org.apache.openjpa.datacache
Class ConcurrentDataCache

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


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