@Documented @Retention(value=RUNTIME) @Target(value=ANNOTATION_TYPE) public @interface TargetLocations
A meta-annotation that restricts the type-use locations where a type qualifier may be written.
When written together with @Target({ElementType.TYPE_USE}), the given type qualifier may
be written only at locations listed in the @TargetLocations(...) meta-annotation.
@Target({ElementType.TYPE_USE}) together with no @TargetLocations(...) means that
the qualifier can be written on any type use.
This enables a type system designer to permit a qualifier to be written only in certain
locations. For example, some type systems' top and bottom qualifier (such as KeyForBottom) should only be written on an explicit
wildcard upper or lower bound. This meta-annotation is a declarative, coarse-grained approach to
enable that. For finer-grained control, override visit* methods that visit trees in
BaseTypeVisitor.
This annotation does not prevent the type system from defaulting, inferring, or computing the given type annotation at the given location. It only prevents users from writing an explicit annotation at the given location.
| Modifier and Type | Required Element and Description |
|---|---|
TypeUseLocation[] |
value
Type uses at which the qualifier is permitted to be written in source code.
|
public abstract TypeUseLocation[] value