org.mmbase.cache
Class QueryResultCache

java.lang.Object
  org.mmbase.cache.Cache<SearchQuery,List<MMObjectNode>>
      org.mmbase.cache.QueryResultCache

All Implemented Interfaces:

Map<SearchQuery,List<MMObjectNode>>, CacheMBean, EventListener, NodeEventListener, RelationEventListener, SizeMeasurable

Direct Known Subclasses:

AggregatedResultCache, MultilevelCache, NodeListCache, RelatedNodesCache

public abstract class QueryResultCache
extends Cache<SearchQuery,List<MMObjectNode>>
implements NodeEventListener, RelationEventListener

This cache provides a base implementation to cache the result of SearchQuery's. Such a cache links a SearchQuery object to a list of MMObjectNodes. A cache entry is automaticly invalidated if arbitrary node of one of the types present in the SearchQuery is changed (,created or deleted). This mechanism is not very subtle but it is garanteed to be correct. It means though that your cache can be considerably less effective for queries containing node types from which often nodes are edited.

Since:

MMBase-1.7

Version:

$Id: QueryResultCache.java 37235 2009-07-23 20:01:34Z michiel $

Author:

Daniel Ockeloen, Michiel Meeuwissen, Ernst Bunders

See Also:

SearchQuery

To Do:

Perhaps we could put the 'typeCounter' stuff in a sub-class.

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

Fields inherited from class org.mmbase.cache.Cache

lock, maxEntrySize

Constructor Summary

QueryResultCache(int size)

Method Summary

void	addReleaseStrategies(List<ReleaseStrategy> strategies)
void	addReleaseStrategy(ReleaseStrategy releaseStrategy) This method lets you add a release strategy to the cache.
void	clear()
double	getAvarageValueLength() Returns the average 'length' of the values in the cache.
ChainedReleaseStrategy	getReleaseStrategy()
protected int	nodeChanged(Event event)
void	notify(NodeEvent event)
void	notify(RelationEvent event)
List<MMObjectNode>	put(SearchQuery query, List<MMObjectNode> queryResult) Puts a search result in this cache.
List<MMObjectNode>	remove(Object key) Removes an object from the cache.
String	toString()

Methods inherited from class org.mmbase.cache.Cache

checkCachePolicy, contains, containsKey, containsValue, entrySet, equals, get, getByteSize, getByteSize, getCheapByteSize, getCount, getDefaultMaxEntrySize, getDescription, getHits, getImplementation, getLock, getMaxEntrySize, getMaxSize, getMisses, getName, getPuts, getRatio, getSize, getStats, hashCode, isActive, isEmpty, keySet, maxSize, putAll, putCache, reset, setActive, setImplementation, setMaxEntrySize, setMaxSize, size, values

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

QueryResultCache

public QueryResultCache(int size)

Method Detail

addReleaseStrategies

public void addReleaseStrategies(List<ReleaseStrategy> strategies)

Parameters:

strategies -

addReleaseStrategy

public void addReleaseStrategy(ReleaseStrategy releaseStrategy)

This method lets you add a release strategy to the cache. It will in fact be added to ChainedReleaseStrategy, which is the default base release strategy.

Parameters:

releaseStrategy - A releaseStrategy to add.

getReleaseStrategy

public ChainedReleaseStrategy getReleaseStrategy()

Returns:

Returns the releaseStrategy.

put

public List<MMObjectNode> put(SearchQuery query,
                              List<MMObjectNode> queryResult)

Puts a search result in this cache.

Specified by:

put in interface Map<SearchQuery,List<MMObjectNode>>

Overrides:

put in class Cache<SearchQuery,List<MMObjectNode>>

remove

public List<MMObjectNode> remove(Object key)

Removes an object from the cache. It alsos remove the watch from the observers which are watching this entry.

Specified by:

remove in interface Map<SearchQuery,List<MMObjectNode>>

Overrides:

remove in class Cache<SearchQuery,List<MMObjectNode>>

Parameters:

key - A SearchQuery object.

See Also:

Map.remove(java.lang.Object)

getAvarageValueLength

public double getAvarageValueLength()

Description copied from class: Cache

Returns the average 'length' of the values in the cache. Whatever that may mean. For a QueryResultCache the length obviously is the length of the cached lists. May return NaN if unknown or undetermined.

Specified by:

getAvarageValueLength in interface CacheMBean

Overrides:

getAvarageValueLength in class Cache<SearchQuery,List<MMObjectNode>>

toString

public String toString()

Overrides:

toString in class Cache<SearchQuery,List<MMObjectNode>>

notify

public void notify(RelationEvent event)

Specified by:

notify in interface RelationEventListener

See Also:

RelationEventListener.notify(org.mmbase.core.event.RelationEvent)

notify

public void notify(NodeEvent event)

Specified by:

notify in interface NodeEventListener

See Also:

NodeEventListener.notify(org.mmbase.core.event.NodeEvent)

nodeChanged

protected int nodeChanged(Event event)
                   throws IllegalArgumentException

Throws:

IllegalArgumentException

clear

public void clear()

Specified by:

clear in interface Map<SearchQuery,List<MMObjectNode>>

Specified by:

clear in interface CacheMBean

Overrides:

clear in class Cache<SearchQuery,List<MMObjectNode>>

See Also:

Map.clear()