Package org.eclipse.rdf4j.sail.memory
Class MemoryStore
- java.lang.Object
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- org.eclipse.rdf4j.sail.helpers.AbstractSail
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- org.eclipse.rdf4j.sail.helpers.AbstractNotifyingSail
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- org.eclipse.rdf4j.sail.memory.MemoryStore
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- All Implemented Interfaces:
FederatedServiceResolverClient,NotifyingSail,Sail
public class MemoryStore extends AbstractNotifyingSail implements FederatedServiceResolverClient
An implementation of the Sail interface that stores its data in main memory and that can use a file for persistent storage. This Sail implementation supports single, isolated transactions. This means that changes to the data are not visible until a transaction is committed and that concurrent transactions are not possible. When another transaction is active, calls to startTransaction() will block until the active transaction is committed or rolled back.The MemoryStore is designed for datasets with fewer than 100,000 triples. The MemoryStore uses hash tables, and when these hash tables fill up it copies the values to larger hash tables. This can cause strain on the garbage collector due to lots of memory being allocated and freed.
- Author:
- Arjohn Kampman, jeen
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Field Summary
Fields Modifier and Type Field Description protected static StringDATA_FILE_NAMEprotected static StringSYNC_FILE_NAME-
Fields inherited from class org.eclipse.rdf4j.sail.helpers.AbstractSail
connectionTimeOut, DEFAULT_CONNECTION_TIMEOUT, DEFAULT_ITERATION_SYNC_THRESHOLD, initializationLock
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Constructor Summary
Constructors Constructor Description MemoryStore()Creates a new MemoryStore.MemoryStore(File dataDir)Creates a new persistent MemoryStore.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected voidcancelSyncTask()protected voidcancelSyncTimer()protected NotifyingSailConnectiongetConnectionInternal()Returns a store-specific SailConnection object.EvaluationStrategyFactorygetEvaluationStrategyFactory()FederatedServiceResolvergetFederatedServiceResolver()Gets theFederatedServiceResolverused by this client.booleangetPersist()longgetSyncDelay()Gets the currently configured sync delay.ValueFactorygetValueFactory()Gets a ValueFactory object that can be used to create IRI-, blank node-, literal- and statement objects.protected voidinitializeInternal()Initializes this repository.booleanisWritable()Checks whether this Sail object is writable.voidnotifySailChanged(SailChangedEvent event)Notifies all registered SailChangedListener's of changes to the contents of this Sail.protected voidscheduleSyncTask()voidsetEvaluationStrategyFactory(EvaluationStrategyFactory factory)Sets theEvaluationStrategyto use.voidsetFederatedServiceResolver(FederatedServiceResolver resolver)Overrides theFederatedServiceResolverused by this instance, but the given resolver is not shutDown when this instance is.voidsetPersist(boolean persist)voidsetSyncDelay(long syncDelay)Sets the time (in milliseconds) to wait after a transaction was commited before writing the changed data to file.protected voidshutDownInternal()Do store-specific operations to ensure proper shutdown of the store.voidsync()Synchronizes the contents of this repository with the data that is stored on disk.-
Methods inherited from class org.eclipse.rdf4j.sail.helpers.AbstractNotifyingSail
addSailChangedListener, getConnection, removeSailChangedListener
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Methods inherited from class org.eclipse.rdf4j.sail.helpers.AbstractSail
addSupportedIsolationLevel, connectionClosed, debugEnabled, getDataDir, getDefaultIsolationLevel, getDefaultQueryEvaluationMode, getIterationCacheSyncThreshold, getSupportedIsolationLevels, init, isInitialized, isTrackResultSize, removeSupportedIsolationLevel, setConnectionTimeOut, setDataDir, setDefaultIsolationLevel, setDefaultQueryEvaluationMode, setIterationCacheSyncThreshold, setSupportedIsolationLevels, setSupportedIsolationLevels, setTrackResultSize, shutDown, toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.eclipse.rdf4j.sail.Sail
getDataDir, getDefaultIsolationLevel, getSupportedIsolationLevels, init, setDataDir, shutDown
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Field Detail
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DATA_FILE_NAME
protected static final String DATA_FILE_NAME
- See Also:
- Constant Field Values
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SYNC_FILE_NAME
protected static final String SYNC_FILE_NAME
- See Also:
- Constant Field Values
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Constructor Detail
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MemoryStore
public MemoryStore()
Creates a new MemoryStore.
