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

A package for planner properties (in the sense that Cascades uses them).

In Cascades, a property is an attribute of RelationalExpression that cannot be described from the structure of the expression tree alone. For example, the set of record types that a relational planner expression produces is a property, but whether or not it has a filter that contains an AND clause is not a property. Properties generally need to be evaluated against an expression, instead of arising from the structural features of a planner expression (which could be matched using an ExpressionMatcher.

In the Record Layer, properties are implemented as hierarchical visitors on the PlannerExpression tree; this approach prevents the accumulation of many methods on the PlannerExpression interface. Furthermore, some properties (such as the set of possible record types returned) cannot be determined from the PlannerExpression alone; they also need access to the PlanContext.

This package contains various implementations of PlannerProperty.

Class Summary

Class	Description
CreatesDuplicatesProperty	A property that determines whether the expression may produce duplicate entries.
ExpressionCountProperty	A property that determines the sum, over all elements of a PlannerExpression tree, of the number of occurrences of specific types of RelationalExpression.
FieldWithComparisonCountProperty	A property that counts the number of FieldWithComparisons that appear in a planner expression tree.
OrderingProperty	A property that determines whether the expression may produce duplicate entries.
OrderingProperty.OrderingInfo	Class to hold the info returned by this property.
PredicateCountProperty	A property that counts the number of ValuePredicates that appear in a planner expression tree.
RecordTypesProperty	A property visitor that determines the set of record type names (as Strings) that a RelationalExpression could produce.
RelationalExpressionDepthProperty	A property representing the minimum depth of any of a set of relational planner expression types in a relational planner expression: that is, the smallest integer such that one of those types is exactly that many relational planner expressions away from the root expression.
TypeFilterCountProperty	A property that determines the sum, over all elements of a PlannerExpression tree, of the number of record types that are passed by type filters in the tree.
UnmatchedFieldsProperty	A property for counting the total number of KeyExpression columns (i.e., field-like KeyExpressions such as FieldKeyExpression and RecordTypeKeyExpression) that are not matched with at least one Comparisons.Comparison in a planner expression tree.