mondrian.rolap.cache
Class MemorySegmentCache

java.lang.Object
  mondrian.rolap.cache.MemorySegmentCache

All Implemented Interfaces:

SegmentCache

public class MemorySegmentCache
extends Object
implements SegmentCache

Implementation of SegmentCache that stores segments in memory.

Segments are held via soft references, so the garbage collector can remove them if it sees fit.

Not thread safe.

Author:

Julian Hyde

Nested Class Summary

Nested classes/interfaces inherited from interface mondrian.spi.SegmentCache

SegmentCache.SegmentCacheInjector, SegmentCache.SegmentCacheListener

Constructor Summary

MemorySegmentCache()

Method Summary

void	addListener(SegmentCache.SegmentCacheListener listener) Adds a listener to this segment cache implementation.
boolean	contains(SegmentHeader header) Checks if the cache contains a SegmentBody corresponding to the supplied SegmentHeader.
void	fireSegmentCacheEvent(SegmentCache.SegmentCacheListener.SegmentCacheEvent evt)
SegmentBody	get(SegmentHeader header) Returns a SegmentBody once the cache has returned any results, or null if no segment corresponding to the header could be found.
List<SegmentHeader>	getSegmentHeaders() Returns a list of all segments present in the cache.
boolean	put(SegmentHeader header, SegmentBody body) Stores a segment data in the cache.
boolean	remove(SegmentHeader header) Removes a segment from the cache.
void	removeListener(SegmentCache.SegmentCacheListener listener) Unregisters a listener from this segment cache implementation.
boolean	supportsRichIndex() Tells Mondrian whether this segment cache uses the SegmentHeader objects as an index, thus preserving them in a serialized state, or if it uses its identification number only.
void	tearDown() Tear down and clean up the cache.

Methods inherited from class java.lang.Object

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

Constructor Detail

MemorySegmentCache

public MemorySegmentCache()

Method Detail

get

public SegmentBody get(SegmentHeader header)

Description copied from interface: SegmentCache

Returns a SegmentBody once the cache has returned any results, or null if no segment corresponding to the header could be found.

Cache implementations are at liberty to 'forget' segments. Therefore it is allowable for this method to return null at any time, even if SegmentCache.contains(SegmentHeader) for this segment previously returned true.

Specified by:

get in interface SegmentCache

Parameters:

header - The header of the segment to find. Consider this as a key.

Returns:

A SegmentBody, or null if no corresponding segment could be found in cache.

contains

public boolean contains(SegmentHeader header)

Description copied from interface: SegmentCache

Checks if the cache contains a SegmentBody corresponding to the supplied SegmentHeader.

Specified by:

contains in interface SegmentCache

Parameters:

header - A header to lookup in the cache.

Returns:

Whether corresponding segment could be found in cache.

getSegmentHeaders

public List<SegmentHeader> getSegmentHeaders()

Description copied from interface: SegmentCache

Returns a list of all segments present in the cache.

Specified by:

getSegmentHeaders in interface SegmentCache

Returns:

A List of segment headers describing the contents of the cache.

put

public boolean put(SegmentHeader header,
                   SegmentBody body)

Description copied from interface: SegmentCache

Stores a segment data in the cache.

Specified by:

put in interface SegmentCache

Parameters:

header - The header of the segment.

body - The segment body to cache.

Returns:

Whether the cache write succeeded

remove

public boolean remove(SegmentHeader header)

Description copied from interface: SegmentCache

Removes a segment from the cache.

Specified by:

remove in interface SegmentCache

Parameters:

header - The header of the segment we want to remove.

Returns:

True if the segment was found and removed, false otherwise.

tearDown

public void tearDown()

Description copied from interface: SegmentCache

Tear down and clean up the cache.

Specified by:

tearDown in interface SegmentCache

addListener

public void addListener(SegmentCache.SegmentCacheListener listener)

Description copied from interface: SegmentCache

Adds a listener to this segment cache implementation. The listener will get notified via SegmentCache.SegmentCacheListener.SegmentCacheEvent instances.

Specified by:

addListener in interface SegmentCache

Parameters:

listener - The listener to attach to this cache.

removeListener

public void removeListener(SegmentCache.SegmentCacheListener listener)

Description copied from interface: SegmentCache

Unregisters a listener from this segment cache implementation.

Specified by:

removeListener in interface SegmentCache

Parameters:

listener - The listener to remove.

supportsRichIndex

public boolean supportsRichIndex()

Description copied from interface: SegmentCache

Tells Mondrian whether this segment cache uses the SegmentHeader objects as an index, thus preserving them in a serialized state, or if it uses its identification number only.

Not using a rich index prevents Mondrian from doing partial cache invalidation.

It is assumed that this method returns fairly quickly, and for a given cache always returns the same value.

Specified by:

supportsRichIndex in interface SegmentCache

Returns:

Whether this segment cache preserves headers in serialized state

fireSegmentCacheEvent

public void fireSegmentCacheEvent(SegmentCache.SegmentCacheListener.SegmentCacheEvent evt)