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MemoryStore
public MemoryStore(File dataDir)
Creates a new persistent MemoryStore. If the specified data directory contains an existing store, its contents will be restored upon initialization.- Parameters:
dataDir- the data directory to be used for persistence.
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Method Detail
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setPersist
public void setPersist(boolean persist)
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getPersist
public boolean getPersist()
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setSyncDelay
public void setSyncDelay(long syncDelay)
Sets the time (in milliseconds) to wait after a transaction was commited before writing the changed data to file. Setting this variable to 0 will force a file sync immediately after each commit. A negative value will deactivate file synchronization until the Sail is shut down. A positive value will postpone the synchronization for at least that amount of milliseconds. If in the meantime a new transaction is started, the file synchronization will be rescheduled to wait for another syncDelay ms. This way, bursts of transaction events can be combined in one file sync.The default value for this parameter is 0 (immediate synchronization).
- Parameters:
syncDelay- The sync delay in milliseconds.
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getSyncDelay
public long getSyncDelay()
Gets the currently configured sync delay.- Returns:
- syncDelay The sync delay in milliseconds.
- See Also:
setSyncDelay(long)
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getEvaluationStrategyFactory
public EvaluationStrategyFactory getEvaluationStrategyFactory()
- Returns:
- Returns the
EvaluationStrategy.
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setEvaluationStrategyFactory
public void setEvaluationStrategyFactory(EvaluationStrategyFactory factory)
Sets theEvaluationStrategyto use.
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getFederatedServiceResolver
public FederatedServiceResolver getFederatedServiceResolver()
Description copied from interface:FederatedServiceResolverClientGets theFederatedServiceResolverused by this client.- Specified by:
getFederatedServiceResolverin interfaceFederatedServiceResolverClient- Returns:
- Returns the SERVICE resolver.
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setFederatedServiceResolver
public void setFederatedServiceResolver(FederatedServiceResolver resolver)
Overrides theFederatedServiceResolverused by this instance, but the given resolver is not shutDown when this instance is.- Specified by:
setFederatedServiceResolverin interfaceFederatedServiceResolverClient- Parameters:
resolver- The SERVICE resolver to set.
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initializeInternal
protected void initializeInternal() throws SailExceptionInitializes this repository. If a persistence file is defined for the store, the contents will be restored.- Overrides:
initializeInternalin classAbstractSail- Throws:
SailException- when initialization of the store failed.
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shutDownInternal
protected void shutDownInternal() throws SailExceptionDescription copied from class:AbstractSailDo store-specific operations to ensure proper shutdown of the store.- Specified by:
shutDownInternalin classAbstractSail- Throws:
SailException
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isWritable
public boolean isWritable()
Checks whether this Sail object is writable. A MemoryStore is not writable if a read-only data file is used.- Specified by:
isWritablein interfaceSail
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getConnectionInternal
protected NotifyingSailConnection getConnectionInternal() throws SailException
Description copied from class:AbstractSailReturns a store-specific SailConnection object.- Specified by:
getConnectionInternalin classAbstractNotifyingSail- Returns:
- A connection to the store.
- Throws:
SailException
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getValueFactory
public ValueFactory getValueFactory()
Description copied from interface:SailGets a ValueFactory object that can be used to create IRI-, blank node-, literal- and statement objects.- Specified by:
getValueFactoryin interfaceSail- Returns:
- a ValueFactory object for this Sail object.
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notifySailChanged
public void notifySailChanged(SailChangedEvent event)
Description copied from class:AbstractNotifyingSailNotifies all registered SailChangedListener's of changes to the contents of this Sail.- Overrides:
notifySailChangedin classAbstractNotifyingSail
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scheduleSyncTask
protected void scheduleSyncTask() throws SailException- Throws:
SailException
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cancelSyncTask
protected void cancelSyncTask()
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cancelSyncTimer
protected void cancelSyncTimer()
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sync
public void sync() throws SailExceptionSynchronizes the contents of this repository with the data that is stored on disk. Data will only be written when the contents of the repository and data in the file are out of sync.- Throws:
SailException
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