com.bigdata.bop.join

Class DistinctTermScanOp<E>

java.lang.Object

com.bigdata.bop.CoreBaseBOp

com.bigdata.bop.BOpBase

com.bigdata.bop.PipelineOp

com.bigdata.bop.join.DistinctTermScanOp<E>

All Implemented Interfaces:

BOp, IPropertySet, Serializable, Cloneable

public class DistinctTermScanOp<E>
extends PipelineOp

This operator performs a distinct terms scan for an IPredicate, binding the distinct values for the specified variable(s) from the IAccessPath for the IPredicate. This is done using a DistinctTermAdvancer to skip over any duplicate solutions in the index. Thus the cost of this operator is O(N) where N is the number of distinct solutions that exist in the index.

Author:

Bryan Thompson

See Also:

DISTINCT PREDICATEs query is slow , DistinctTermAdvancer, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	DistinctTermScanOp.Annotations

Field Summary

Fields inherited from class com.bigdata.bop.CoreBaseBOp

DEFAULT_INITIAL_CAPACITY

Fields inherited from interface com.bigdata.bop.BOp

NOANNS, NOARGS

Constructor Summary

Constructors

Constructor and Description
DistinctTermScanOp(BOp[] args, Map<String,Object> annotations) Shallow copy constructor.
DistinctTermScanOp(BOp[] args, NV... annotations)
DistinctTermScanOp(DistinctTermScanOp<E> op) Deep copy constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected IConstraint[]	constraints()
FutureTask<Void>	eval(BOpContext<IBindingSet> context) Return a FutureTask which computes the operator against the evaluation context.
protected IVariable<?>	getDistinctVar()
IPredicate<E>	getPredicate()
protected IVariable<?>[]	getSelect()

Methods inherited from class com.bigdata.bop.PipelineOp

assertAtOnceJavaHeapOp, assertMaxParallelOne, getChunkCapacity, getChunkOfChunksCapacity, getChunkTimeout, getMaxMemory, getMaxParallel, isAtOnceEvaluation, isBlockedEvaluation, isLastPassRequested, isPipelinedEvaluation, isReorderSolutions, isSharedState, newStats

Methods inherited from class com.bigdata.bop.BOpBase

__replaceArg, _clearProperty, _set, _setProperty, annotations, annotationsCopy, annotationsEqual, annotationsRef, argIterator, args, argsCopy, arity, clearAnnotations, clearProperty, deepCopy, deepCopy, get, getProperty, setArg, setProperty, setUnboundProperty, toArray, toArray

Methods inherited from class com.bigdata.bop.CoreBaseBOp

annotationsEqual, annotationsToString, annotationsToString, annotationValueToString, checkArgs, clone, equals, getEvaluationContext, getId, getProperty, getRequiredProperty, hashCode, indent, isController, mutation, shortenName, toShortString, toString, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DistinctTermScanOp

public DistinctTermScanOp(DistinctTermScanOp<E> op)

Deep copy constructor.

Parameters:

op -

DistinctTermScanOp

public DistinctTermScanOp(BOp[] args,
                  Map<String,Object> annotations)

Shallow copy constructor.

Parameters:

args -

annotations -

DistinctTermScanOp

public DistinctTermScanOp(BOp[] args,
                  NV... annotations)

Method Detail

getDistinctVar

protected IVariable<?> getDistinctVar()

See Also:

DistinctTermScanOp.Annotations.DISTINCT_VAR

getSelect

protected IVariable<?>[] getSelect()

See Also:

JoinAnnotations.SELECT

constraints

protected IConstraint[] constraints()

See Also:

JoinAnnotations.CONSTRAINTS

getPredicate

public IPredicate<E> getPredicate()

eval

public FutureTask<Void> eval(BOpContext<IBindingSet> context)

Description copied from class: PipelineOp

Return a FutureTask which computes the operator against the evaluation context. The caller is responsible for executing the FutureTask (this gives them the ability to hook the completion of the computation).

Specified by:

eval in class PipelineOp

Parameters:

context - The evaluation context.

Returns:

The FutureTask which will compute the operator's evaluation.