Package org.eclipse.rdf4j.federated

Class FedXConnection

java.lang.Object

org.eclipse.rdf4j.sail.helpers.AbstractSailConnection

org.eclipse.rdf4j.federated.FedXConnection

All Implemented Interfaces:

AutoCloseable, SailConnection

public class FedXConnection
extends AbstractSailConnection

An implementation of RepositoryConnection that uses FederationEvalStrategy to evaluate provided queries. Prior to evaluation various optimizations are performed, see FedXOptimizer for further details.

Since 4.0 FedX supports write operations using the supplied WriteStrategy, e.g. by writing to a designated federation member. Note: the WriteStrategy is initialized lazily upon first access to a write operation, see getWriteStrategyInternal(). Implementation notes: - not all methods are implemented as of now

Author:

Andreas Schwarte

See Also:

• FederationEvalStrategy
• WriteStrategy

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	FedXConnection.SailBaseDefaultImpl	A default implementation for AbstractSail.

Field Summary

Fields

Modifier and Type	Field	Description
protected final FedX	federation
protected final FederationContext	federationContext

Fields inherited from class org.eclipse.rdf4j.sail.helpers.AbstractSailConnection

connectionLock, updateLock

Constructor Summary

Constructors

Constructor	Description
FedXConnection(FedX federation, FederationContext federationContext)

Method Summary

Modifier and Type	Method	Description
protected void	addStatementInternal(Resource subj, IRI pred, Value obj, Resource... contexts)
protected void	clearInternal(Resource... contexts)
protected void	clearNamespacesInternal()
protected void	closeInternal()
protected void	commitInternal()
protected CloseableIteration<? extends BindingSet,QueryEvaluationException>	evaluateInternal(TupleExpr query, Dataset dataset, BindingSet bindings, boolean includeInferred)
Explanation	explain(Explanation.Level level, TupleExpr tupleExpr, Dataset dataset, BindingSet bindings, boolean includeInferred, int timeoutSeconds)	Explain how the TupleExpr will be (or has been) executed/evaluated by returning a TupleExpr (which may or may not be the provided TupleExpr) that has gone through zero or more of the stages prior to and also including execution as specified by the provided level.
protected CloseableIteration<? extends Resource,SailException>	getContextIDsInternal()
protected String	getNamespaceInternal(String prefix)
protected CloseableIteration<? extends Namespace,SailException>	getNamespacesInternal()
protected CloseableIteration<? extends Statement,SailException>	getStatementsInternal(Resource subj, IRI pred, Value obj, boolean includeInferred, Resource... contexts)
protected WriteStrategy	getWriteStrategyInternal()	Return the initialized writeStrategy.
boolean	pendingRemovals()	Indicates if the Sail has any statement removal operations pending (not yet flushed) for the current transaction.
protected void	removeNamespaceInternal(String prefix)
protected void	removeStatementsInternal(Resource subj, IRI pred, Value obj, Resource... contexts)
protected void	rollbackInternal()
protected void	setNamespaceInternal(String prefix, String name)
void	setTransactionSettings(TransactionSetting... settings)	Pass any transaction-specific settings to the SailConnection.
protected long	sizeInternal(Resource... contexts)
protected void	startTransactionInternal()

Methods inherited from class org.eclipse.rdf4j.sail.helpers.AbstractSailConnection

addStatement, addStatement, autoStartTransaction, begin, begin, clear, clearNamespaces, close, commit, endUpdate, endUpdateInternal, evaluate, flush, getContextIDs, getExclusiveConnectionLock, getNamespace, getNamespaces, getSharedConnectionLock, getStatements, getTransactionIsolation, getTransactionLock, isActive, isActiveOperation, isOpen, iterationClosed, pendingAdds, prepare, prepareInternal, registerIteration, removeNamespace, removeStatement, removeStatements, rollback, setNamespace, size, startUpdate, transactionActive, verifyIsActive, verifyIsOpen

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.rdf4j.sail.SailConnection

hasStatement, prepareQuery

Field Details

federation

protected final FedX federation

federationContext

protected final FederationContext federationContext

Constructor Details

FedXConnection

public FedXConnection(FedX federation,
 FederationContext federationContext)
               throws SailException

Throws:

SailException

Method Details

setTransactionSettings

public void setTransactionSettings(TransactionSetting... settings)

Description copied from interface: SailConnection

Pass any transaction-specific settings to the SailConnection. This method needs to be called before the transaction is started .

Sail implementations can override this method to receive the transaction settings (to inspect and/or pass them along to any wrapped sail objects). Remember to call super.setTransactionSettings(settings) if you override this method.

