Class MemorySailStore

java.lang.Object

org.eclipse.rdf4j.sail.memory.MemorySailStore

All Implemented Interfaces:

AutoCloseable, SailClosable, SailStore

class MemorySailStore
extends Object
implements SailStore

An implementation of SailStore that keeps committed statements in a MemStatementList.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private final class	MemorySailStore.MemorySailDataset
private final class	MemorySailStore.MemorySailSink
private final class	MemorySailStore.MemorySailSource
(package private) static class	MemorySailStore.SnapshotMonitor	SnapshotMonitor is used to keep track of which snapshot version are no longer is use (read or write) so that we can safely clean that snapshot version.

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	CLEANUP_MAX_MEMORY_THRESHOLD
private static final int	CLEANUP_MINIMUM_FREE_MEMORY
private static final double	CLEANUP_MINIMUM_FREE_MEMORY_RATIO
private int	currentSnapshot	Identifies the current snapshot.
static final MemResource[]	EMPTY_CONTEXT
static final EmptyIteration<MemStatement, SailException>	EMPTY_ITERATION
static final EmptyIteration<MemTriple, SailException>	EMPTY_TRIPLE_ITERATION
private final MemStatementIteratorCache	iteratorCache
private static final org.slf4j.Logger	logger
private static final long	MAX_MEMORY
private boolean	mayHaveInferred	This gets set to `true` when we add our first inferred statement.
private final MemNamespaceStore	namespaceStore	Store for namespace prefix info.
static final MemResource[]	NULL_CONTEXT
private static final Runtime	RUNTIME
private Thread	snapshotCleanupThread	Cleanup thread that removes deprecated statements when no other threads are accessing this list.
private final Object	snapshotCleanupThreadLockObject	Lock object used to synchronize concurrent access to snapshotCleanupThread.
(package private) final MemorySailStore.SnapshotMonitor	snapshotMonitor
private final MemStatementList	statements	List containing all available statements.
private final ExclusiveReentrantLockManager	txnLockManager	Lock manager used to prevent concurrent writes.
private final MemValueFactory	valueFactory	Factory/cache for MemValue objects.

Constructor Summary

Constructors

Constructor	Description
MemorySailStore(boolean debug)

Method Summary

Modifier and Type	Method	Description
protected void	cleanSnapshots()	Removes statements from old snapshots from the main statement list and resets the snapshot to 1 for the rest of the statements.
void	close()	Closes this resource, relinquishing any underlying resources.
private SailException	convertToSailException(InterruptedException e)
private CloseableIteration<MemStatement, SailException>	createStatementIterator(Resource subj, IRI pred, Value obj, Boolean explicit, int snapshot, Resource... contexts)	Creates a StatementIterator that contains the statements matching the specified pattern of subject, predicate, object, context.
private CloseableIteration<MemTriple, SailException>	createTripleIterator(Resource subj, IRI pred, Value obj, int snapshot)	Creates a TripleIterator that contains the triples matching the specified pattern of subject, predicate, object, context.
EvaluationStatistics	getEvaluationStatistics()	Used by SailSourceConnection to determine query join order.
SailSource	getExplicitSailSource()
private long	getFreeToAllocateMemory()
SailSource	getInferredSailSource()
private CloseableIteration<MemStatement, SailException>	getMemStatementIterator(MemResource subj, MemIRI pred, MemValue obj, Boolean explicit, int snapshot, MemResource[] memContexts, MemStatementList statementList)
private MemStatementList	getSmallestStatementList(MemResource subj, MemIRI pred, MemValue obj)
ValueFactory	getValueFactory()	The ValueFactory that should be used in association with this.
private void	invalidateCache()
private static boolean	memoryIsLow(long freeToAllocateMemory)
private boolean	prioritiseSnapshotCleaningIfLowOnMemory(boolean prioritiseCleaning)
protected void	scheduleSnapshotCleanup()

Methods inherited from class Object

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

Field Details

logger

private static final org.slf4j.Logger logger

RUNTIME

private static final Runtime RUNTIME

MAX_MEMORY

private static final long MAX_MEMORY

CLEANUP_MAX_MEMORY_THRESHOLD

private static final int CLEANUP_MAX_MEMORY_THRESHOLD

See Also:

• Constant Field Values

CLEANUP_MINIMUM_FREE_MEMORY

private static final int CLEANUP_MINIMUM_FREE_MEMORY

See Also:

• Constant Field Values

CLEANUP_MINIMUM_FREE_MEMORY_RATIO

private static final double CLEANUP_MINIMUM_FREE_MEMORY_RATIO

See Also:

• Constant Field Values

EMPTY_ITERATION

public static final EmptyIteration<MemStatement, SailException> EMPTY_ITERATION

EMPTY_TRIPLE_ITERATION

public static final EmptyIteration<MemTriple, SailException> EMPTY_TRIPLE_ITERATION

