Class GroupIterator

java.lang.Object

org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration<BindingSet, QueryEvaluationException>

org.eclipse.rdf4j.common.iteration.CloseableIteratorIteration<BindingSet, QueryEvaluationException>

org.eclipse.rdf4j.query.algebra.evaluation.iterator.GroupIterator

All Implemented Interfaces:

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

public class GroupIterator
extends CloseableIteratorIteration<BindingSet, QueryEvaluationException>

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	GroupIterator.AggregatePredicateCollectorSupplier<T extends AggregateCollector, D>	This is to collect together in operation an aggregate function the name of it.
private static class	GroupIterator.AvgAggregate
private class	GroupIterator.AvgCollector
private static class	GroupIterator.ConcatAggregate
private static class	GroupIterator.CountAggregate
private static class	GroupIterator.CountCollector
private class	GroupIterator.DistinctBindingSets
private class	GroupIterator.DistinctValues
private static class	GroupIterator.Entry
private static class	GroupIterator.IntegerCollector
private static class	GroupIterator.MaxAggregate
private class	GroupIterator.MinAggregate
private static class	GroupIterator.QueryStepEvaluator
private static class	GroupIterator.SampleAggregate
private static class	GroupIterator.SampleCollector
private static class	GroupIterator.StringBuilderCollector
private static class	GroupIterator.SumAggregate
private static class	GroupIterator.ValueCollector
private static class	GroupIterator.WildCardCountAggregate

Field Summary

Fields

Modifier and Type	Field	Description
private static final Predicate<BindingSet>	ALWAYS_TRUE_BINDING_SET
private static final Predicate<Value>	ALWAYS_TRUE_VALUE
private static final Supplier<Predicate<Value>>	ALWAYS_TRUE_VALUE_SUPPLIER
private final QueryEvaluationStep	arguments
private final CollectionFactory	cf
private final QueryEvaluationContext	context
private final Group	group
private final BindingSet	parentBindings
private final EvaluationStrategy	strategy
private final ValueFactory	vf

Constructor Summary

Constructors

Constructor	Description
GroupIterator(EvaluationStrategy strategy, Group group, BindingSet parentBindings, long iterationCacheSyncThreshold, QueryEvaluationContext context)	Deprecated.
GroupIterator(EvaluationStrategy strategy, Group group, BindingSet parentBindings, long iterationCacheSyncThreshold, QueryEvaluationContext context, ValueFactory vf, CollectionFactory cf)
GroupIterator(EvaluationStrategy strategy, Group group, BindingSet parentBindings, QueryEvaluationContext context)

Method Summary

Modifier and Type	Method	Description
private Collection<GroupIterator.Entry>	buildEntries(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)
private GroupIterator.AggregatePredicateCollectorSupplier<?,?>	create(GroupElem ge, ValueFactory vf)
private Iterator<BindingSet>	createIterator()
private List<GroupIterator.Entry>	emptySolutionSpecialCase(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)
void	handleClose()	Called by AbstractCloseableIteration.close() when it is called for the first time.
boolean	hasNext()	Returns true if the iteration has more elements.
private List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>>	makeAggregates()
private BiConsumer<GroupIterator.Entry, MutableBindingSet>	makeBindSolution(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)
private List<AggregateCollector>	makeCollectors(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)
private BiConsumer<BindingSet, MutableBindingSet>	makeSetAValue(List<Function<BindingSet, Value>> getValues, List<BiConsumer<Value, MutableBindingSet>> setBindings, int i)
private BiConsumer<BindingSet, MutableBindingSet>	makeSetValues(List<Function<BindingSet, Value>> getValues, List<BiConsumer<Value, MutableBindingSet>> setBindings)	Build a single method that sets all values without a loop or lookups during evaluation.
BindingSet	next()	Returns the next element in the iteration.
private GroupIterator.QueryStepEvaluator	precompileArg(AggregateOperator operator)
private boolean	shouldValueComparisonBeStrict()

