org.checkerframework.framework.qual

Annotation Type SubtypeOf

@Documented
 @Retention(value=RUNTIME)
 @Target(value=ANNOTATION_TYPE)
 @AnnotatedFor(value="nullness")
public @interface SubtypeOf

A meta-annotation to specify all the qualifiers that the given qualifier is an immediate subtype of. This provides a declarative way to specify the type qualifier hierarchy. (Alternatively, the hierarchy can be defined procedurally by subclassing QualifierHierarchy or TypeHierarchy.)

Example:

 @SubtypeOf( { Nullable.class } )
 public @interface NonNull {}
 

For the top qualifier in the qualifier hierarchy (i.e., the qualifier that is a supertype of all other qualifiers in the given hierarchy), use an empty set of values:

 @SubtypeOf( {} )
 public @interface Nullable {}

 @SubtypeOf( {} )
 public @interface MaybeAliased {}
 

Together, all the @SubtypeOf meta-annotations fully describe the type qualifier hierarchy.

See the Checker Framework Manual:

Declaratively defining the qualifier hierarchy

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
Class<? extends Annotation>[]	value An array of the supertype qualifiers of the annotated qualifier.

Element Detail

value

public abstract Class<? extends Annotation>[] value

An array of the supertype qualifiers of the annotated qualifier.