org.checkerframework.framework.qual

Annotation Type HasQualifierParameter

@Documented
 @Retention(value=RUNTIME)
 @Target(value={TYPE,PACKAGE})
public @interface HasQualifierParameter

This is a declaration annotation that applies to type declarations and packages. On a type, it means that the class conceptually takes a type qualifier parameter, though there is nowhere to write it because the class hard-codes a Java basetype rather than taking a type parameter. Writing HasQualifierParameter on a package is the same as writing it on each class in that package.

Writing @HasQualifierParameter on a type declaration has two effects.

1. Invariant subtyping is used for occurrences of the type: no two occurrences of the type with different qualifiers have a subtyping relationship.
2. The polymorphic qualifier is the default for all occurrences of that type in its own compilation unit, including as the receiver, as another formal parameter, or as a return type.

Here is an example of the effect of invariant subtyping. Suppose we have the following declaration:

   @HasQualifierParameter
   class StringBuffer { ... }
 

Then @Tainted StringBuffer is unrelated to @Untainted StringBuffer.

The type hierarchy looks like this:

                        @Tainted Object
                      /       |       \
                     /        |        @Tainted Date
                   /          |               |
                  /           |               |
                 /    @Untainted Object       |
                /             |       \       |
   @Tainted StringBuffer      |       @Untainted Date
             |                |
             |       @Untainted StringBuffer
             |                |
   @Tainted MyStringBuffer    |
                              |
                     @Untainted MyStringBuffer
 

This annotation may not be written on the same class as NoQualifierParameter for the same hierarchy.

When @HasQualifierParameter is written on a package, it is equivalent to writing it on each class in that package with the same arguments, including classes in sub-packages. It can be disabled on a specific class by writing @NoQualifierParameter on that class.

See Also:

NoQualifierParameter

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
Class<? extends Annotation>[]	value Class of the top qualifier for the hierarchy for which this class has a qualifier parameter.

Element Detail

value

public abstract Class<? extends Annotation>[] value

Class of the top qualifier for the hierarchy for which this class has a qualifier parameter.

Returns:

the value