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

Class ExpressionRefTraversal

java.lang.Object

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

@API(EXPERIMENTAL)
public class ExpressionRefTraversal
extends Object

Utility class to provide a graph view of a expression reference DAG given by a root expression reference (to a RelationalExpression that allows to perform traversal operations that are normally not possible on instances of ExpressionRef such as getLeafReferences() and getParentRefs(com.apple.foundationdb.record.query.plan.temp.ExpressionRef<? extends com.apple.foundationdb.record.query.plan.temp.RelationalExpression>). The implementation of this class assumes that the original DAG is not mutated after the traversal is created. If the underlying DAG is mutated against assumptions, the semantics of this class is defined in a way that calls to graph-backed methods return data as if the mutation hadn't occurred while references that are being returned as part of the result of method calls naturally reflect any mutations that have occurred.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ExpressionRefTraversal.ReferencePath	Case class to hold information about the path from an expression to another expression reference.

Method Summary

Modifier and Type	Method	Description
void	addExpression(ExpressionRef<? extends RelationalExpression> reference, RelationalExpression expression)
void	forEachParentExpression(ExpressionRef<? extends RelationalExpression> reference, BiConsumer<ExpressionRef<? extends RelationalExpression>,RelationalExpression> biConsumer)
Set<ExpressionRef<? extends RelationalExpression>>	getLeafReferences()
Set<RelationalExpression>	getParentExpressions(ExpressionRef<? extends RelationalExpression> reference)	Return all expressions (as RelationalExpressions) that refer to this expression reference
Set<ExpressionRefTraversal.ReferencePath>	getParentRefPaths(ExpressionRef<? extends RelationalExpression> reference)	Return all expressions (as RelationalExpressions) that refer to this expression reference
Set<ExpressionRef<? extends RelationalExpression>>	getParentRefs(ExpressionRef<? extends RelationalExpression> reference)	Return all expression references that contain a path from parent -> expression -> quantifier -> this reference
Set<ExpressionRef<? extends RelationalExpression>>	getRefs()
Set<ExpressionRef<? extends RelationalExpression>>	getRefsContaining(RelationalExpression expression)	Returns all references containing the expression passed in.
ExpressionRef<? extends RelationalExpression>	getRootReference()
static ExpressionRefTraversal	withRoot(ExpressionRef<? extends RelationalExpression> rootRef)	Construct a traversal object using the rootRef reference passed in.

Methods inherited from class java.lang.Object

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

Method Detail

getRootReference

@Nonnull
public ExpressionRef<? extends RelationalExpression> getRootReference()

getRefs

@Nonnull
public Set<ExpressionRef<? extends RelationalExpression>> getRefs()

getLeafReferences

@Nonnull
public Set<ExpressionRef<? extends RelationalExpression>> getLeafReferences()

getRefsContaining

public Set<ExpressionRef<? extends RelationalExpression>> getRefsContaining(RelationalExpression expression)

Returns all references containing the expression passed in.

Parameters:

expression - the expression

Returns:

a set of expression references containing expression

getParentRefs

@Nonnull
public Set<ExpressionRef<? extends RelationalExpression>> getParentRefs(@Nonnull
                                                                        ExpressionRef<? extends RelationalExpression> reference)

Return all expression references that contain a path from parent -> expression -> quantifier -> this reference

Parameters:

reference - reference

Returns:

the set of references that are considered parents of this reference.

getParentExpressions

@Nonnull
public Set<RelationalExpression> getParentExpressions(@Nonnull
                                                      ExpressionRef<? extends RelationalExpression> reference)

Return all expressions (as RelationalExpressions) that refer to this expression reference

Parameters:

reference - reference

Returns:

the set of expressions (as identity-based set) that are considered parents of this reference.

getParentRefPaths

@Nonnull
public Set<ExpressionRefTraversal.ReferencePath> getParentRefPaths(@Nonnull
                                                                   ExpressionRef<? extends RelationalExpression> reference)

Return all expressions (as RelationalExpressions) that refer to this expression reference

Parameters:

reference - reference to return the parent reference paths for

Returns:

the set of expressions that are considered parents of this reference.

forEachParentExpression

public void forEachParentExpression(@Nonnull
                                    ExpressionRef<? extends RelationalExpression> reference,
                                    @Nonnull
                                    BiConsumer<ExpressionRef<? extends RelationalExpression>,RelationalExpression> biConsumer)

addExpression

public void addExpression(ExpressionRef<? extends RelationalExpression> reference,
                          RelationalExpression expression)

withRoot

public static ExpressionRefTraversal withRoot(ExpressionRef<? extends RelationalExpression> rootRef)

Construct a traversal object using the rootRef reference passed in.

Parameters:

rootRef - the reference acting as the root for this traversal object

Returns:

a new traversal object