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

Class MatchLeafRule

java.lang.Object

com.apple.foundationdb.record.query.plan.temp.PlannerRule<RelationalExpression>

com.apple.foundationdb.record.query.plan.temp.rules.MatchLeafRule

@API(EXPERIMENTAL)
public class MatchLeafRule
extends PlannerRule<RelationalExpression>

Expression-based transformation rule that matches any leaf expression. The rule creates matches of type PartialMatch for any match between this expression and a leaf expression in a MatchCandidate. It seeds the memoization structure for partial matches that is kept as part of ExpressionRef. It prepares further rules such as MatchIntermediateRule and AdjustMatchRule.

Constructor Summary

Constructors

Constructor	Description
MatchLeafRule()

Method Summary

Modifier and Type	Method	Description
Optional<Class<? extends Bindable>>	getRootOperator()	Note: Transformation rules for expressions are partitioned by the class of the root matcher.
void	onMatch(PlannerRuleCall call)

Methods inherited from class com.apple.foundationdb.record.query.plan.temp.PlannerRule

getMatcher, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

MatchLeafRule

public MatchLeafRule()

Method Detail

getRootOperator

public Optional<Class<? extends Bindable>> getRootOperator()

Note: Transformation rules for expressions are partitioned by the class of the root matcher. This does not work here as this rule is non-specific which means that it matches sub classes of RelationalExpression and not just RelationalExpression itself. In order for this rule to fall into the set of rules that is always utilized we return Optional.empty() here.

Overrides:

getRootOperator in class PlannerRule<RelationalExpression>

Returns:

Optional.empty()

See Also:

PlannerRuleSet

onMatch

public void onMatch(@Nonnull
                    PlannerRuleCall call)

Specified by:

onMatch in class PlannerRule<RelationalExpression>