org.apache.openjpa.datacache
Class DelegatingDataCache

java.lang.Object
  extended by 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


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