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

Class HashJoin

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<BindingSet>

org.eclipse.rdf4j.federated.evaluation.join.HashJoin

All Implemented Interfaces:

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

public class HashJoin
extends JoinExecutorBase<BindingSet>

Operator for a hash join of tuple expressions.

Since:

6.0

Author:

Andreas Schwarte

Field Summary

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, log, NEXT_EXECUTOR_ID, queryInfo, rightIter, rightQueue, strategy

Constructor Summary

Constructors

Constructor	Description
HashJoin(FederationEvalStrategy strategy, CloseableIteration<BindingSet,QueryEvaluationException> leftIter, TupleExpr rightArg, QueryEvaluationStep rightPrepared, Set<String> joinVars, BindingSet bindings, QueryInfo queryInfo)

Method Summary

Modifier and Type	Method	Description
protected void	handleBindings()	Implementations must implement this method to handle bindings.
protected void	performJoin(Collection<BindingSet> leftBlock, Collection<BindingSet> rightBlock, Set<String> joinVariables, Collection<String> freeVariablesRight)	Perform the join and add the result to this cursor.

Methods inherited from class org.eclipse.rdf4j.federated.evaluation.join.JoinExecutorBase

getExecutorType, getJoinVars, handleClose, 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

Constructor Detail

HashJoin

public HashJoin(FederationEvalStrategy strategy,
                CloseableIteration<BindingSet,QueryEvaluationException> leftIter,
                TupleExpr rightArg,
                QueryEvaluationStep rightPrepared,
                Set<String> joinVars,
                BindingSet bindings,
                QueryInfo queryInfo)
         throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Detail

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 && 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

performJoin

protected void performJoin(Collection<BindingSet> leftBlock,
                           Collection<BindingSet> rightBlock,
                           Set<String> joinVariables,
                           Collection<String> freeVariablesRight)

Perform the join and add the result to this cursor.

See join(Collection, Collection, Set, Collection) and ParallelExecutorBase.addResult(CloseableIteration).

Parameters:

leftBlock -

rightBlock -

joinVariables -

freeVariablesRight -