Package org.eclipse.rdf4j.federated.evaluation.join

Class ControlledWorkerBoundJoin

java.lang.Object

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

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

org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase<T>

org.eclipse.rdf4j.federated.evaluation.join.JoinExecutorBase<BindingSet>

org.eclipse.rdf4j.federated.evaluation.join.ControlledWorkerJoin

org.eclipse.rdf4j.federated.evaluation.join.ControlledWorkerBoundJoin

All Implemented Interfaces:

AutoCloseable, Runnable, CloseableIteration<BindingSet,QueryEvaluationException>, Iteration<BindingSet,QueryEvaluationException>, ParallelExecutor<BindingSet>

public class ControlledWorkerBoundJoin
extends ControlledWorkerJoin

Execute the nested loop join in an asynchronous fashion, using grouped requests, i.e. group bindings into one SPARQL request using the UNION operator. The number of concurrent threads is controlled by a ControlledWorkerScheduler which works according to the FIFO principle and uses worker threads. This join cursor blocks until all scheduled tasks are finished, however the result iteration can be accessed from different threads to allow for pipelining.

Author:

Andreas Schwarte

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	ControlledWorkerBoundJoin.BoundJoinTaskCreator
protected class	ControlledWorkerBoundJoin.CheckJoinTaskCreator
protected class	ControlledWorkerBoundJoin.FedXServiceJoinTaskCreator
protected static interface	ControlledWorkerBoundJoin.TaskCreator

Field Summary

Fields inherited from class org.eclipse.rdf4j.federated.evaluation.join.ControlledWorkerJoin

phaser, scheduler

Fields inherited from class org.eclipse.rdf4j.federated.evaluation.join.JoinExecutorBase

bindings, joinVars, leftIter, rightArg

Fields inherited from class org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase

evaluationThread, executorId, finished, NEXT_EXECUTOR_ID, queryInfo, rightIter, rightQueue, strategy

Constructor Summary

Constructors

Constructor	Description
ControlledWorkerBoundJoin(ControlledWorkerScheduler<BindingSet> scheduler, FederationEvalStrategy strategy, CloseableIteration<BindingSet,QueryEvaluationException> leftIter, TupleExpr rightArg, BindingSet bindings, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method	Description
protected void	handleBindings()	Implementations must implement this method to handle bindings.
void	handleClose()	Called by AbstractCloseableIteration.close() when it is called for the first time.

Methods inherited from class org.eclipse.rdf4j.federated.evaluation.join.JoinExecutorBase

getExecutorType, getJoinVars, performExecution, setJoinVars

Methods inherited from class org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase

addResult, checkTimeout, done, getDisplayId, getId, getNextElement, getQueryInfo, isFinished, run, toss, 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

Methods inherited from interface org.eclipse.rdf4j.common.iteration.Iteration

stream

Constructor Details

ControlledWorkerBoundJoin

public ControlledWorkerBoundJoin(ControlledWorkerScheduler<BindingSet> scheduler,
 FederationEvalStrategy strategy,
 CloseableIteration<BindingSet,QueryEvaluationException> leftIter,
 TupleExpr rightArg,
 BindingSet bindings,
 QueryInfo queryInfo)
                          throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Details

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 Note that the implementation must block until the entire join is executed.

Overrides:

handleBindings in class ControlledWorkerJoin

Throws:

Exception

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 ControlledWorkerJoin

Throws:

QueryEvaluationException