org.apache.openjpa.datacache
Class AbstractQueryCache

java.lang.Object
  extended by org.apache.openjpa.lib.util.concurrent.AbstractConcurrentEventManager
      extended by org.apache.openjpa.datacache.AbstractQueryCache
All Implemented Interfaces:
Serializable, QueryCache, TypesChangedListener, Configurable, Closeable, EventManager
Direct Known Subclasses:
ConcurrentQueryCache

public abstract class AbstractQueryCache
extends AbstractConcurrentEventManager
implements QueryCache, Configurable

Abstract QueryCache implementation that provides various statistics, logging, and timeout functionality common across cache implementations.

Author:
Patrick Linskey, Abe White
See Also:
Serialized Form

Nested Class Summary
static class AbstractQueryCache.EvictPolicy
           
 
Field Summary
protected  OpenJPAConfiguration conf
          The configuration set by the system.
protected  ConcurrentHashMap<String,Long> entityTimestampMap
           
 AbstractQueryCache.EvictPolicy evictPolicy
           
protected  Log log
          The log to use.
 
Fields inherited from class org.apache.openjpa.lib.util.concurrent.AbstractConcurrentEventManager
_listeners
 
Constructor Summary
AbstractQueryCache()
           
 
Method Summary
 void addTypesChangedListener(TypesChangedListener listen)
          Add a new types event listener to this cache.
 void afterCommit(RemoteCommitEvent event)
          This method is part of the RemoteCommitListener interface.
 void clear()
          Remove all data from this cache.
protected abstract  void clearInternal()
          Clear the cache.
 void close()
          Free the resources used by this cache.
protected  void close(boolean clear)
           
 void endConfiguration()
          Invoked upon completion of bean property configuration for this object.
protected  void fireEvent(Object event, Object listener)
          Implement this method to fire the given event to the given listener.
 QueryResult get(QueryKey key)
          Return a list of oids for the given query key.
 List<Long> getAllEntityTimestamp(List<String> keyList)
          Returns a list of timestamps in the form of Long objects which are the last updated time stamps for the given entities in the keylist.
 AbstractQueryCache.EvictPolicy getEvictPolicy()
          Returns the evictionPolicy for QueryCache
protected abstract  QueryResult getInternal(QueryKey qk)
          Return the list for the given key.
 void initialize(DataCacheManager manager)
          Initialize any resources associated with the given DataCacheManager.
 boolean isClosed()
           
protected abstract  Collection keySet()
          Return a threadsafe view of the keys in this cache.
protected  Collection newListenerCollection()
          Individual query results will be registered as types changed listeners.
 void onTypesChanged(TypesChangedEvent ev)
          Notification that instances of persistent types have changed.
 boolean pin(QueryKey key)
          Pin the value stored under qk into the cache.
protected abstract  boolean pinInternal(QueryKey qk)
          Pin an object to the cache.
 QueryResult put(QueryKey qk, QueryResult oids)
          Set the list of OIDs for the given query key.
protected abstract  QueryResult putInternal(QueryKey qk, QueryResult oids)
          Add the given result to the cache, returning the old result under the given key.
 QueryResult remove(QueryKey key)
          Remove the value stored under the given query key.
protected  void removeAllInternal(Collection qks)
          Remove all results under the given keys from the cache.
protected abstract  QueryResult removeInternal(QueryKey qk)
          Remove the result under the given key from the cache.
 boolean removeTypesChangedListener(TypesChangedListener listen)
          Remove an types event listener from this cache.
 void setConfiguration(Configuration conf)
          Invoked prior to setting bean properties.
 void setEvictPolicy(String evictPolicy)
          Sets the eviction policy for the query cache
 void startConfiguration()
          Invoked before bean property configuration is begun on this object.
 boolean unpin(QueryKey key)
          Unpin the value stored under key into the cache.
protected abstract  boolean unpinInternal(QueryKey qk)
          Unpin an object from the cache.
protected  void updateEntityTimestamp(Map<String,Long> timestampMap)
          Updates the entity timestamp map with the current time in milliseconds
 
Methods inherited from class org.apache.openjpa.lib.util.concurrent.AbstractConcurrentEventManager
addListener, fireEvent, getListeners, hasListener, hasListeners, isFailFast, removeListener, setFailFast
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.openjpa.datacache.QueryCache
writeLock, writeUnlock
 

Field Detail

conf

protected OpenJPAConfiguration conf
The configuration set by the system.


log

protected Log log
The log to use.


entityTimestampMap

protected ConcurrentHashMap<String,Long> entityTimestampMap

evictPolicy

public AbstractQueryCache.EvictPolicy evictPolicy
Constructor Detail

AbstractQueryCache

public AbstractQueryCache()
Method Detail

initialize

public void initialize(DataCacheManager manager)
Description copied from interface: QueryCache
Initialize any resources associated with the given DataCacheManager.

Specified by:
initialize in interface QueryCache

onTypesChanged

public void onTypesChanged(TypesChangedEvent ev)
Description copied from interface: TypesChangedListener
Notification that instances of persistent types have changed.

Specified by:
onTypesChanged in interface TypesChangedListener

get

public QueryResult get(QueryKey key)
Description copied from interface: QueryCache
Return a list of oids for the given query key. This is an unmodifiable list.

Specified by:
get in interface QueryCache
Returns:
The query results matching the given key, or null if none

put

public QueryResult put(QueryKey qk,
                       QueryResult oids)
Description copied from interface: QueryCache
Set the list of OIDs for the given query key. A reference to the given list will be stored in the query cache, so the list should not be modified after invoking this method.

