Class LookAheadIteration<E>

java.lang.Object

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

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

All Implemented Interfaces:

AutoCloseable, Iterator<E>, CloseableIteration<E>

Direct Known Subclasses:

AsyncIteratorBuffer, AsyncIteratorDirect, AsyncIteratorReadAhead, BindLeftJoinIteration, CrossProductIteration, DescribeIteration, DistinctModelReducingUnionIteration, FedXPathIteration, FedXZeroLengthPathIteration, FilteringIteration, HashJoinIteration, IndependentJoingroupBindingsIteration, IndependentJoingroupBindingsIteration2, IndependentJoingroupBindingsIteration3, JoinExecutorBase, JoinIterator, LeftJoinIterator, MemTripleIterator, MultiProjectionIterator, ParallelExecutorBase, ParallelServiceExecutor, PathIteration, QueueIteration, SortedIteration, SPARQLCrossProductIteration, UnionIteration, ZeroLengthPathIteration

public abstract class LookAheadIteration<E>
extends AbstractCloseableIteration<E>

An Iteration that looks one element ahead, if necessary, to handle calls to hasNext(). This is a convenient super class for Iterations that have no easy way to tell if there are any more results, but still should implement the java.util.Iteration interface.

Field Summary

Fields inherited from interface CloseableIteration

EMPTY_STATEMENT_ITERATION

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	LookAheadIteration()

Method Summary

Modifier and Type	Method	Description
protected abstract E	getNextElement()	Gets the next element.
final boolean	hasNext()
final E	next()
void	remove()	Throws an UnsupportedOperationException.

Methods inherited from class AbstractCloseableIteration

close, handleClose, isClosed

Methods inherited from class Object

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

Methods inherited from interface CloseableIteration

stream

Methods inherited from interface Iterator

forEachRemaining

Constructor Details

LookAheadIteration

protected LookAheadIteration()

Method Details

getNextElement

protected abstract E getNextElement()

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

Returns:

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

hasNext

public final boolean hasNext()

next

public final E next()

remove

public void remove()

Throws an UnsupportedOperationException.