EMPTY_CONTEXT

public static final MemResource[] EMPTY_CONTEXT

NULL_CONTEXT

public static final MemResource[] NULL_CONTEXT

iteratorCache

private final MemStatementIteratorCache iteratorCache

valueFactory

private final MemValueFactory valueFactory

Factory/cache for MemValue objects.

statements

private final MemStatementList statements

List containing all available statements.

mayHaveInferred

private volatile boolean mayHaveInferred

This gets set to `true` when we add our first inferred statement. If the value is `false` we guarantee that there are no inferred statements in the MemorySailStore. If it is `true` then an inferred statement was added at some point, but we make no guarantees regarding if there still are inferred statements or if they are in the current snapshot.

The purpose of this variable is to optimize read operations that only read inferred statements when there are no inferred statements.

currentSnapshot

private volatile int currentSnapshot

Identifies the current snapshot.

snapshotMonitor

final MemorySailStore.SnapshotMonitor snapshotMonitor

namespaceStore

private final MemNamespaceStore namespaceStore

Store for namespace prefix info.

txnLockManager

private final ExclusiveReentrantLockManager txnLockManager

Lock manager used to prevent concurrent writes.

snapshotCleanupThread

private volatile Thread snapshotCleanupThread

Cleanup thread that removes deprecated statements when no other threads are accessing this list. Seee scheduleSnapshotCleanup().

snapshotCleanupThreadLockObject

private final Object snapshotCleanupThreadLockObject

Lock object used to synchronize concurrent access to snapshotCleanupThread.

Constructor Details

MemorySailStore

public MemorySailStore(boolean debug)

Method Details

getValueFactory

public ValueFactory getValueFactory()

Description copied from interface: SailStore

The ValueFactory that should be used in association with this.

Specified by:

getValueFactory in interface SailStore

Returns:

this object's ValueFactory

close

public void close()

Description copied from interface: SailClosable

Closes this resource, relinquishing any underlying resources.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface SailClosable

invalidateCache

private void invalidateCache()

getEvaluationStatistics

public EvaluationStatistics getEvaluationStatistics()

Description copied from interface: SailStore

Used by SailSourceConnection to determine query join order.

Specified by:

getEvaluationStatistics in interface SailStore

Returns:

a EvaluationStatistics that is aware of the data distribution of this SailStore .

getExplicitSailSource

public SailSource getExplicitSailSource()

Specified by:

getExplicitSailSource in interface SailStore

Returns:

SailSource of only explicit statements

getInferredSailSource

public SailSource getInferredSailSource()

Specified by:

getInferredSailSource in interface SailStore

Returns:

SailSource of only inferred statements

createStatementIterator

private CloseableIteration<MemStatement, SailException> createStatementIterator(Resource subj,
 IRI pred,
 Value obj,
 Boolean explicit,
 int snapshot,
 Resource... contexts)
                                                                         throws InterruptedException

Creates a StatementIterator that contains the statements matching the specified pattern of subject, predicate, object, context. Inferred statements are excluded when explicitOnly is set to true . Statements from the null context are excluded when namedContextsOnly is set to true. The returned StatementIterator will assume the specified read mode.

Throws:

InterruptedException

getMemStatementIterator

private CloseableIteration<MemStatement, SailException> getMemStatementIterator(MemResource subj,
 MemIRI pred,
 MemValue obj,
 Boolean explicit,
 int snapshot,
 MemResource[] memContexts,
 MemStatementList statementList)
                                                                         throws InterruptedException

Throws:

InterruptedException

getSmallestStatementList

private MemStatementList getSmallestStatementList(MemResource subj,
 MemIRI pred,
 MemValue obj)

createTripleIterator

private CloseableIteration<MemTriple, SailException> createTripleIterator(Resource subj,
 IRI pred,
 Value obj,
 int snapshot)
                                                                   throws InterruptedException

Creates a TripleIterator that contains the triples matching the specified pattern of subject, predicate, object, context.

Throws:

InterruptedException

cleanSnapshots

protected void cleanSnapshots()
                       throws InterruptedException

Removes statements from old snapshots from the main statement list and resets the snapshot to 1 for the rest of the statements.

Throws:

InterruptedException

prioritiseSnapshotCleaningIfLowOnMemory

private boolean prioritiseSnapshotCleaningIfLowOnMemory(boolean prioritiseCleaning)

memoryIsLow

private static boolean memoryIsLow(long freeToAllocateMemory)

getFreeToAllocateMemory

private long getFreeToAllocateMemory()

scheduleSnapshotCleanup

protected void scheduleSnapshotCleanup()

convertToSailException

private SailException convertToSailException(InterruptedException e)