Class FederatedDescribeIteration

java.lang.Object

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

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

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

org.eclipse.rdf4j.federated.evaluation.iterator.FederatedDescribeIteration

All Implemented Interfaces:

AutoCloseable, Iterator<BindingSet>, CloseableIteration<BindingSet>

public class FederatedDescribeIteration
extends DescribeIteration

Specialized DescribeIteration for evaluation of DESCRIBE queries in the federation. ‚

Author:

Andreas Schwarte

Field Summary

Fields inherited from class DescribeIteration

parentBindings, VARNAME_OBJECT, VARNAME_PREDICATE, VARNAME_SUBJECT

Modifier and Type	Field	Description
protected BindingSet	parentBindings
protected static final String	VARNAME_OBJECT
protected static final String	VARNAME_PREDICATE
protected static final String	VARNAME_SUBJECT

Fields inherited from interface CloseableIteration

EMPTY_STATEMENT_ITERATION

Modifier and Type	Field	Description
static final EmptyIteration<Statement>	EMPTY_STATEMENT_ITERATION

Constructor Summary

Constructors

Constructor	Description
FederatedDescribeIteration(CloseableIteration<BindingSet> sourceIter, FederationEvaluationStrategy strategy, Set<String> describeExprNames, BindingSet parentBindings, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method	Description
protected CloseableIteration<BindingSet>	createNextIteration(Value subject, Value object)
protected void	handleClose()	Called by AbstractCloseableIteration.close() when it is called for the first time.

Methods inherited from class DescribeIteration

getNextElement

Modifier and Type	Method	Description
protected BindingSet	getNextElement()	Gets the next element.

Methods inherited from class LookAheadIteration

hasNext, next, remove

Modifier and Type	Method	Description
final boolean	hasNext()
final BindingSet	next()
void	remove()	Throws an UnsupportedOperationException.

Methods inherited from class AbstractCloseableIteration

close, isClosed

Modifier and Type	Method	Description
final void	close()	Calls AbstractCloseableIteration.handleClose() upon first call and makes sure the resource closures are only executed once.
final boolean	isClosed()	Checks whether this CloseableIteration has been closed.

Methods inherited from class Object

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

Methods inherited from interface CloseableIteration

stream

Modifier and Type	Method	Description
default Stream<BindingSet>	stream()	Convert the results to a Java 8 Stream.

Methods inherited from interface Iterator

forEachRemaining

Constructor Details

FederatedDescribeIteration

public FederatedDescribeIteration(CloseableIteration<BindingSet> sourceIter,
 FederationEvaluationStrategy strategy,
 Set<String> describeExprNames,
 BindingSet parentBindings,
 QueryInfo queryInfo)

Method Details

createNextIteration

protected CloseableIteration<BindingSet> createNextIteration(Value subject,
 Value object)
                                                      throws QueryEvaluationException

Overrides:

createNextIteration in class DescribeIteration

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.

Overrides:

handleClose in class DescribeIteration

Throws:

QueryEvaluationException