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

Interface KeyExpressionVisitor<S extends KeyExpressionVisitor.State,R extends KeyExpressionVisitor.Result>

Type Parameters:

S - the type of the state object which depends on the specific implementation

R - the type of the result object which is returned by all visitation methods

All Known Subinterfaces:

ExpansionVisitor<S>

All Known Implementing Classes:

PrimaryAccessExpansionVisitor, ValueIndexExpansionVisitor, ValueIndexLikeExpansionVisitor

public interface KeyExpressionVisitor<S extends KeyExpressionVisitor.State,R extends KeyExpressionVisitor.Result>

An interface to provide a state-based visitor pattern that can traverse a tree of KeyExpressions.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	KeyExpressionVisitor.Result	Tag interface to capture the result being returned by visitation methods of this visitor.
static interface	KeyExpressionVisitor.State	Tag interface to capture state within this visitor.

Method Summary

Modifier and Type	Method	Description
S	getCurrentState()	Method to return the (immutable) current state.
R	visitExpression(EmptyKeyExpression emptyKeyExpression)	Specific method that is called on EmptyKeyExpressions.
R	visitExpression(FieldKeyExpression fieldKeyExpression)	Specific method that is called on FieldKeyExpressions.
R	visitExpression(KeyExpression keyExpression)	Default method that is called on unknown sub classes of KeyExpression.
R	visitExpression(KeyExpressionWithValue keyExpressionWithValue)	Specific method that is called on KeyExpressionWithValues.
R	visitExpression(KeyWithValueExpression keyWithValueExpression)	Specific method that is called on KeyWithValueExpressions.
R	visitExpression(NestingKeyExpression nestingKeyExpression)	Specific method that is called on NestingKeyExpressions.
R	visitExpression(ThenKeyExpression thenKeyExpression)	Specific method that is called on ThenKeyExpressions.

Method Detail

getCurrentState

S getCurrentState()

Method to return the (immutable) current state.

Returns:

the current state of type S

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  KeyExpression keyExpression)

Default method that is called on unknown sub classes of KeyExpression. That makes it possible to add a visitor.visitExpression(this) regardless whether the visitor defines an actual specific override for the sub class of this or not.

Parameters:

keyExpression - key expression to visit

Returns:

a new expression of type R

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  EmptyKeyExpression emptyKeyExpression)

Specific method that is called on EmptyKeyExpressions.

Parameters:

emptyKeyExpression - EmptyKeyExpression to visit

Returns:

a new expression of type R

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  FieldKeyExpression fieldKeyExpression)

Specific method that is called on FieldKeyExpressions.

Parameters:

fieldKeyExpression - FieldKeyExpression to visit

Returns:

a new expression of type R

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  KeyExpressionWithValue keyExpressionWithValue)

Specific method that is called on KeyExpressionWithValues.

Parameters:

keyExpressionWithValue - KeyExpressionWithValue to visit

Returns:

a new expression of type R

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  KeyWithValueExpression keyWithValueExpression)

Specific method that is called on KeyWithValueExpressions.

Parameters:

keyWithValueExpression - KeyWithValueExpression to visit

Returns:

a new expression of type R

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  NestingKeyExpression nestingKeyExpression)

Specific method that is called on NestingKeyExpressions.

Parameters:

nestingKeyExpression - NestingKeyExpression to visit

Returns:

a new expression of type R

visitExpression

@Nonnull
R visitExpression(@Nonnull
                  ThenKeyExpression thenKeyExpression)

Specific method that is called on ThenKeyExpressions.

Parameters:

thenKeyExpression - ThenKeyExpression to visit

Returns:

a new expression of type R