org.openrdf.query.algebra.evaluation.federation

Class ServiceFallbackIteration

java.lang.Object

info.aduna.iteration.CloseableIterationBase<E,X>

info.aduna.iteration.LookAheadIteration<T,QueryEvaluationException>

org.openrdf.query.algebra.evaluation.federation.JoinExecutorBase<BindingSet>

org.openrdf.query.algebra.evaluation.federation.ServiceFallbackIteration

All Implemented Interfaces:

CloseableIteration<BindingSet,QueryEvaluationException>, Iteration<BindingSet,QueryEvaluationException>

public class ServiceFallbackIteration
extends JoinExecutorBase<BindingSet>

Fallback join handler, if the block join can not be performed, e.g. because the BINDINGS clause is not supported by the endpoint. Gets a materialized collection of bindings as input, and has to evaluate the join.

Author:

Andreas Schwarte

Field Summary

Fields

Modifier and Type	Field and Description
protected Collection<BindingSet>	bindings
protected FederatedService	federatedService
protected Set<String>	projectionVars
protected Service	service

Fields inherited from class org.openrdf.query.algebra.evaluation.federation.JoinExecutorBase

closed, finished, leftIter, NEXT_JOIN_ID, rightArg, rightIter, rightQueue

Constructor Summary

Constructors

Constructor and Description
ServiceFallbackIteration(Service service, Set<String> projectionVars, Collection<BindingSet> bindings, FederatedService federatedService)

Method Summary

Modifier and Type	Method and Description
protected void	handleBindings() Implementations must implement this method to handle bindings.

Methods inherited from class org.openrdf.query.algebra.evaluation.federation.JoinExecutorBase

addResult, done, getNextElement, handleClose, isFinished, run, toss

Methods inherited from class info.aduna.iteration.LookAheadIteration

hasNext, next, remove

Methods inherited from class info.aduna.iteration.CloseableIterationBase

close, isClosed

Methods inherited from class java.lang.Object

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

Field Detail

service

protected final Service service

projectionVars

protected final Set<String> projectionVars

federatedService

protected final FederatedService federatedService

bindings

protected final Collection<BindingSet> bindings

Constructor Detail

ServiceFallbackIteration

public ServiceFallbackIteration(Service service,
                                Set<String> projectionVars,
                                Collection<BindingSet> bindings,
                                FederatedService federatedService)
                         throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Detail

handleBindings

protected void handleBindings()
                       throws Exception

Description copied from class: JoinExecutorBase

Implementations must implement this method to handle bindings. Use the following as a template while (!closed && leftIter.hasNext()) { // your code } and add results to rightQueue. Note that addResult() is implemented synchronized and thus thread safe. In case you can guarantee sequential access, it is also possible to directly access rightQueue

Specified by:

handleBindings in class JoinExecutorBase<BindingSet>

Throws:

Exception