kodo.datacache
Class QueryCacheImpl

java.lang.Object
  |
  +--kodo.datacache.QueryCacheImpl

All Implemented Interfaces:

ClassChangeListener, com.solarmetric.util.Closeable, Configurable, QueryCache

public class QueryCacheImpl

extends Object

implements QueryCache, Configurable, ClassChangeListener

Default query cache implementation.

Field Summary

protected Configuration

_conf

Constructor Summary

QueryCacheImpl()

Method Summary

void	classesChanged(Collection classes) Invoked when objects of the types in the classes set have been changed.
void	clear() Remove all data from this cache.
void	close() Close this cache, dropping all hard references and releasing any resources that this cache maintains.
void	endConfiguration() Invoked upon completion of bean property configuration for this object.
List	get(QueryKey qk) Return a list of OIDs for the given query key.
CacheMap	getCacheMap() Returns the underlying CacheMap that this QueryCacheImpl is using.
int	getCacheSize() Returns the maximum number of unpinned objects to keep hard references to.
QueryKeyExpirationListener	getExpirationListener() Returns this query cache's expiration listener.
int	getSoftReferenceSize() Returns the maximum number of unpinned objects to keep soft references to.
protected CacheMap	newCacheMap() Returns a new CacheMap for use as the underlying data cache.
void	notifyChangedClasses(Collection classes) Tells the cache that all the classes in the classes set have been changed.
boolean	pin(QueryKey qk) Pin the value stored under qk into the cache.
List	put(QueryKey qk, List oids) Set the list of OIDs for the given query key.
void	registerListener(ClassChangeListener ccl) Register ccl with this cache.
List	remove(QueryKey qk) Remove the value stored under the given query key.
void	removeListener(ClassChangeListener ccl) Unregister ccl from the set of listeners managed by this cache.
void	setCacheSize(int size) Sets the maximum number of unpinned objects to keep hard references to.
void	setConfiguration(Configuration conf) Invoked prior to setting bean properties.
void	setSoftReferenceSize(int size) Sets the maximum number of unpinned objects to keep soft references to.
void	startConfiguration() Invoked before bean property configuration is begun on this object.
boolean	unpin(QueryKey qk) Unpin the value stored under key into the cache.

Methods inherited from class java.lang.Object

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

Field Detail

_conf

protected Configuration _conf

Constructor Detail

QueryCacheImpl

public QueryCacheImpl()

Method Detail

getCacheMap

public CacheMap getCacheMap()

Returns the underlying CacheMap that this QueryCacheImpl is using. This is not an unmodifiable view on the map, so care should be taken with this reference. Implementations should probably not mess with the contents of the cache, but should only use this reference to obtain cache metrics. Additionally, this map may contain expired data. Removal of timed-out data is done in a lazy fashion, so the actual size of the map may be greater than the number of non-expired query results in cache.

Methods that manipulate the cache map should synchronize on the map.

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.

newCacheMap

protected CacheMap newCacheMap()

Returns a new CacheMap for use as the underlying data cache. This implementation returns a CacheMap. To implement a more sophisticated caching strategy, override this method to return a subclass of CacheMap.

notifyChangedClasses

public void notifyChangedClasses(Collection classes)

Description copied from interface: QueryCache

Tells the cache that all the classes in the classes set have been changed. This could mean that items have been updated, deleted, or added. This limits the QueryCache to only be able to invalidate cached queries -- because the cache is not notified of actual changes, it cannot recompute query results.

After this method is invoked, all cached results that correspond to queries that use one of the classes in classes will be dropped.

Specified by:

notifyChangedClasses in interface QueryCache

Following copied from interface: kodo.datacache.QueryCache

Parameters:

classes - a set of Class objects that correspond to instances that have changed

registerListener

public void registerListener(ClassChangeListener ccl)

Description copied from interface: QueryCache

Register ccl with this cache.

Specified by:

registerListener in interface QueryCache

removeListener

public void removeListener(ClassChangeListener ccl)

Description copied from interface: QueryCache

Unregister ccl from the set of listeners managed by this cache.

Specified by:

removeListener in interface QueryCache

classesChanged

public void classesChanged(Collection classes)

Description copied from interface: ClassChangeListener

Invoked when objects of the types in the classes set have been changed. This could mean that items have been updated, deleted, or added.

Specified by:

classesChanged in interface ClassChangeListener

Following copied from interface: kodo.datacache.ClassChangeListener

Parameters:

classes - a set of Class objects that correspond to instances that have changed

get

public List get(QueryKey qk)

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

Following copied from interface: kodo.datacache.QueryCache

Returns:

the query results matching the given key, or null if none.

put

public List put(QueryKey qk,
                List 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

Following copied from interface: kodo.datacache.QueryCache

Returns:

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

remove

public List remove(QueryKey qk)

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 invoking QueryCache.notifyChangedClasses(java.util.Collection), which will result in all queries that may be invalid being dropped.

Specified by:

remove in interface QueryCache

Following copied from interface: kodo.datacache.QueryCache

Returns:

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

clear

public void clear()

Description copied from interface: QueryCache

Remove all data from this cache.

Specified by:

clear in interface QueryCache

pin

public boolean pin(QueryKey qk)

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(kodo.datacache.QueryKey) or QueryCache.notifyChangedClasses(java.util.Collection).

Specified by:

pin in interface QueryCache

Following copied from interface: kodo.datacache.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 qk)

Description copied from interface: QueryCache

Unpin the value stored under key into the cache. This method reverses a previous invocation of QueryCache.pin(kodo.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

Following copied from interface: kodo.datacache.QueryCache

Returns:

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

close

public void close()

Description copied from interface: QueryCache

Close this cache, dropping all hard references and releasing any resources that this cache maintains.

Specified by:

close in interface QueryCache

getExpirationListener

public QueryKeyExpirationListener getExpirationListener()

Description copied from interface: QueryCache

Returns this query cache's expiration listener.

Specified by:

getExpirationListener in interface QueryCache

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