R
- the return type of this visitor's methods. Use Void
for visitors that do not need to return results.P
- the type of the additional parameter to this visitor's methods. Use Void
for visitors that do not need an additional parameter.AbstractTypeVisitor14
, AbstractTypeVisitor6
, AbstractTypeVisitor7
, AbstractTypeVisitor8
, AbstractTypeVisitor9
, SimpleTypeVisitor14
, SimpleTypeVisitor6
, SimpleTypeVisitor7
, SimpleTypeVisitor8
, SimpleTypeVisitor9
, TypeKindVisitor14
, TypeKindVisitor6
, TypeKindVisitor7
, TypeKindVisitor8
, TypeKindVisitor9
public interface TypeVisitor<R,P>
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.
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, a FooVisitor
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, the SupportedSourceVersion
annotation on the
FooVisitor
N class will indicate a later version. When visiting a type representing a language construct introduced after source version N, a
FooVisitor
N will throw an UnknownTypeException
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. Modifier and Type | Method | Description |
---|---|---|
default R |
visit |
A convenience method equivalent to visit(t, null) . |
R |
visit |
Visits a type. |
R |
visitArray |
Visits an array type. |
R |
visitDeclared |
Visits a declared type. |
R |
visitError |
Visits an error type. |
R |
visitExecutable |
Visits an executable type. |
R |
visitIntersection |
Visits an intersection type. |
R |
visitNoType |
Visits a NoType instance. |
R |
visitNull |
Visits the null type. |
R |
visitPrimitive |
Visits a primitive type. |
R |
visitTypeVariable |
Visits a type variable. |
R |
visitUnion |
Visits a union type. |
R |
visitUnknown |
Visits an unknown kind of type. |
R |
visitWildcard |
Visits a wildcard type. |
R visit(TypeMirror t, P p)
t
- the type to visitp
- a visitor-specified parameterdefault R visit(TypeMirror t)
visit(t, null)
.visit(t, null)
.t
- the element to visitR visitPrimitive(PrimitiveType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitNull(NullType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitArray(ArrayType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitDeclared(DeclaredType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitError(ErrorType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitTypeVariable(TypeVariable t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitWildcard(WildcardType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitExecutable(ExecutableType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitNoType(NoType t, P p)
NoType
instance.t
- the type to visitp
- a visitor-specified parameterR visitUnknown(TypeMirror t, P p)
TypeMirror
hierarchy.t
- the type to visitp
- a visitor-specified parameterUnknownTypeException
- a visitor implementation may optionally throw this exceptionR visitUnion(UnionType t, P p)
t
- the type to visitp
- a visitor-specified parameterR visitIntersection(IntersectionType t, P p)
t
- the type to visitp
- a visitor-specified parameter
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.compiler/javax/lang/model/type/TypeVisitor.html