org.eclipse.rdf4j.query.algebra.evaluation.federation

Class ServiceJoinIterator

java.lang.Object

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

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

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

org.eclipse.rdf4j.query.algebra.evaluation.federation.JoinExecutorBase<BindingSet>

org.eclipse.rdf4j.query.algebra.evaluation.federation.ServiceJoinIterator

All Implemented Interfaces:

AutoCloseable, CloseableIteration<BindingSet,QueryEvaluationException>, Iteration<BindingSet,QueryEvaluationException>

public class ServiceJoinIterator
extends JoinExecutorBase<BindingSet>

Iterator for efficient SERVICE evaluation (vectored). SERVICE is the right handside argument of this join.

Author:

Andreas Schwarte

Field Summary

Fields

Modifier and Type	Field and Description
protected Service	service
protected EvaluationStrategy	strategy

Fields inherited from class org.eclipse.rdf4j.repository.sparql.federation.JoinExecutorBase

bindings, closed, finished, leftIter, NEXT_JOIN_ID, rightArg, rightIter, rightQueue

Constructor Summary

Constructors

Constructor and Description
ServiceJoinIterator(CloseableIteration<BindingSet,QueryEvaluationException> leftIter, Service service, BindingSet bindings, EvaluationStrategy strategy) Construct a service join iteration to use vectored evaluation.

Method Summary

Modifier and Type	Method and Description
protected void	handleBindings() Implementations must implement this method to handle bindings.

Methods inherited from class org.eclipse.rdf4j.repository.sparql.federation.JoinExecutorBase

addResult, done, getNextElement, handleClose, isFinished, run, toss

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.Iteration

stream

Field Detail

service

protected Service service

strategy

protected EvaluationStrategy strategy

Constructor Detail

ServiceJoinIterator

public ServiceJoinIterator(CloseableIteration<BindingSet,QueryEvaluationException> leftIter,
                           Service service,
                           BindingSet bindings,
                           EvaluationStrategy strategy)
                    throws QueryEvaluationException

Construct a service join iteration to use vectored evaluation. The constructor automatically starts evaluation.

Parameters:

leftIter -

service -

bindings -

strategy -

Throws:

QueryEvaluationException

Method Detail

handleBindings

protected void handleBindings()
                       throws Exception

Description copied from class: JoinExecutorBase

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

Specified by:

handleBindings in class JoinExecutorBase<BindingSet>

Throws:

Exception