Package org.eclipse.rdf4j.federated.evaluation.concurrent

Class ParallelExecutorBase<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>

Type Parameters:

T -

All Implemented Interfaces:

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

Direct Known Subclasses:

JoinExecutorBase, UnionExecutorBase

public abstract class ParallelExecutorBase<T>
extends LookAheadIteration<T>
implements ParallelExecutor<T>

Base class for common parallel executors such as JoinExecutorBase and UnionExecutorBase.

Author:

Andreas Schwarte

See Also:

• JoinExecutorBase
• UnionExecutorBase

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor	Description
ParallelExecutorBase(QueryInfo queryInfo)

Method Summary

Modifier and Type	Method	Description
void	addResult(CloseableIteration<T> res)	Handle the result appropriately, e.g.
protected void	checkTimeout()	Checks whether the query execution has run into a timeout.
void	done()	Inform the controlling instance that some job is done from a different thread.
String	getDisplayId()
protected String	getExecutorType()
protected String	getId()
T	getNextElement()	Gets the next element.
QueryInfo	getQueryInfo()	Return the query info of the associated query
void	handleClose()	Called by AbstractCloseableIteration.close() when it is called for the first time.
boolean	isFinished()	Return true if this executor is finished or aborted
protected abstract void	performExecution()	Perform the parallel execution.
final void	run()
void	toss(Exception e)	Toss some exception to the controlling instance
String	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

log

protected static final org.slf4j.Logger log

NEXT_EXECUTOR_ID

protected static final AtomicLong NEXT_EXECUTOR_ID

strategy

protected final FederationEvalStrategy strategy

executorId

protected final long executorId

queryInfo

protected final QueryInfo queryInfo

evaluationThread

protected volatile Thread evaluationThread

rightQueue

protected FedXQueueCursor<T> rightQueue

rightIter

protected volatile CloseableIteration<T> rightIter

finished

protected volatile boolean finished

Constructor Details

ParallelExecutorBase

public ParallelExecutorBase(QueryInfo queryInfo)
                     throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Details

run

public final void run()

Specified by:

run in interface Runnable

performExecution

protected abstract void performExecution()
                                  throws Exception

Perform the parallel execution.

Note that this method must block until the execution is completed.

Throws:

Exception

addResult

public void addResult(CloseableIteration<T> res)

Description copied from interface: ParallelExecutor

Handle the result appropriately, e.g. add it to the result iteration. Take care for synchronization in a multithreaded environment

Specified by:

addResult in interface ParallelExecutor<T>

Parameters:

res -

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>

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>

Parameters:

e -

getNextElement

public T getNextElement()
                 throws QueryEvaluationException

Description copied from class: LookAheadIteration

Gets the next element. Subclasses should implement this method so that it returns the next element.

Specified by:

getNextElement in class LookAheadIteration<T>

Returns:

The next element, or null if no more elements are available.

Throws:

QueryEvaluationException

checkTimeout

protected void checkTimeout()
                     throws QueryInterruptedException

Checks whether the query execution has run into a timeout. If so, a QueryInterruptedException is thrown.

Throws:

QueryInterruptedException

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.

Specified by:

handleClose in class AbstractCloseableIteration<T>

Throws:

QueryEvaluationException

isFinished

public boolean isFinished()

Return true if this executor is finished or aborted

Specified by:

isFinished in interface ParallelExecutor<T>

Returns:

whether the executor is finished

getQueryInfo

public QueryInfo getQueryInfo()

Description copied from interface: ParallelExecutor

Return the query info of the associated query

Specified by:

getQueryInfo in interface ParallelExecutor<T>

Returns:

the query info

getId

protected String getId()

Returns:

a unique identifier of this execution

getDisplayId

public String getDisplayId()

getExecutorType

protected String getExecutorType()

Returns:

the executor type, e.g. "Join". Default "Executor"

toString

public String toString()

Overrides:

toString in class Object