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

Class Quantifier

java.lang.Object

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

All Implemented Interfaces:

Bindable

Direct Known Subclasses:

Quantifier.Existential, Quantifier.ForEach, Quantifier.Physical

public abstract class Quantifier
extends Object
implements Bindable

Models the concept of quantification.

A quantifier describes the data flow between the output of one RelationalExpression R and the consumption of that data by another RelationalExpression S. S is said to own the quantifier, while the quantifier is said to range over R. Quantifiers come in very few but very distinct flavors. All flavors are implemented by static inner final classes in order to emulate a sealed trait.

Quantifiers separate what it means to be producing versus consuming items. The expression a quantifier ranges over produces records, the quantifier flows information (in a manner determined by the flavor) that is consumed by the expression containing or owning the quantifier. That expression can consume the data in a way independent of how the data was produced in the first place.

A quantifier works closely with the expression that owns it. Depending on the semantics of the owning expression it becomes possible to model correlations. For example, in a logical join expression the quantifier can provide a binding of the item being currently consumed by the join's outer to other (inner) parts of the data flow that are also rooted at the owning (join) expression.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Quantifier.Existential	A quantifier that conceptually flows exactly one item containing a boolean to the owning expression indicating whether the subgraph that the quantifier ranges over produced a non-empty or an empty result.
static class	Quantifier.ForEach	A quantifier that conceptually flows one item at a time from the expression it ranges over to the owning expression.
static class	Quantifier.Physical	Physical quantifier.

Constructor Summary

Constructors

Constructor	Description
Quantifier()

Method Summary

Modifier and Type	Method	Description
<U> U	acceptPropertyVisitor(PlannerProperty<U> visitor)	Allow the computation of PlannerPropertys across the quantifiers in the data flow graph.
Stream<PlannerBindings>	bindTo(ExpressionMatcher<? extends Bindable> matcher)	Attempt to match the matcher to this bindable object.
boolean	equals(Object o)
static Quantifier.Existential	existential(ExpressionRef<? extends RelationalExpression> rangesOver)	Factory method to create an existential quantifier over a given expression reference containing relational expressions.
static Quantifier.ForEach	forEach(ExpressionRef<? extends RelationalExpression> rangesOver)	Factory method to create a for-each quantifier over a given expression reference containing relational expressions.
abstract ExpressionRef<? extends RelationalExpression>	getRangesOver()	Return the reference that the quantifier ranges over.
abstract String	getShorthand()	Return a short hand string for the quantifier.
int	hashCode()
static Quantifier.Physical	physical(RecordQueryPlan rangesOverPlan)	Factory method to create a physical quantifier over newly created expression reference containing the given record plan.
static Quantifier.Physical	physical(ExpressionRef<? extends RecordQueryPlan> rangesOver)	Factory method to create a physical quantifier over a given expression reference containing query plans.

Methods inherited from class java.lang.Object

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

Constructor Detail

Quantifier

public Quantifier()

Method Detail

forEach

@Nonnull
public static Quantifier.ForEach forEach(ExpressionRef<? extends RelationalExpression> rangesOver)

Factory method to create a for-each quantifier over a given expression reference containing relational expressions.

Parameters:

rangesOver - expression reference to RelationalExpressions

Returns:

a for-each quantifier ranging over the given expression reference

existential

@Nonnull
public static Quantifier.Existential existential(@Nonnull
                                                 ExpressionRef<? extends RelationalExpression> rangesOver)

Factory method to create an existential quantifier over a given expression reference containing relational expressions.

Parameters:

rangesOver - expression reference to RelationalExpressions

Returns:

a for-each quantifier ranging over the given expression reference

physical

@Nonnull
public static Quantifier.Physical physical(@Nonnull
                                           ExpressionRef<? extends RecordQueryPlan> rangesOver)

Factory method to create a physical quantifier over a given expression reference containing query plans.

Parameters:

rangesOver - expression reference to RecordQueryPlans

Returns:

a physical quantifier ranging over the given reference

physical

@Nonnull
public static Quantifier.Physical physical(@Nonnull
                                           RecordQueryPlan rangesOverPlan)

Factory method to create a physical quantifier over newly created expression reference containing the given record plan.

Parameters:

rangesOverPlan - RecordQueryPlan the new quantifier should range over.

Returns:

a physical quantifier ranging over a new expression reference containing the given expression reference

getRangesOver

@Nonnull
public abstract ExpressionRef<? extends RelationalExpression> getRangesOver()

Return the reference that the quantifier ranges over.

Returns:

ExpressionRef this quantifier ranges over

getShorthand

@Nonnull
public abstract String getShorthand()

Return a short hand string for the quantifier. As a quantifier's semantics is usually quite subtle and should not distract from expressions. For example, when a data flow is visualized the returned string should be short.

Returns:

a short string representing the quantifier.

bindTo

@Nonnull
public Stream<PlannerBindings> bindTo(@Nonnull
                                      ExpressionMatcher<? extends Bindable> matcher)

Description copied from interface: Bindable

Attempt to match the matcher to this bindable object.

Specified by:

bindTo in interface Bindable

Parameters:

matcher - the matcher to match against

Returns:

a map of bindings if the match succeeded, or an empty Optional if it failed

acceptPropertyVisitor

@Nullable
public <U> U acceptPropertyVisitor(@Nonnull
                                   PlannerProperty<U> visitor)

Allow the computation of PlannerPropertys across the quantifiers in the data flow graph.

Type Parameters:

U - the type of the property being computed

Parameters:

visitor - the planner property that is being computed

Returns:

the property

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object