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

Class ControlledWorkerBindJoinBase

java.lang.Object

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

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

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

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

org.eclipse.rdf4j.federated.evaluation.join.ControlledWorkerBindJoinBase

All Implemented Interfaces:

AutoCloseable, Runnable, Iterator<BindingSet>, CloseableIteration<BindingSet>, ParallelExecutor<BindingSet>

Direct Known Subclasses:

ControlledWorkerBindJoin, ControlledWorkerBindLeftJoin

public abstract class ControlledWorkerBindJoinBase
extends JoinExecutorBase<BindingSet>

Base class for executing joins as bind joins (i.e., the bindings of a block are injected in the SPARQL query as VALUES clause). 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 static interface	ControlledWorkerBindJoinBase.TaskCreator

Field Summary

Fields

Modifier and Type	Field	Description
protected final Phaser	phaser
protected final ControlledWorkerScheduler<BindingSet>	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
ControlledWorkerBindJoinBase(ControlledWorkerScheduler<BindingSet> scheduler, FederationEvalStrategy strategy, CloseableIteration<BindingSet> leftIter, TupleExpr rightArg, BindingSet bindings, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method	Description
protected abstract ControlledWorkerBindJoinBase.TaskCreator	determineTaskCreator(TupleExpr expr, BindingSet bs)	Return the ControlledWorkerBindJoinBase.TaskCreator for executing the bind join
protected int	getNextBindJoinSize(int configuredBindJoinSize, int totalBindings)	Return the size of the next bind join block.
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.CloseableIteration

stream

Methods inherited from interface java.util.Iterator

forEachRemaining

Field Details

scheduler

protected final ControlledWorkerScheduler<BindingSet> scheduler

phaser

protected final Phaser phaser

Constructor Details

ControlledWorkerBindJoinBase

public ControlledWorkerBindJoinBase(ControlledWorkerScheduler<BindingSet> scheduler,
 FederationEvalStrategy strategy,
 CloseableIteration<BindingSet> 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 invalid input: '&'invalid input: '&' 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.

Specified by:

handleBindings in class JoinExecutorBase<BindingSet>

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 JoinExecutorBase<BindingSet>

Throws:

QueryEvaluationException

determineTaskCreator

protected abstract ControlledWorkerBindJoinBase.TaskCreator determineTaskCreator(TupleExpr expr,
 BindingSet bs)

Return the ControlledWorkerBindJoinBase.TaskCreator for executing the bind join

Parameters:

expr -

bs -

Returns:

getNextBindJoinSize

protected int getNextBindJoinSize(int configuredBindJoinSize,
 int totalBindings)

Return the size of the next bind join block.

Parameters:

configuredBindJoinSize - the configured bind join size

totalBindings - the current process bindings from the intermediate result set

Returns: