Class FederationAccessManagerWithPersistedDiskCache

java.lang.Object

se.liu.ida.hefquin.engine.federation.access.impl.FederationAccessManagerWithCache

se.liu.ida.hefquin.engine.federation.access.impl.FederationAccessManagerWithPersistedDiskCache

All Implemented Interfaces:

StatsProvider, FederationAccessManager

public class FederationAccessManagerWithPersistedDiskCache
extends FederationAccessManagerWithCache

A FederationAccessManager implementation that incorporates persistent disk caching of SPARQL cardinality requests. TODO: The implementation uses a simple serialization/deserialization strategy, where the file is stored to disk by writing the full map to disk for each update. This approach is not optimized for this task but is simply intended as a proof of concept. A future implementation should support standard cache configuration policys, such as time-based eviction (time to live), but should leverage an optimized persistence strategy, preferably leveraging a libary. Note: Most of the classes/interfaces involved (e.g., DataRetrievalResponse, CardinalityResponse etc.) do not support serialization.

Nested Class Summary

Nested classes/interfaces inherited from class se.liu.ida.hefquin.engine.federation.access.impl.FederationAccessManagerWithCache

FederationAccessManagerWithCache.Key, FederationAccessManagerWithCache.MyDefaultCachePolicies

Field Summary

Fields

Modifier and Type	Field	Description
protected final PersistableCardinalityCacheImpl<CardinalityCacheKey>	cardinalityCache

Fields inherited from class se.liu.ida.hefquin.engine.federation.access.impl.FederationAccessManagerWithCache

cache, cacheHitsBRTPF, cacheHitsBRTPFCardinality, cacheHitsNeo4j, cacheHitsSPARQL, cacheHitsSPARQLCardinality, cacheHitsTPF, cacheHitsTPFCardinality, cacheMap, cacheRequestsBRTPF, cacheRequestsNeo4j, cacheRequestsSPARQL, cacheRequestsTPF, fedAccMan

Constructor Summary

Constructors

Constructor	Description
FederationAccessManagerWithPersistedDiskCache(ExecutorService execService)	Creates a FederationAccessManagerWithPersistedDiskCache with a default configuration.
FederationAccessManagerWithPersistedDiskCache(FederationAccessManager fedAccMan, int cacheCapacity)
FederationAccessManagerWithPersistedDiskCache(FederationAccessManager fedAccMan, int cacheCapacity, CachePolicies<FederationAccessManagerWithCache.Key,CompletableFuture<? extends DataRetrievalResponse<?>>,? extends CacheEntry<CompletableFuture<? extends DataRetrievalResponse<?>>>> cachePolicies)

Method Summary

Modifier and Type	Method	Description
void	clearCardinalityCache()	Clears the persisted cardinality cache map.
CompletableFuture<CardinalityResponse>	issueCardinalityRequest(BRTPFRequest req, BRTPFServer fm)
CompletableFuture<CardinalityResponse>	issueCardinalityRequest(SPARQLRequest req, SPARQLEndpoint fm)	Requests the cardinality of the result of the given request.
CompletableFuture<CardinalityResponse>	issueCardinalityRequest(TPFRequest req, BRTPFServer fm)
CompletableFuture<CardinalityResponse>	issueCardinalityRequest(TPFRequest req, TPFServer fm)

Methods inherited from class se.liu.ida.hefquin.engine.federation.access.impl.FederationAccessManagerWithCache

getStats, issueRequest, issueRequest, issueRequest, issueRequest, issueRequest, resetStats, shutdown

Methods inherited from class java.lang.Object

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

Field Details

cardinalityCache

protected final PersistableCardinalityCacheImpl<CardinalityCacheKey> cardinalityCache

Constructor Details

FederationAccessManagerWithPersistedDiskCache

public FederationAccessManagerWithPersistedDiskCache(FederationAccessManager fedAccMan,
 int cacheCapacity,
 CachePolicies<FederationAccessManagerWithCache.Key,CompletableFuture<? extends DataRetrievalResponse<?>>,? extends CacheEntry<CompletableFuture<? extends DataRetrievalResponse<?>>>> cachePolicies)

FederationAccessManagerWithPersistedDiskCache

public FederationAccessManagerWithPersistedDiskCache(FederationAccessManager fedAccMan,
 int cacheCapacity)

FederationAccessManagerWithPersistedDiskCache

public FederationAccessManagerWithPersistedDiskCache(ExecutorService execService)

Creates a FederationAccessManagerWithPersistedDiskCache with a default configuration.

Method Details

issueCardinalityRequest

public CompletableFuture<CardinalityResponse> issueCardinalityRequest(SPARQLRequest req,
 SPARQLEndpoint fm)
                                                               throws FederationAccessException

Description copied from interface: FederationAccessManager

Requests the cardinality of the result of the given request. Assumes that the given request contains a SPARQLGraphPattern rather than a full SPARQLQuery. If it does not, then this method throws an IllegalArgumentException.

Specified by:

issueCardinalityRequest in interface FederationAccessManager

Overrides:

issueCardinalityRequest in class FederationAccessManagerWithCache

Throws:

FederationAccessException

issueCardinalityRequest

public CompletableFuture<CardinalityResponse> issueCardinalityRequest(TPFRequest req,
 TPFServer fm)
                                                               throws FederationAccessException

Specified by:

issueCardinalityRequest in interface FederationAccessManager

Overrides:

issueCardinalityRequest in class FederationAccessManagerWithCache

Throws:

FederationAccessException

issueCardinalityRequest

public CompletableFuture<CardinalityResponse> issueCardinalityRequest(TPFRequest req,
 BRTPFServer fm)
                                                               throws FederationAccessException

Specified by:

issueCardinalityRequest in interface FederationAccessManager

Overrides:

issueCardinalityRequest in class FederationAccessManagerWithCache

Throws:

FederationAccessException

issueCardinalityRequest

public CompletableFuture<CardinalityResponse> issueCardinalityRequest(BRTPFRequest req,
 BRTPFServer fm)
                                                               throws FederationAccessException

Specified by:

issueCardinalityRequest in interface FederationAccessManager

Overrides:

issueCardinalityRequest in class FederationAccessManagerWithCache

Throws:

FederationAccessException

clearCardinalityCache

public void clearCardinalityCache()

Clears the persisted cardinality cache map.