Package org.eclipse.rdf4j.repository.sparql.federation

Class JoinExecutorBase<T>

java.lang.Object

org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration<E,X>

org.eclipse.rdf4j.common.iteration.LookAheadIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>

org.eclipse.rdf4j.repository.sparql.federation.JoinExecutorBase<T>

All Implemented Interfaces:

AutoCloseable, org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>, org.eclipse.rdf4j.common.iteration.Iteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>

public abstract class JoinExecutorBase<T>
extends org.eclipse.rdf4j.common.iteration.LookAheadIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>

Base class for any join parallel join executor. Note that this class extends LookAheadIteration and thus any implementation of this class is applicable for pipelining when used in a different thread (access to shared variables is synchronized).

Author:

Andreas Schwarte

Field Summary

Fields

Modifier and Type	Field	Description
protected org.eclipse.rdf4j.query.BindingSet	bindings
protected boolean	closed	Deprecated. Use AbstractCloseableIteration.isClosed() instead.
protected boolean	finished	Deprecated. Use isFinished() instead.
protected org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>	leftIter
protected static int	NEXT_JOIN_ID	Deprecated. No replacement, don't use static shared int variables.
protected org.eclipse.rdf4j.query.algebra.TupleExpr	rightArg
protected org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>	rightIter
protected QueueCursor<org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>>	rightQueue

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JoinExecutorBase(org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException> leftIter, org.eclipse.rdf4j.query.algebra.TupleExpr rightArg, org.eclipse.rdf4j.query.BindingSet bindings)

Method Summary

Modifier and Type	Method	Description
void	addResult(org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException> res)
void	done()
T	getNextElement()
protected abstract void	handleBindings()	Implementations must implement this method to handle bindings.
void	handleClose()
boolean	isFinished()	Gets whether this executor is finished or aborted.
void	run()
void	toss(Exception e)

Methods inherited from class org.eclipse.rdf4j.common.iteration.LookAheadIteration

hasNext, next, remove

Methods inherited from class org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration

close, isClosed

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.common.iteration.CloseableIteration

stream

Field Detail

NEXT_JOIN_ID

protected static int NEXT_JOIN_ID

Deprecated.

No replacement, don't use static shared int variables.

rightArg

protected final org.eclipse.rdf4j.query.algebra.TupleExpr rightArg

bindings

protected final org.eclipse.rdf4j.query.BindingSet bindings

leftIter

protected final org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException> leftIter

rightIter

protected volatile org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException> rightIter

closed

protected volatile boolean closed

Deprecated.

Use AbstractCloseableIteration.isClosed() instead.

finished

protected volatile boolean finished

Deprecated.

Use isFinished() instead.

rightQueue

protected final QueueCursor<org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>> rightQueue

Constructor Detail

JoinExecutorBase

protected JoinExecutorBase(org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException> leftIter,
                           org.eclipse.rdf4j.query.algebra.TupleExpr rightArg,
                           org.eclipse.rdf4j.query.BindingSet bindings)
                    throws org.eclipse.rdf4j.query.QueryEvaluationException

Throws:

org.eclipse.rdf4j.query.QueryEvaluationException

Method Detail

run

public final void run()

handleBindings

protected abstract void handleBindings()
                                throws Exception

Implementations must implement this method to handle bindings. Use the following as a template while (!closed && leftIter.hasNext()) { // your code } and add results to rightQueue. Note that addResult() is implemented synchronized and thus thread safe. In case you can guarantee sequential access, it is also possible to directly access rightQueue

Throws:

Exception

addResult

public void addResult(org.eclipse.rdf4j.common.iteration.CloseableIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException> res)

done

public void done()

toss

public void toss(Exception e)

getNextElement

public T getNextElement()
                 throws org.eclipse.rdf4j.query.QueryEvaluationException

Specified by:

getNextElement in class org.eclipse.rdf4j.common.iteration.LookAheadIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>

Throws:

org.eclipse.rdf4j.query.QueryEvaluationException

handleClose

public void handleClose()
                 throws org.eclipse.rdf4j.query.QueryEvaluationException

Overrides:

handleClose in class org.eclipse.rdf4j.common.iteration.LookAheadIteration<T,org.eclipse.rdf4j.query.QueryEvaluationException>

Throws:

org.eclipse.rdf4j.query.QueryEvaluationException

isFinished

public boolean isFinished()

Gets whether this executor is finished or aborted.

Returns:

true if this executor is finished or aborted