCache

Delegating data cache that can also perform exception translation for use in facades. This cache allows its delegate to be null, in which case it returns default values for all operations.

Author:

Abe White

Field Summary

Fields inherited from interface org.apache.openjpa.datacache.DataCache

NAME_DEFAULT

Constructor Summary

DelegatingDataCache(DataCache cache)
Constructor.

DelegatingDataCache(DataCache cache, RuntimeExceptionTranslator trans)

Method Summary

void	addExpirationListener(ExpirationListener listen) Add a new expiration event listener to this cache.
void	clear() Remove all data from this cache.
void	close() Free the resources used by this cache.
void	commit(Collection additions, Collection newUpdates, Collection existingUpdates, Collection deletes) Perform a batch update of the cache.
boolean	contains(Object oid) Returns true if this cache contains data corresponding to oid; otherwise returns false.
BitSet	containsAll(Collection oids) Returns the indexes of the oids in this cache.
boolean	equals(Object other)
DataCachePCData	get(Object oid) Return the cached object for the given oid.
DataCache	getDelegate() Return the direct delegate.
DataCache	getInnermostDelegate() Return the native delegate.
String	getName() Returns a string name that can be used by end-user-visible code to identify this cache.
int	hashCode()
void	initialize(DataCacheManager manager) Initialize any resources associated with the given DataCacheManager.
boolean	pin(Object oid) Pin the value stored under oid into the cache.
void	pinAll(Class cls, boolean subs) Pin all oids for the given type.
BitSet	pinAll(Collection oids) Pin all oids to the cache.
DataCachePCData	put(DataCachePCData value) Set the cached value for the given instance.
DataCachePCData	remove(Object oid) Remove the value stored under the given oid.
void	removeAll(Class cls, boolean subclasses) Evict all values of a specified type.
BitSet	removeAll(Collection oids) Remove the values stored under the given oids.
boolean	removeExpirationListener(ExpirationListener listen) Remove an expiration event listener from this cache.
void	setName(String name) Sets a string name to be used to identify this cache to end-user needs.
protected RuntimeException	translate(RuntimeException re) Translate the OpenJPA exception.
boolean	unpin(Object oid) Unpin the value stored under oid from the cache.
void	unpinAll(Class cls, boolean subs) Unpin all oids associaed with the given type from the cache.
BitSet	unpinAll(Collection oids) Unpin all oids from the cache.
void	update(DataCachePCData value) Update the cached value for the given instance.
void	writeLock() Obtain a write lock on the cache.
void	writeUnlock() Release the write lock on the cache.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DelegatingDataCache

public DelegatingDataCache(DataCache cache)

Constructor. Supply delegate.

DelegatingDataCache

public DelegatingDataCache(DataCache cache,
                           RuntimeExceptionTranslator trans)

Method Detail

getDelegate

public DataCache getDelegate()

Return the direct delegate.

getInnermostDelegate

public DataCache getInnermostDelegate()

Return the native delegate.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

translate

protected RuntimeException translate(RuntimeException re)

Translate the OpenJPA exception.

getName

public String getName()

Description copied from interface: DataCache

Returns a string name that can be used by end-user-visible code to identify this cache.

Specified by:

getName in interface DataCache

setName

public void setName(String name)

Description copied from interface: DataCache

Sets a string name to be used to identify this cache to end-user needs.

Specified by:

setName in interface DataCache

initialize

public void initialize(DataCacheManager manager)

Description copied from interface: DataCache

Initialize any resources associated with the given DataCacheManager.

Specified by:

initialize in interface DataCache

commit

public void commit(Collection additions,
                   Collection newUpdates,
                   Collection existingUpdates,
                   Collection deletes)

Description copied from interface: DataCache

Perform a batch update of the cache. Add all DataCachePCData objects in additions and in newUpdates, make the appropriate modifications to all DataCachePCDatas in existingUpdates, and delete all OIDs in deletes. All changes made to cached data must be made via this method. It is this method that is responsible for performing any side-effects that should happen on meaningful cache changes. Implementations should bear in mind that the deletes collection may contain oids that are also in the additions map. This is possible because it is valid for a user to delete an object with a particular oid and then add that object in the same batch.

Specified by:

commit in interface DataCache

Parameters:

additions - A collection of DataCachePCData objects. These represent data that have been newly created, and thus must be added to the cache.

newUpdates - A collection of DataCachePCData objects. These represent data that have been modified but were not originally in the cache, and thus must be added to the cache.

existingUpdates - A collection of DataCachePCData objects. These represent data that have been modified and were originally loaded from the cache. It is up to the cache implementation to decide if these values must be re-enlisted in the cache. Some caches may return live data from DataCache.get(java.lang.Object) invocations, in which case these values need not be re-enlisted.

deletes - A collection of object IDs that have been deleted and must therefore be dropped from the cache.

contains

public boolean contains(Object oid)

Description copied from interface: DataCache

Returns true if this cache contains data corresponding to oid; otherwise returns false.

Specified by:

contains in interface DataCache

containsAll

public BitSet containsAll(Collection oids)

Description copied from interface: DataCache

Returns the indexes of the oids in this cache.

Specified by:

containsAll in interface DataCache

get

public DataCachePCData get(Object oid)

Description copied from interface: DataCache

Return the cached object for the given oid. Modifying the returned object may or may not change the cached value; the DataCache.update(org.apache.openjpa.datacache.DataCachePCData) method should be used to re-cache any changed objects.

