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

Class VersionElement

  • All Implemented Interfaces:
    PlanHashable, Element
    public class VersionElement
extends Object
implements Element
    An Element representing a serialized versionstamp in a query or index entry. Since versions are associated with individual index entries rather than records per se, a version element does not have a source.

    • Constructor Detail

      • VersionElement

        public VersionElement()

    • 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.
        Specified by:
        matchWith in interface Element
        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.

        Specified by:
        matchSourcesWith in interface Element
        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

      • getAncestralSources

        @Nonnull
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

      • 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.
        Specified by:
        withSourceMappedInto in interface Element
        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.
        Specified by:
        eval in interface Element
        Parameters:
        sourceEntry - a source entry to use when evaluating this element
        Returns:
        the value of this element on the given source entry

      • 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.
        Specified by:
        planHash in interface PlanHashable
        Returns:
        a stable hash code