org.eclipse.rdf4j.sail.federation.evaluation

Class AlternativeCursor<E>

java.lang.Object

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

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

org.eclipse.rdf4j.sail.federation.evaluation.AlternativeCursor<E>

All Implemented Interfaces:

AutoCloseable, CloseableIteration<E,QueryEvaluationException>, Iteration<E,QueryEvaluationException>

public class AlternativeCursor<E>
extends LookAheadIteration<E,QueryEvaluationException>

If the primary cursor is empty, use the alternative cursor.

Author:

James Leigh

Constructor Summary

Constructors

Constructor and Description
AlternativeCursor(CloseableIteration<? extends E,QueryEvaluationException> primary, CloseableIteration<? extends E,QueryEvaluationException> alternative)

Method Summary

Modifier and Type	Method and Description
E	getNextElement() Gets the next element.
void	handleClose() Called by AbstractCloseableIteration.close() when it is called for the first time.
String	toString()

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, wait, wait, wait

Constructor Detail

AlternativeCursor

public AlternativeCursor(CloseableIteration<? extends E,QueryEvaluationException> primary,
                         CloseableIteration<? extends E,QueryEvaluationException> alternative)

Method Detail

handleClose

public 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.

Overrides:

handleClose in class LookAheadIteration<E,QueryEvaluationException>

Throws:

QueryEvaluationException

getNextElement

public E 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<E,QueryEvaluationException>

Returns:

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

Throws:

QueryEvaluationException

toString

public String toString()

Overrides:

toString in class Object