Class ExecOpDuplicateRemoval

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.UnaryExecutableOpBase

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.ExecOpDuplicateRemoval

All Implemented Interfaces:

StatsProvider, ExecutableOperator, UnaryExecutableOp

public class ExecOpDuplicateRemoval
extends UnaryExecutableOpBase

To be used for DISTINCT clauses. This algorithm removes duplicates by collecting input solution mappings in the same hash set. Passes only distinct solution mappings to its output. Duplicates are based on SolutionMapping equality, not object identity.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Set<SolutionMapping>	distinctSolMaps

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

collectExceptions, qpInfo

Constructor Summary

Constructors

Constructor	Description
ExecOpDuplicateRemoval(boolean collectExceptions, QueryPlanningInfo qpInfo)

Method Summary

Modifier and Type	Method	Description
protected void	_concludeExecution(IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to conclude the execution of this operator and send the remaining result elements (if any) to the given sink.
protected void	_process(SolutionMapping inputSolMap, IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to process the given solution mapping as input and send the produced result elements (if any) to the given sink.
protected ExecutableOperatorStatsImpl	createStats()
void	resetStats()

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.UnaryExecutableOpBase

_process, concludeExecution, getStats, process, process

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

getExceptionsCaughtDuringExecution, getQueryPlanningInfo, recordExceptionCaughtDuringExecution

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.executable.ExecutableOperator

getExceptionsCaughtDuringExecution, getQueryPlanningInfo

Field Details

distinctSolMaps

protected final Set<SolutionMapping> distinctSolMaps

Constructor Details

ExecOpDuplicateRemoval

public ExecOpDuplicateRemoval(boolean collectExceptions,
 QueryPlanningInfo qpInfo)

Method Details

_process

protected void _process(SolutionMapping inputSolMap,
 IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: UnaryExecutableOpBase

Implementations of this function need to process the given solution mapping as input and send the produced result elements (if any) to the given sink. If an exception occurs while processing the solution mapping, then this exception needs to be thrown.

Specified by:

_process in class UnaryExecutableOpBase

_concludeExecution

protected void _concludeExecution(IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: UnaryExecutableOpBase

Implementations of this function need to conclude the execution of this operator and send the remaining result elements (if any) to the given sink. If an exception occurs during this process, then this exception needs to be thrown.

Specified by:

_concludeExecution in class UnaryExecutableOpBase

resetStats

public void resetStats()

Specified by:

resetStats in interface StatsProvider

Overrides:

resetStats in class UnaryExecutableOpBase

createStats

protected ExecutableOperatorStatsImpl createStats()

Overrides:

createStats in class UnaryExecutableOpBase