Class ControlledWorkerUnion<T>

java.lang.Object

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

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

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

org.eclipse.rdf4j.federated.evaluation.union.UnionExecutorBase<T>

org.eclipse.rdf4j.federated.evaluation.union.WorkerUnionBase<T>

org.eclipse.rdf4j.federated.evaluation.union.ControlledWorkerUnion<T>

All Implemented Interfaces:

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

public class ControlledWorkerUnion<T>
extends WorkerUnionBase<T>

Execution of union tasks with ControlledWorkerScheduler. Tasks can be added using the provided functions. Note that the union operation is to be executed with the ParallelExecutorBase.run() method (also threaded execution is possible). Results are then contained in this iteration.

Author:

Andreas Schwarte

Field Summary

Fields

Modifier and Type	Field	Description
static int	awakeCount
protected final Phaser	phaser
protected final ControlledWorkerScheduler<T>	scheduler
static int	waitingCount

Fields inherited from class WorkerUnionBase

tasks

Modifier and Type	Field	Description
protected List<ParallelTask<T>>	tasks

Fields inherited from class ParallelExecutorBase

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

Modifier and Type	Field	Description
protected Thread	evaluationThread
protected final long	executorId
protected boolean	finished
protected static final org.slf4j.Logger	log
protected static final AtomicLong	NEXT_EXECUTOR_ID
protected final QueryInfo	queryInfo
protected CloseableIteration<T>	rightIter
protected FedXQueueCursor<T>	rightQueue
protected final FederationEvalStrategy	strategy

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
ControlledWorkerUnion(ControlledWorkerScheduler<T> scheduler, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method	Description
void	done()	Inform the controlling instance that some job is done from a different thread.
void	handleClose()	Called by AbstractCloseableIteration.close() when it is called for the first time.
void	toss(Exception e)	Toss some exception to the controlling instance
protected void	union()	Note: this method must block until the union is executed completely.

Methods inherited from class WorkerUnionBase

addTask

Modifier and Type	Method	Description
void	addTask(ParallelTask<T> task)	Add a generic parallel task.

Methods inherited from class UnionExecutorBase

getExecutorType, performExecution

Modifier and Type	Method	Description
protected String	getExecutorType()
protected final void	performExecution()	Perform the parallel execution.

Methods inherited from class ParallelExecutorBase

addResult, checkTimeout, getDisplayId, getId, getNextElement, getQueryInfo, isFinished, run, toString

Modifier and Type	Method	Description
void	addResult(CloseableIteration<T> res)	Handle the result appropriately, e.g. add it to the result iteration.
protected void	checkTimeout()	Checks whether the query execution has run into a timeout.
String	getDisplayId()
protected String	getId()
T	getNextElement()	Gets the next element.
QueryInfo	getQueryInfo()	Return the query info of the associated query
boolean	isFinished()	Return true if this executor is finished or aborted
final void	run()
String	toString()

Methods inherited from class LookAheadIteration

hasNext, next, remove

Modifier and Type	Method	Description
final boolean	hasNext()
final T	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, wait, wait, wait

Methods inherited from interface CloseableIteration

stream

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

Methods inherited from interface Iterator

forEachRemaining

Field Details

waitingCount

public static int waitingCount

awakeCount

public static int awakeCount

scheduler

protected final ControlledWorkerScheduler<T> scheduler

phaser

protected final Phaser phaser

Constructor Details

ControlledWorkerUnion

public ControlledWorkerUnion(ControlledWorkerScheduler<T> scheduler,
 QueryInfo queryInfo)

Method Details

union

protected void union()
              throws Exception

Description copied from class: UnionExecutorBase

Note: this method must block until the union is executed completely. Otherwise the result queue is marked as committed while this isn't the case. The blocking behavior in general is no problem: If you need concurrent access to the result (i.e. pipelining) just run the union in a separate thread. Access to the result iteration is synchronized.

Specified by:

union in class UnionExecutorBase<T>

Throws:

Exception

done

public void done()

Description copied from interface: ParallelExecutor

Inform the controlling instance that some job is done from a different thread. In most cases this is a no-op.

Specified by:

done in interface ParallelExecutor<T>

Overrides:

done in class ParallelExecutorBase<T>

toss

public void toss(Exception e)

Description copied from interface: ParallelExecutor

Toss some exception to the controlling instance

Specified by:

toss in interface ParallelExecutor<T>

Overrides:

toss in class ParallelExecutorBase<T>

Parameters:

e -

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 WorkerUnionBase<T>

Throws:

QueryEvaluationException