Void for visitors that do not need to return results.
Void for visitors that do not need an
additional parameter.
accept method, the visitXyz method most applicable
to that element 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,
as done for visitModule and visitRecordComponent. 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
FooVisitorN where N indicates the
source version the
visitor is appropriate for.
In particular, a FooVisitorN 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), FooVisitorN may also handle that later source version; in
that case, the SupportedSourceVersion annotation on the FooVisitorN class will indicate a later version.
When visiting an element representing a language construct
introduced after source version N, a FooVisitorN will throw an UnknownElementException
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:
AbstractElementVisitors:
Skeletal visitor implementations.
SimpleElementVisitors: Support
default actions and a default return value.
ElementKindVisitors: Visit methods
provided on a per-kind granularity as
some categories of elements can have more than one kind.
ElementScanners: Scanners are visitors
which traverse an element and the elements enclosed by it and associated with it.
| Modifier and Type | Method and Description |
|---|---|
| public R | |
| public default R | |
| public R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits an executable element. |
| public default R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits a module element. |
| public R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits a package element. |
| public default R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits a record component element. |
| public R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits a type element. |
| public R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits a type parameter element. |
| public R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits an unknown kind of element. |
| public R | Returns: a visitor-specified resultthe element to visit e, P a visitor-specified parameter p)Visits a variable element. |
| visit | back to summary |
|---|---|
| public R visit(Element e, P p) Visits an element.
| |
| visit | back to summary |
|---|---|
| public default R visit(Element e) A convenience method equivalent to Implementation Specification The default implementation is
| |
| visitExecutable | back to summary |
|---|---|
| public R visitExecutable(ExecutableElement e, P p) Visits an executable element.
| |
| visitModule | back to summary |
|---|---|
| public default R visitModule(ModuleElement e, P p) Visits a module element. Implementation Specification The default implementation visits a
| |
| visitPackage | back to summary |
|---|---|
| public R visitPackage(PackageElement e, P p) Visits a package element.
| |
| visitRecordComponent | back to summary |
|---|---|
| public default R visitRecordComponent(RecordComponentElement e, P p) Visits a record component element. Implementation Specification The default implementation visits a
| |
| visitType | back to summary |
|---|---|
| public R visitType(TypeElement e, P p) Visits a type element.
| |
| visitTypeParameter | back to summary |
|---|---|
| public R visitTypeParameter(TypeParameterElement e, P p) Visits a type parameter element.
| |
| visitUnknown | back to summary |
|---|---|
| public R visitUnknown(Element e, P p) Visits an unknown kind of element.
This can occur if the language evolves and new kinds
of elements are added to the
| |
| visitVariable | back to summary |
|---|---|
| public R visitVariable(VariableElement e, P p) Visits a variable element.
| |