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

Class ValueElement

java.lang.Object

com.apple.foundationdb.record.query.plan.temp.view.ValueElement

All Implemented Interfaces:

PlanHashable, Element

@API(EXPERIMENTAL)
public class ValueElement
extends Object

An Element representing an entire value, such as a scalar or message, obtained from a source.

For example, the integer values from a RepeatedFieldSource on a record's repeated integer field would be represented by a ValueElement.

Field Summary

Fields

Modifier and Type	Field	Description
protected Source	source

Constructor Summary

Constructors

Constructor	Description
ValueElement(Source source)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
Object	eval(SourceEntry sourceEntry)	Evaluate this element with respect to the given source entry, producing an object that can be interpreted by a Comparisons.Comparison.
Set<Source>	getAncestralSources()	Get the set of all sources for this element, including all ancestors of this element's sources.
Source	getSource()
int	hashCode()
Optional<ViewExpressionComparisons>	matchSourcesWith(ViewExpressionComparisons viewExpressionComparisons, Element element)	Determine whether this element is the same as the given Element when unused sources are combined with each other.
Optional<ComparisonRange>	matchWith(ComparisonRange existingComparisons, ElementPredicate predicate)	Determine whether this element can be used to satisfy the given ElementPredicate, under the assumption that this element is already being used to satisfy the given ComparisonRange.
int	planHash()	Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.
String	toString()
Element	withSourceMappedInto(Source originalSource, Source duplicateSource)	Replace the given duplicate source with the given original source everywhere that it occurs in this element, including in ancestor sources of this element's source.

Methods inherited from class java.lang.Object

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

Field Detail

source

@Nonnull
protected final Source source

Constructor Detail

ValueElement

public ValueElement(@Nonnull
                    Source source)

Method Detail

matchWith

@Nonnull
public Optional<ComparisonRange> matchWith(@Nonnull
                                           ComparisonRange existingComparisons,
                                           @Nonnull
                                           ElementPredicate predicate)

Description copied from interface: Element

Determine whether this element can be used to satisfy the given ElementPredicate, under the assumption that this element is already being used to satisfy the given ComparisonRange. Note that this method relies on strict comparisons between elements, i.e., the sources must be reference-equal to each other.

Parameters:

existingComparisons - a range of existing comparisons that the planner is using this element to support

predicate - an element predicate to match with this element and the given comparison range

Returns:

a new comparison range incorporating the predicate's comparison if the match was successful, Optional.empty() otherwise

matchSourcesWith

@Nonnull
public Optional<ViewExpressionComparisons> matchSourcesWith(@Nonnull
                                                            ViewExpressionComparisons viewExpressionComparisons,
                                                            @Nonnull
                                                            Element element)

Description copied from interface: Element

Determine whether this element is the same as the given Element when unused sources are combined with each other. Sources are determined to be used or unused based on their usage in the given ViewExpressionComparisons. A source is used if any element using that source has a comparison already matched to it; otherwise, it is unused. If an available match is found, produce a version of the given ViewExpressionComparisons with all instances of this element's source replaced with the given element's source.

This method makes it possible to match ElementPredicates generated by normalizing a QueryComponent with those generated by normalizing a KeyExpression. These normalization processes are decoupled so the sources for each will not match in general; therefore, Element.matchWith(ComparisonRange, ElementPredicate) will fail to notice when an index defined by a KeyExpression can support a predicate.

Parameters:

viewExpressionComparisons - view expression comparisons that determine which sources are used and unused

element - an element to compare with this one and look for matches made through combining sources

Returns:

a new view expression comparisons with instances of this element's source replaced with the given element's if a match is found, Optional.empty() otherwise

withSourceMappedInto

@Nonnull
public Element withSourceMappedInto(@Nonnull
                                    Source originalSource,
                                    @Nonnull
                                    Source duplicateSource)

Description copied from interface: Element

Replace the given duplicate source with the given original source everywhere that it occurs in this element, including in ancestor sources of this element's source.

Parameters:

originalSource - a source to replace all occurrences of the duplicate source with

duplicateSource - a source to replace with the original source

Returns:

a copy of this element with all occurrences of the duplicate source replaced with the original source

eval

@Nullable
public Object eval(@Nonnull
                   SourceEntry sourceEntry)

Description copied from interface: Element

Evaluate this element with respect to the given source entry, producing an object that can be interpreted by a Comparisons.Comparison.

Parameters:

sourceEntry - a source entry to use when evaluating this element

Returns:

the value of this element on the given source entry

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

planHash

public int planHash()

Description copied from interface: PlanHashable

Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.

Returns:

a stable hash code

getSource

@Nonnull
public Source getSource()

getAncestralSources

public Set<Source> getAncestralSources()

Description copied from interface: Element

Get the set of all sources for this element, including all ancestors of this element's sources.

Specified by:

getAncestralSources in interface Element

Returns:

a set of the sources of all (inclusive) ancestors of this element's sources