Package org.eclipse.rdf4j.query.algebra.evaluation.iterator

Class AsyncIteratorReadAhead

java.lang.Object

org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration<BindingSet>

org.eclipse.rdf4j.common.iteration.LookAheadIteration<BindingSet>

org.eclipse.rdf4j.query.algebra.evaluation.iterator.AsyncIteratorReadAhead

All Implemented Interfaces:

AutoCloseable, Iterator<BindingSet>, CloseableIteration<BindingSet>

@Experimental
public class AsyncIteratorReadAhead
extends LookAheadIteration<BindingSet>

Author:

Håvard M. Ottestad

Constructor Summary

Constructors

Constructor	Description
AsyncIteratorReadAhead(CloseableIteration<BindingSet> iteration)

Method Summary

Modifier and Type	Method	Description
static CloseableIteration<BindingSet>	getInstance(QueryEvaluationStep iterationPrepared, BindingSet bindings, QueryEvaluationContext context)
protected BindingSet	getNextElement()	Gets the next element.
protected void	handleClose()	Called by AbstractCloseableIteration.close() when it is called for the first time.

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Details

AsyncIteratorReadAhead

public AsyncIteratorReadAhead(CloseableIteration<BindingSet> iteration)
                       throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Details

getInstance

public static CloseableIteration<BindingSet> getInstance(QueryEvaluationStep iterationPrepared,
 BindingSet bindings,
 QueryEvaluationContext context)

getNextElement

protected BindingSet getNextElement()
                             throws QueryEvaluationException

Description copied from class: LookAheadIteration

Gets the next element. Subclasses should implement this method so that it returns the next element.

Specified by:

getNextElement in class LookAheadIteration<BindingSet>

Returns:

The next element, or null if no more elements are available.

Throws:

QueryEvaluationException

handleClose

protected void handleClose()
                    throws QueryEvaluationException

Description copied from class: AbstractCloseableIteration

Called by AbstractCloseableIteration.close() when it is called for the first time. This method is only called once on each iteration. By default, this method does nothing.

Specified by:

handleClose in class AbstractCloseableIteration<BindingSet>

Throws:

QueryEvaluationException