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

Interface PlannerRuleCall

  • All Known Implementing Classes:
    CascadesRuleCall
    @API(EXPERIMENTAL)
public interface PlannerRuleCall
    A PlannerRuleCall is a context object that supports a single application of a rule to a particular expression. It stores and provides convenient access to various context related to the transformation, such as any bindings, access to the PlanContext, etc. A PlannerRuleCall is passed to every rule's PlannerRule.onMatch(PlannerRuleCall) method. Additionally, the rule call implementation is responsible for registering any new expressions generated by the rule via the yield(ExpressionRef) method. This registration process includes updating any planner data structures to include the new expression. In general, each planner will have an associated implementation of PlannerRuleCall.

    • Method Detail

      • getBindings

        @Nonnull
PlannerBindings getBindings()
        Return the map of bindings that this rule's matcher expression produced, which includes (by contract) all of the bindings specified by the rule associated with this call. This method should be implemented by rule call implementations, but users of the rule should usually access these via get(ExpressionMatcher).
        Returns:
        the map of bindings that the rule's matcher expression produced

      • getContext

        @Nonnull
PlanContext getContext()
        Get the planning context with metadata that might be relevant to the planner, such as the list of available indexes.
        Returns:
        a PlanContext object with various metadata that could affect planning

      • get

        @Nonnull
default <U extends Bindable> U get​(@Nonnull
                                   ExpressionMatcher<U> key)
        Return the bindable that is bound to the given key.
        Type Parameters:
        U - the requested return type
        Parameters:
        key - the binding from the rule's matcher expression
        Returns:
        the bindable bound to name in the rule's matcher expression
        Throws:
        NoSuchElementException - when key is not a valid binding, or is not bound to a bindable

      • yield

        void yield​(@Nonnull
           ExpressionRef<? extends RelationalExpression> expression)
        Notify the planner's data structures that the new expression contained in expression has been produced by the rule. This method may be called zero or more times by the rule's onMatch() method.
        Parameters:
        expression - the expression produced by the rule

      • ref

        <U extends RelationalExpression> ExpressionRef<U> ref​(U expression)
        Wrap the given planner expression in an implementation of ExpressionRef suitable for the planner associated with this rule. Different rule call implementations might use different reference types depending on the specifics of the associated planner.
        Type Parameters:
        U - the type of the planner expression
        Parameters:
        expression - the planner expression to wrap in a reference type
        Returns:
        expression wrapped in a reference