org.eclipse.rdf4j.federated.evaluation.union

Class UnionExecutorBase<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.union.UnionExecutorBase<T>

All Implemented Interfaces:

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

Direct Known Subclasses:

WorkerUnionBase

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

Base class for any parallel union 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 inherited from class org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase

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

Constructor Summary

Constructors

Constructor and Description
UnionExecutorBase(FederationEvalStrategy strategy, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method and Description
protected String	getExecutorType()
protected void	performExecution() Perform the parallel execution.
protected abstract void	union() Note: this method must block until the union is executed completely.

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

addResult, checkTimeout, done, getDisplayId, getId, getNextElement, getQueryInfo, handleClose, 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 Detail

UnionExecutorBase

public UnionExecutorBase(FederationEvalStrategy strategy,
                         QueryInfo queryInfo)

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

union

protected abstract void union()
                       throws Exception

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.

Throws:

Exception

getExecutorType

protected String getExecutorType()

Overrides:

getExecutorType in class ParallelExecutorBase<T>

Returns:

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