org.apache.openjpa.datacache
Class ConcurrentDataCache

java.lang.Object
  org.apache.openjpa.lib.util.concurrent.AbstractConcurrentEventManager
      org.apache.openjpa.datacache.AbstractDataCache
          org.apache.openjpa.datacache.ConcurrentDataCache

All Implemented Interfaces:

DataCache, RemoteCommitListener, Configurable, Closeable, EventManager

public class ConcurrentDataCache
extends AbstractDataCache
implements RemoteCommitListener

A DataCache implementation that is optimized for concurrent access. When the cache fills up, values to remove from cache are chosen randomly. Due to race conditions, it is possible that a get call might not return a cached instance if that instance is being transferred between internal datastructures.

Since:

0.4.0

Field Summary

Fields inherited from class org.apache.openjpa.datacache.AbstractDataCache

conf, log

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

NAME_DEFAULT

Constructor Summary

ConcurrentDataCache()

Method Summary

protected void	clearInternal() Clear the cache.
CacheMap	getCacheMap() Returns the underlying CacheMap that this cache is using.
int	getCacheSize() Returns the maximum number of unpinned objects to keep hard references to.
protected DataCachePCData	getInternal(Object key) Return the object for the given oid.
int	getSoftReferenceSize() Returns the maximum number of unpinned objects to keep soft references to.
void	initialize(DataCacheManager mgr) Initialize any resources associated with the given DataCacheManager.
protected CacheMap	newCacheMap() Return the map to use as an internal cache; entry expirations must invoke AbstractDataCache.keyRemoved(java.lang.Object, boolean).
protected boolean	pinInternal(Object key) Pin an object to the cache.
protected DataCachePCData	putInternal(Object key, DataCachePCData pc) Add the given object to the cache, returning the old object under the given oid.
protected void	removeAllInternal(Class cls, boolean subs) Evict objects in cache by class.
protected DataCachePCData	removeInternal(Object key) Remove the object under the given oid from the cache.
void	setCacheSize(int size) Sets the maximum number of unpinned objects to keep hard references to.
void	setSoftReferenceSize(int size) Sets the maximum number of unpinned objects to keep soft references to.
void	unpinAll(Class cls, boolean subs) Unpin all oids associaed with the given type from the cache.
protected boolean	unpinInternal(Object key) Unpin an object from the cache.
void	writeLock() Obtain a write lock on the cache.
void	writeUnlock() Release the write lock on the cache.

Methods inherited from class org.apache.openjpa.datacache.AbstractDataCache

addExpirationListener, afterCommit, clear, close, close, commit, contains, containsAll, endConfiguration, fireEvent, get, getEvictionSchedule, getName, isClosed, keyRemoved, pin, pinAll, pinAll, put, putAllInternal, recacheUpdates, remove, removeAll, removeAll, removeAllInternal, removeAllTypeNamesInternal, removeExpirationListener, setConfiguration, setEvictionSchedule, setName, startConfiguration, toString, unpin, unpinAll, update

Methods inherited from class org.apache.openjpa.lib.util.concurrent.AbstractConcurrentEventManager

addListener, fireEvent, getListeners, hasListener, hasListeners, isFailFast, newListenerCollection, removeListener, setFailFast

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.openjpa.event.RemoteCommitListener

afterCommit, close

Constructor Detail

ConcurrentDataCache

public ConcurrentDataCache()

Method Detail

getCacheMap

public CacheMap getCacheMap()

Returns the underlying CacheMap that this cache is using. This is not an unmodifiable view on the map, so care should be taken with this reference. Implementations should probably not modify the contents of the cache, but should only use this reference to obtain cache metrics.

setCacheSize

public void setCacheSize(int size)

Sets the maximum number of unpinned objects to keep hard references to. If the map contains more unpinned objects than size, then this method will result in the cache flushing old values.

getCacheSize

public int getCacheSize()

Returns the maximum number of unpinned objects to keep hard references to.

setSoftReferenceSize

public void setSoftReferenceSize(int size)

Sets the maximum number of unpinned objects to keep soft references to. If the map contains more soft references than size, then this method will result in the cache flushing values.

getSoftReferenceSize

public int getSoftReferenceSize()

Returns the maximum number of unpinned objects to keep soft references to. Defaults to -1.

initialize

public void initialize(DataCacheManager mgr)

Description copied from interface: DataCache

Initialize any resources associated with the given DataCacheManager.

Specified by:

initialize in interface DataCache

Overrides:

initialize in class AbstractDataCache

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

Overrides:

unpinAll in class AbstractDataCache

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

newCacheMap

protected CacheMap newCacheMap()

Return the map to use as an internal cache; entry expirations must invoke AbstractDataCache.keyRemoved(java.lang.Object, boolean).

getInternal

protected DataCachePCData getInternal(Object key)

Description copied from class: AbstractDataCache

Return the object for the given oid.

Specified by:

getInternal in class AbstractDataCache

putInternal

protected DataCachePCData putInternal(Object key,
                                      DataCachePCData pc)

Description copied from class: AbstractDataCache

Add the given object to the cache, returning the old object under the given oid.

Specified by:

putInternal in class AbstractDataCache

removeInternal

protected DataCachePCData removeInternal(Object key)

Description copied from class: AbstractDataCache

Remove the object under the given oid from the cache.

Specified by:

removeInternal in class AbstractDataCache

removeAllInternal

protected void removeAllInternal(Class cls,
                                 boolean subs)

Description copied from class: AbstractDataCache

Evict objects in cache by class.

Specified by:

removeAllInternal in class AbstractDataCache

clearInternal

protected void clearInternal()

Description copied from class: AbstractDataCache

Clear the cache.

Specified by:

clearInternal in class AbstractDataCache

pinInternal

protected boolean pinInternal(Object key)

Description copied from class: AbstractDataCache

Pin an object to the cache.

Specified by:

pinInternal in class AbstractDataCache

unpinInternal

protected boolean unpinInternal(Object key)

Description copied from class: AbstractDataCache

Unpin an object from the cache.

Specified by:

unpinInternal in class AbstractDataCache