Specified by:
put in interface QueryCache
Returns:
The previously cached value, or null if the key was not previously cached. See Map.put(K, V) for more information.

remove

public QueryResult remove(QueryKey key)
Description copied from interface: QueryCache
Remove the value stored under the given query key. This method is typically not invoked directly from outside the QueryCache class. Instead, the cache should be updated by implementing RemoteCommitListener, which will result in all queries that may be invalid being dropped.

Specified by:
remove in interface QueryCache
Returns:
The previously cached value, or null if the key was not previously cached. See Map.remove(java.lang.Object) for more information.

pin

public boolean pin(QueryKey key)
Description copied from interface: QueryCache
Pin the value stored under qk into the cache. This method guarantees that qk's value will not be expired if the cache exceeds its capacity. It causes this data to be ignored when determining whether or not the cache is full, effectively increasing the total amount of data stored in the cache. This method does not affect the behavior of QueryCache.remove(org.apache.openjpa.datacache.QueryKey) or TypesChangedListener.onTypesChanged(org.apache.openjpa.datacache.TypesChangedEvent).

Specified by:
pin in interface QueryCache
Returns:
true if key's value was pinned into the cache; false if the key is not in the cache.

unpin

public boolean unpin(QueryKey key)
Description copied from interface: QueryCache
Unpin the value stored under key into the cache. This method reverses a previous invocation of QueryCache.pin(org.apache.openjpa.datacache.QueryKey). This method does not remove anything from the cache; it merely makes key's value a candidate for flushing from the cache.

Specified by:
unpin in interface QueryCache
Returns:
true if key's value was unpinned from the cache; false if the key is not in the cache.

clear

public void clear()
Description copied from interface: QueryCache
Remove all data from this cache.

Specified by:
clear in interface QueryCache

close

public void close()
Description copied from interface: QueryCache
Free the resources used by this cache.

Specified by:
close in interface QueryCache
Specified by:
close in interface Closeable

close

protected void close(boolean clear)

isClosed

public boolean isClosed()

addTypesChangedListener

public void addTypesChangedListener(TypesChangedListener listen)
Description copied from interface: QueryCache
Add a new types event listener to this cache.

Specified by:
addTypesChangedListener in interface QueryCache

removeTypesChangedListener

public boolean removeTypesChangedListener(TypesChangedListener listen)
Description copied from interface: QueryCache
Remove an types event listener from this cache.

Specified by:
removeTypesChangedListener in interface QueryCache

afterCommit

public void afterCommit(RemoteCommitEvent event)
This method is part of the RemoteCommitListener interface. If your cache subclass relies on OpenJPA for clustering support, make it implement RemoteCommitListener. This method will take care of invalidating entries from remote commits, by delegating to onTypesChanged(org.apache.openjpa.datacache.TypesChangedEvent).


keySet

protected abstract Collection keySet()
Return a threadsafe view of the keys in this cache. This collection must be iterable without risk of concurrent modification exceptions. It does not have to implement contains() efficiently or use set semantics.


getInternal

protected abstract QueryResult getInternal(QueryKey qk)
Return the list for the given key.


putInternal

protected abstract QueryResult putInternal(QueryKey qk,
                                           QueryResult oids)
Add the given result to the cache, returning the old result under the given key.


removeInternal

protected abstract QueryResult removeInternal(QueryKey qk)
Remove the result under the given key from the cache.


removeAllInternal

protected void removeAllInternal(Collection qks)
Remove all results under the given keys from the cache.


clearInternal

protected abstract void clearInternal()
Clear the cache.


pinInternal

protected abstract boolean pinInternal(QueryKey qk)
Pin an object to the cache.


unpinInternal

protected abstract boolean unpinInternal(QueryKey qk)
Unpin an object from the cache.


setConfiguration

public void setConfiguration(Configuration conf)
Description copied from interface: Configurable
Invoked prior to setting bean properties.

Specified by:
setConfiguration in interface Configurable

startConfiguration

public void startConfiguration()
Description copied from interface: Configurable
Invoked before bean property configuration is begun on this object.

Specified by:
startConfiguration in interface Configurable

endConfiguration

public void endConfiguration()
Description copied from interface: Configurable
Invoked upon completion of bean property configuration for this object.

Specified by:
endConfiguration in interface Configurable

fireEvent

protected void fireEvent(Object event,
                         Object listener)
Description copied from class: AbstractConcurrentEventManager
Implement this method to fire the given event to the given listener.

Specified by:
fireEvent in class AbstractConcurrentEventManager

newListenerCollection

protected Collection newListenerCollection()
Individual query results will be registered as types changed listeners. We want such query results to be gc'd once the only reference is held by the list of expiration listeners.

Overrides:
newListenerCollection in class AbstractConcurrentEventManager

setEvictPolicy

public void setEvictPolicy(String evictPolicy)
Sets the eviction policy for the query cache

Parameters:
evictPolicy - -- String value that specifies the eviction policy

getEvictPolicy

public AbstractQueryCache.EvictPolicy getEvictPolicy()
Returns the evictionPolicy for QueryCache

Returns:
-- returns a String value of evictPolicy attribute

updateEntityTimestamp

protected void updateEntityTimestamp(Map<String,Long> timestampMap)
Updates the entity timestamp map with the current time in milliseconds

Parameters:
timestampMap - -- a map that contains entityname and its last updated timestamp

getAllEntityTimestamp

public List<Long> getAllEntityTimestamp(List<String> keyList)
Returns a list of timestamps in the form of Long objects which are the last updated time stamps for the given entities in the keylist.

Parameters:
keyList - -- List of entity names
Returns:
-- Returns a list that has the timestamp for the given entities


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