Package com.apple.foundationdb.record.query.plan.temp.matchers

Class MultiChildrenMatcher

java.lang.Object

com.apple.foundationdb.record.query.plan.temp.matchers.MultiChildrenMatcher

All Implemented Interfaces:

ExpressionChildrenMatcher

Direct Known Subclasses:

MultiChildrenMatcher.AllChildrenMatcher, MultiChildrenMatcher.SomeChildrenMatcher

@API(EXPERIMENTAL)
public abstract class MultiChildrenMatcher
extends Object
implements ExpressionChildrenMatcher

An expression children matcher that tries to match a multitude of children to a single ExpressionMatcher.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	MultiChildrenMatcher.AllChildrenMatcher	An expression children matcher that tries to match all children to a single ExpressionMatcher.
static class	MultiChildrenMatcher.SomeChildrenMatcher	An expression children matcher that tries to match some children to a single ExpressionMatcher.

Method Summary

Modifier and Type	Method	Description
static MultiChildrenMatcher	allMatching(ExpressionMatcher<? extends Bindable> childMatcher)	Get a matcher that tries to match all children with the given ExpressionMatcher.
Stream<PlannerBindings>	matches(PlannerBindings outerBindings, List<? extends Bindable> children)	Apply this matcher to the children provided by the given iterator and produce a stream of possible bindings.
protected abstract Optional<Stream<PlannerBindings>>	onEmptyIndividualBindings(Stream<PlannerBindings> accumulatedStream)
static MultiChildrenMatcher	someMatching(ExpressionMatcher<? extends Bindable> childMatcher)	Get a matcher that tries to match some children with the given ExpressionMatcher.

Methods inherited from class java.lang.Object

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

Method Detail

matches

@Nonnull
public Stream<PlannerBindings> matches(@Nonnull
                                       PlannerBindings outerBindings,
                                       @Nonnull
                                       List<? extends Bindable> children)

Description copied from interface: ExpressionChildrenMatcher

Apply this matcher to the children provided by the given iterator and produce a stream of possible bindings. If the match is not successful, produce an empty stream. Note that this method should not generally match to the children themselves; instead, it should delegate that work to one or more inner ExpressionMatchers.

Specified by:

matches in interface ExpressionChildrenMatcher

Parameters:

outerBindings - preexisting bindings supplied by the caller

children - a list of references to the children of a planner expression

Returns:

a stream of the possible bindings from applying this match to the children in the given iterator

onEmptyIndividualBindings

@Nonnull
protected abstract Optional<Stream<PlannerBindings>> onEmptyIndividualBindings(@Nonnull
                                                                               Stream<PlannerBindings> accumulatedStream)

allMatching

@Nonnull
public static MultiChildrenMatcher allMatching(@Nonnull
                                               ExpressionMatcher<? extends Bindable> childMatcher)

Get a matcher that tries to match all children with the given ExpressionMatcher.

Parameters:

childMatcher - an expression matcher to match all of the children

Returns:

a matcher that tries to match all children with the given child matcher

someMatching

@Nonnull
public static MultiChildrenMatcher someMatching(@Nonnull
                                                ExpressionMatcher<? extends Bindable> childMatcher)

Get a matcher that tries to match some children with the given ExpressionMatcher.

Parameters:

childMatcher - an expression matcher to match all of the children

Returns:

a matcher that tries to match some children with the given child matcher