org.eclipse.rdf4j.federated.evaluation.join

Class JoinExecutorBase<T>

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<T>

All Implemented Interfaces:

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

Direct Known Subclasses:

ControlledWorkerJoin, ControlledWorkerLeftJoin, HashJoin, SynchronousJoin

public abstract class JoinExecutorBase<T>
extends ParallelExecutorBase<T>

Base class for any join parallel join executor. Note that this class extends LookAheadIteration and thus any implementation of this class is applicable for pipelining when used in a different thread (access to shared variables is synchronized).

Author:

Andreas Schwarte

Field Summary

Fields

Modifier and Type	Field and Description
protected BindingSet	bindings
protected Set<String>	joinVars
protected CloseableIteration<T,QueryEvaluationException>	leftIter
protected TupleExpr	rightArg

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

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

Constructor Summary

Constructors

Constructor and Description
JoinExecutorBase(FederationEvalStrategy strategy, CloseableIteration<T,QueryEvaluationException> leftIter, TupleExpr rightArg, BindingSet bindings, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method and Description
protected String	getExecutorType()
Set<String>	getJoinVars()
protected abstract void	handleBindings() Implementations must implement this method to handle bindings.
void	handleClose() Called by AbstractCloseableIteration.close() when it is called for the first time.
protected void	performExecution() Perform the parallel execution.
void	setJoinVars(Set<String> joinVars) Set the join variables

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

Field Detail

rightArg

protected final TupleExpr rightArg

bindings

protected final BindingSet bindings

joinVars

protected Set<String> joinVars

leftIter

protected CloseableIteration<T,QueryEvaluationException> leftIter

Constructor Detail

JoinExecutorBase

public JoinExecutorBase(FederationEvalStrategy strategy,
                        CloseableIteration<T,QueryEvaluationException> leftIter,
                        TupleExpr rightArg,
                        BindingSet bindings,
                        QueryInfo queryInfo)
                 throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Detail

performExecution

protected final void performExecution()
                               throws Exception

Description copied from class: ParallelExecutorBase

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

Specified by:

performExecution in class ParallelExecutorBase<T>

Throws:

Exception

handleBindings

protected abstract void handleBindings()
                                throws Exception

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.

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 ParallelExecutorBase<T>

Throws:

QueryEvaluationException

getExecutorType

protected String getExecutorType()

Overrides:

getExecutorType in class ParallelExecutorBase<T>

Returns:

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

getJoinVars

public Set<String> getJoinVars()

Returns:

the join variables, might be null if unknown in the concrete implementation

setJoinVars

public void setJoinVars(Set<String> joinVars)

Set the join variables

Parameters:

joinVars - the join variables