Class LookAheadIteration<E,X extends Exception>
- java.lang.Object
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- org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration<E,X>
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- org.eclipse.rdf4j.common.iteration.LookAheadIteration<E,X>
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- All Implemented Interfaces:
AutoCloseable,CloseableIteration<E,X>,Iteration<E,X>
- Direct Known Subclasses:
BottomUpJoinIterator,CrossProductIteration,DescribeIteration,DistinctModelReducingUnionIteration,FilteringIteration,HashJoinIteration,IndependentJoingroupBindingsIteration,IndependentJoingroupBindingsIteration2,IndependentJoingroupBindingsIteration3,JoinExecutorBase,JoinIterator,LeftJoinIterator,MemStatementIterator,MultiProjectionIterator,ParallelExecutorBase,ParallelServiceExecutor,PathIteration,QueueIteration,SPARQLCrossProductIteration,UnionIteration,ZeroLengthPathIteration
public abstract class LookAheadIteration<E,X extends Exception> extends AbstractCloseableIteration<E,X>
An Iteration that looks one element ahead, if necessary, to handle calls tohasNext(). 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.
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Constructor Summary
Constructors Modifier Constructor Description protectedLookAheadIteration()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected abstract EgetNextElement()Gets the next element.protected voidhandleClose()Called byAbstractCloseableIteration.close()when it is called for the first time.booleanhasNext()Returns true if the iteration has more elements.Enext()Returns the next element in the iteration.voidremove()Throws anUnsupportedOperationException.-
Methods inherited from class org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration
close, isClosed
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Method Detail
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getNextElement
protected abstract E getNextElement() throws X extends Exception
Gets the next element. Subclasses should implement this method so that it returns the next element.
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hasNext
public final boolean hasNext() throws X extends ExceptionDescription copied from interface:IterationReturns true if the iteration has more elements. (In other words, returns true ifIteration.next()would return an element rather than throwing a NoSuchElementException.)
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next
public final E next() throws X extends Exception
Description copied from interface:IterationReturns the next element in the iteration.
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remove
public void remove()
Throws anUnsupportedOperationException.
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handleClose
protected void handleClose() throws X extends ExceptionDescription copied from class:AbstractCloseableIterationCalled byAbstractCloseableIteration.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:
handleClosein classAbstractCloseableIteration<E,X extends Exception>- Throws:
XX extends Exception
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