Methods inherited from class CloseableIteratorIteration

hasIterator, remove, setIterator

Methods inherited from class AbstractCloseableIteration

close, isClosed

Methods inherited from class Object

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

Methods inherited from interface CloseableIteration

stream

Field Details

strategy

private final EvaluationStrategy strategy

parentBindings

private final BindingSet parentBindings

group

private final Group group

context

private final QueryEvaluationContext context

arguments

private final QueryEvaluationStep arguments

vf

private final ValueFactory vf

cf

private final CollectionFactory cf

ALWAYS_TRUE_BINDING_SET

private static final Predicate<BindingSet> ALWAYS_TRUE_BINDING_SET

ALWAYS_TRUE_VALUE

private static final Predicate<Value> ALWAYS_TRUE_VALUE

ALWAYS_TRUE_VALUE_SUPPLIER

private static final Supplier<Predicate<Value>> ALWAYS_TRUE_VALUE_SUPPLIER

Constructor Details

GroupIterator

public GroupIterator(EvaluationStrategy strategy,
 Group group,
 BindingSet parentBindings,
 QueryEvaluationContext context)
              throws QueryEvaluationException

Throws:

QueryEvaluationException

GroupIterator

@Deprecated
public GroupIterator(EvaluationStrategy strategy,
 Group group,
 BindingSet parentBindings,
 long iterationCacheSyncThreshold,
 QueryEvaluationContext context)
              throws QueryEvaluationException

Deprecated.

Throws:

QueryEvaluationException

GroupIterator

public GroupIterator(EvaluationStrategy strategy,
 Group group,
 BindingSet parentBindings,
 long iterationCacheSyncThreshold,
 QueryEvaluationContext context,
 ValueFactory vf,
 CollectionFactory cf)
              throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Details

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 AbstractCloseableIteration<BindingSet, QueryEvaluationException>

Throws:

QueryEvaluationException

hasNext

public boolean hasNext()
                throws QueryEvaluationException

Description copied from interface: Iteration

Returns true if the iteration has more elements. (In other words, returns true if Iteration.next() would return an element rather than throwing a NoSuchElementException.)

Specified by:

hasNext in interface Iteration<BindingSet, QueryEvaluationException>

Overrides:

hasNext in class CloseableIteratorIteration<BindingSet, QueryEvaluationException>

Returns:

true if the iteration has more elements.

Throws:

QueryEvaluationException

next

public BindingSet next()
                throws QueryEvaluationException

Description copied from interface: Iteration

Returns the next element in the iteration.

Specified by:

next in interface Iteration<BindingSet, QueryEvaluationException>

Overrides:

next in class CloseableIteratorIteration<BindingSet, QueryEvaluationException>

Returns:

the next element in the iteration.

Throws:

QueryEvaluationException

createIterator

private Iterator<BindingSet> createIterator()
                                     throws QueryEvaluationException

Throws:

QueryEvaluationException

makeSetValues

private BiConsumer<BindingSet, MutableBindingSet> makeSetValues(List<Function<BindingSet, Value>> getValues,
 List<BiConsumer<Value, MutableBindingSet>> setBindings)

Build a single method that sets all values without a loop or lookups during evaluation.

Parameters:

getValues - the methods to access values in a bindingset

setBindings - the methods to set values in a bindingset

Returns:

a BiConsumer that takes the prototype and sets parts into solution as required

makeSetAValue

private BiConsumer<BindingSet, MutableBindingSet> makeSetAValue(List<Function<BindingSet, Value>> getValues,
 List<BiConsumer<Value, MutableBindingSet>> setBindings,
 int i)

makeBindSolution

private BiConsumer<GroupIterator.Entry, MutableBindingSet> makeBindSolution(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)

makeAggregates

private List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> makeAggregates()

buildEntries

private Collection<GroupIterator.Entry> buildEntries(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)
                                              throws QueryEvaluationException

Throws:

QueryEvaluationException

emptySolutionSpecialCase

private List<GroupIterator.Entry> emptySolutionSpecialCase(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)

makeCollectors

private List<AggregateCollector> makeCollectors(List<GroupIterator.AggregatePredicateCollectorSupplier<?,?>> aggregates)

create

private GroupIterator.AggregatePredicateCollectorSupplier<?,?> create(GroupElem ge,
 ValueFactory vf)
                                                               throws QueryEvaluationException

Throws:

QueryEvaluationException

precompileArg

private GroupIterator.QueryStepEvaluator precompileArg(AggregateOperator operator)

shouldValueComparisonBeStrict

private boolean shouldValueComparisonBeStrict()