- Type Parameters:
R
- the return type of this visitor's methods. UseVoid
for visitors that do not need to return results.P
- the type of the additional parameter to this visitor's methods. UseVoid
for visitors that do not need an additional parameter.
- All Known Implementing Classes:
AbstractTypeVisitor14
,AbstractTypeVisitor6
,AbstractTypeVisitor7
,AbstractTypeVisitor8
,AbstractTypeVisitor9
,SimpleTypeVisitor14
,SimpleTypeVisitor6
,SimpleTypeVisitor7
,SimpleTypeVisitor8
,SimpleTypeVisitor9
,TypeKindVisitor14
,TypeKindVisitor6
,TypeKindVisitor7
,TypeKindVisitor8
,TypeKindVisitor9
accept
method, the visitXyz
method most applicable to that type is invoked.
Classes implementing this interface may or may not throw a
NullPointerException
if the additional parameter p
is null
; see documentation of the implementing class for
details.
- API Note:
- WARNING: It is possible that methods will be added
to this interface to accommodate new, currently unknown, language
structures added to future versions of the Java programming
language.
Such additions have already occurred to support language features
added after this API was introduced.
Visitor classes directly implementing this interface may be source
incompatible with future versions of the platform. To avoid this
source incompatibility, visitor implementations are encouraged to
instead extend the appropriate abstract visitor class that
implements this interface. However, an API should generally use
this visitor interface as the type for parameters, return type,
etc. rather than one of the abstract classes.
Methods to accommodate new language constructs are expected to be added as default methods to provide strong source compatibility. The implementations of the default methods will in turn call
visitUnknown
, behavior that will be overridden in concrete visitors supporting the source version with the new language construct.There are several families of classes implementing this visitor interface in the util package. The families follow a naming pattern along the lines of
FooVisitor
N where N indicates the source version the visitor is appropriate for. In particular, aFooVisitor
N is expected to handle all language constructs present in source version N. If there are no new language constructs added in version N + 1 (or subsequent releases),FooVisitor
N may also handle that later source version; in that case, theSupportedSourceVersion
annotation on theFooVisitor
N class will indicate a later version. When visiting a type representing a language construct introduced after source version N, aFooVisitor
N will throw anUnknownTypeException
unless that behavior is overridden.When choosing which member of a visitor family to subclass, subclassing the most recent one increases the range of source versions covered. When choosing which visitor family to subclass, consider their built-in capabilities:
AbstractTypeVisitor
s: Skeletal visitor implementations.SimpleTypeVisitor
s: Support default actions and a default return value.TypeKindVisitor
s: Visit methods provided on a per-kind granularity as some categories of types can have more than one kind.
- Since:
- 1.6
-
Method Summary
Modifier and TypeMethodDescriptiondefault R
visit
(TypeMirror t) A convenience method equivalent tovisit(t, null)
.visit
(TypeMirror t, P p) Visits a type.visitArray
(ArrayType t, P p) Visits an array type.visitDeclared
(DeclaredType t, P p) Visits a declared type.visitError
(ErrorType t, P p) Visits an error type.visitExecutable
(ExecutableType t, P p) Visits an executable type.Visits an intersection type.visitNoType
(NoType t, P p) Visits aNoType
instance.Visits the null type.visitPrimitive
(PrimitiveType t, P p) Visits a primitive type.visitTypeVariable
(TypeVariable t, P p) Visits a type variable.visitUnion
(UnionType t, P p) Visits a union type.visitUnknown
(TypeMirror t, P p) Visits an unknown kind of type.visitWildcard
(WildcardType t, P p) Visits a wildcard type.
-
Method Details
-
visit
Visits a type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visit
A convenience method equivalent tovisit(t, null)
.- Implementation Requirements:
- The default implementation is
visit(t, null)
. - Parameters:
t
- the element to visit- Returns:
- a visitor-specified result
-
visitPrimitive
Visits a primitive type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitNull
Visits the null type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitArray
Visits an array type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitDeclared
Visits a declared type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitError
Visits an error type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitTypeVariable
Visits a type variable.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitWildcard
Visits a wildcard type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitExecutable
Visits an executable type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitNoType
Visits aNoType
instance.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
-
visitUnknown
Visits an unknown kind of type. This can occur if the language evolves and new kinds of types are added to theTypeMirror
hierarchy.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
- Throws:
UnknownTypeException
- a visitor implementation may optionally throw this exception
-
visitUnion
Visits a union type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
- Since:
- 1.7
-
visitIntersection
Visits an intersection type.- Parameters:
t
- the type to visitp
- a visitor-specified parameter- Returns:
- a visitor-specified result
- Since:
- 1.8
-