Specified by:

get in interface DataCache

Returns:

the object matching the given oid, or null if none

put

public DataCachePCData put(DataCachePCData value)

Description copied from interface: DataCache

Set the cached value for the given instance. This does not result in an update of other caches. Rather, it should only be used for loading clean data into the cache. Meaningful changes to the state of the cache should be made via the DataCache.commit(java.util.Collection, java.util.Collection, java.util.Collection, java.util.Collection) method.

Specified by:

put in interface DataCache

Returns:

The previously cached value, or null if the value was not previously cached. See Map.put(K, V) for more information.

update

public void update(DataCachePCData value)

Description copied from interface: DataCache

Update the cached value for the given instance. This does not result in an update of other caches. Rather, it should only be used for loading clean data into the cache. Meaningful changes to the state of the cache should be made via the DataCache.commit(java.util.Collection, java.util.Collection, java.util.Collection, java.util.Collection) method. A cache implementation may or may not return a live object from DataCache.get(java.lang.Object) invocations. If an object retrieved from a DataCache.get(java.lang.Object) operation needs to be updated, this method can be invoked instead of invoking DataCache.put(org.apache.openjpa.datacache.DataCachePCData). The DataCache implementation can then make optimizations based on how its DataCache.get(java.lang.Object) method works.

Specified by:

update in interface DataCache

remove

public DataCachePCData remove(Object oid)

Description copied from interface: DataCache

Remove the value stored under the given oid. This does not result in an update of other caches. Rather, it should only be used for removing data in the cache. Meaningful changes to the state of the cache should be made via the DataCache.commit(java.util.Collection, java.util.Collection, java.util.Collection, java.util.Collection) method.

Specified by:

remove in interface DataCache

Returns:

The previously cached value, or null if the oid was not previously cached. See Map.remove(java.lang.Object) for more information.

removeAll

public BitSet removeAll(Collection oids)

Description copied from interface: DataCache

Remove the values stored under the given oids.

Specified by:

removeAll in interface DataCache

Returns:

the indexes of the removed oids

See Also:

DataCache.remove(java.lang.Object)

removeAll

public void removeAll(Class cls,
                      boolean subclasses)

Description copied from interface: DataCache

Evict all values of a specified type.

Specified by:

removeAll in interface DataCache

clear

public void clear()

Description copied from interface: DataCache

Remove all data from this cache. This does not result in an update of other caches. Rather, it should only be used for clearing the cache. Meaningful changes to the state of the cache should be made via the DataCache.commit(java.util.Collection, java.util.Collection, java.util.Collection, java.util.Collection) method.

Specified by:

clear in interface DataCache

pin

public boolean pin(Object oid)

Description copied from interface: DataCache

Pin the value stored under oid into the cache. This method guarantees that oid's value will not be dropped by the caching algorithm. This method does not affect the behavior of DataCache.remove(java.lang.Object).

Specified by:

pin in interface DataCache

Returns:

true if oid's value was pinned into the cache; false if the oid is not in the cache.

pinAll

public BitSet pinAll(Collection oids)

Description copied from interface: DataCache

Pin all oids to the cache.

Specified by:

pinAll in interface DataCache

Returns:

the indexes of the pinned oids

See Also:

DataCache.pin(java.lang.Object)

pinAll

public void pinAll(Class cls,
                   boolean subs)

Description copied from interface: DataCache

Pin all oids for the given type.

Specified by:

pinAll in interface DataCache

subs - Whether to include subclasses.

unpin

public boolean unpin(Object oid)

Description copied from interface: DataCache

Unpin the value stored under oid from the cache. This method reverses a previous invocation of DataCache.pin(java.lang.Object). This method does not remove anything from the cache; it merely makes oid's value a candidate for flushing from the cache.

Specified by:

unpin in interface DataCache

Returns:

true if oid's value was unpinned from the cache; false if the oid is not in the cache.

unpinAll

public BitSet unpinAll(Collection oids)

Description copied from interface: DataCache

Unpin all oids from the cache.

Specified by:

unpinAll in interface DataCache

Returns:

the indexes of the unpinned oids

See Also:

DataCache.unpin(java.lang.Object)

unpinAll

public void unpinAll(Class cls,
                     boolean subs)

Description copied from interface: DataCache

Unpin all oids associaed with the given type from the cache.

Specified by:

unpinAll in interface DataCache

subs - Whether to include subclasses.

writeLock

public void writeLock()

Description copied from interface: DataCache

Obtain a write lock on the cache.

Specified by:

writeLock in interface DataCache

writeUnlock

public void writeUnlock()

Description copied from interface: DataCache

Release the write lock on the cache.

Specified by:

writeUnlock in interface DataCache

addExpirationListener

public void addExpirationListener(ExpirationListener listen)

Description copied from interface: DataCache

Add a new expiration event listener to this cache.

Specified by:

addExpirationListener in interface DataCache

removeExpirationListener

public boolean removeExpirationListener(ExpirationListener listen)

Description copied from interface: DataCache

Remove an expiration event listener from this cache.

Specified by:

removeExpirationListener in interface DataCache

close

public void close()

Description copied from interface: DataCache

Free the resources used by this cache.

Specified by:

close in interface DataCache

Specified by:

close in interface Closeable