Parameters:

settings - the transaction settings on which the next transaction operates. It may or may not contain the isolation level.

evaluateInternal

protected CloseableIteration<? extends BindingSet,QueryEvaluationException> evaluateInternal(TupleExpr query,
 Dataset dataset,
 BindingSet bindings,
 boolean includeInferred)
                                                                                      throws SailException

Specified by:

evaluateInternal in class AbstractSailConnection

Throws:

SailException

clearInternal

protected void clearInternal(Resource... contexts)
                      throws SailException

Specified by:

clearInternal in class AbstractSailConnection

Throws:

SailException

clearNamespacesInternal

protected void clearNamespacesInternal()
                                throws SailException

Specified by:

clearNamespacesInternal in class AbstractSailConnection

Throws:

SailException

closeInternal

protected void closeInternal()
                      throws SailException

Specified by:

closeInternal in class AbstractSailConnection

Throws:

SailException

commitInternal

protected void commitInternal()
                       throws SailException

Specified by:

commitInternal in class AbstractSailConnection

Throws:

SailException

getContextIDsInternal

protected CloseableIteration<? extends Resource,SailException> getContextIDsInternal()
                                                                              throws SailException

Specified by:

getContextIDsInternal in class AbstractSailConnection

Throws:

SailException

getNamespaceInternal

protected String getNamespaceInternal(String prefix)
                               throws SailException

Specified by:

getNamespaceInternal in class AbstractSailConnection

Throws:

SailException

getNamespacesInternal

protected CloseableIteration<? extends Namespace,SailException> getNamespacesInternal()
                                                                               throws SailException

Specified by:

getNamespacesInternal in class AbstractSailConnection

Throws:

SailException

getStatementsInternal

protected CloseableIteration<? extends Statement,SailException> getStatementsInternal(Resource subj,
 IRI pred,
 Value obj,
 boolean includeInferred,
 Resource... contexts)
                                                                               throws SailException

Specified by:

getStatementsInternal in class AbstractSailConnection

Throws:

SailException

addStatementInternal

protected void addStatementInternal(Resource subj,
 IRI pred,
 Value obj,
 Resource... contexts)
                             throws SailException

Specified by:

addStatementInternal in class AbstractSailConnection

Throws:

SailException

removeNamespaceInternal

protected void removeNamespaceInternal(String prefix)
                                throws SailException

Specified by:

removeNamespaceInternal in class AbstractSailConnection

Throws:

SailException

removeStatementsInternal

protected void removeStatementsInternal(Resource subj,
 IRI pred,
 Value obj,
 Resource... contexts)
                                 throws SailException

Specified by:

removeStatementsInternal in class AbstractSailConnection

Throws:

SailException

rollbackInternal

protected void rollbackInternal()
                         throws SailException

Specified by:

rollbackInternal in class AbstractSailConnection

Throws:

SailException

setNamespaceInternal

protected void setNamespaceInternal(String prefix,
 String name)
                             throws SailException

Specified by:

setNamespaceInternal in class AbstractSailConnection

Throws:

SailException

sizeInternal

protected long sizeInternal(Resource... contexts)
                     throws SailException

Specified by:

sizeInternal in class AbstractSailConnection

Throws:

SailException

startTransactionInternal

protected void startTransactionInternal()
                                 throws SailException

Specified by:

startTransactionInternal in class AbstractSailConnection

Throws:

SailException

getWriteStrategyInternal

protected WriteStrategy getWriteStrategyInternal()
                                          throws SailException

Return the initialized writeStrategy. If this has not been done yet, WriteStrategy#initialize() is returned. This method guarantees lazy initialization upon the first write operation on this FedXConnection instance.

Returns:

the WriteStrategy

Throws:

SailException

pendingRemovals

public boolean pendingRemovals()

Description copied from interface: SailConnection

Indicates if the Sail has any statement removal operations pending (not yet flushed) for the current transaction.

Specified by:

pendingRemovals in interface SailConnection

Overrides:

pendingRemovals in class AbstractSailConnection

Returns:

true if any statement removal operations have not yet been flushed, false otherwise.

See Also:

• SailConnection.flush()

explain

public Explanation explain(Explanation.Level level,
 TupleExpr tupleExpr,
 Dataset dataset,
 BindingSet bindings,
 boolean includeInferred,
 int timeoutSeconds)

Description copied from interface: SailConnection

Explain how the TupleExpr will be (or has been) executed/evaluated by returning a TupleExpr (which may or may not be the provided TupleExpr) that has gone through zero or more of the stages prior to and also including execution as specified by the provided level.

This method is used by the Query interface.

WARNING: This method is experimental and is subject to change or removal without warning. There is currently only partial support for this method in RDF4J and and UnsupportedOperationException where support is lacking.

Parameters:

level - the explanation level, eg. OPTIMIZED

tupleExpr - The tuple expression to evaluate. Mutable.

dataset - The dataset to use for evaluating the query, null to use the Sail's default dataset.

bindings - A set of input parameters for the query evaluation. The keys reference variable names that should be bound to the value they map to.

includeInferred - Indicates whether inferred triples are to be considered in the query result. If false, no inferred statements are returned; if true, inferred statements are returned if available

timeoutSeconds - for explanations that require execution a timeout can be provided in seconds

Returns:

The resulting tuple expression after being run through the specified level