Package org.checkerframework.checker.initialization.qual

Annotation Interface UnknownInitialization

@Documented @Retention(RUNTIME) @Target({TYPE_USE,TYPE_PARAMETER}) @SubtypeOf({}) @DefaultFor({LOCAL_VARIABLE,RESOURCE_VARIABLE}) public @interface UnknownInitialization
This type qualifier indicates how much of an object has been fully initialized. An object is fully initialized when each of its fields contains a value that satisfies the field's declaration.

An expression of type @UnknownInitialization(T.class) refers to an object that has all fields of T (and any super-classes) initialized. Just @UnknownInitialization is equivalent to @UnknownInitialization(Object.class).

A common use is 


 void myMethod(@UnknownInitialization(MyClass.class) MyClass this, ...) { ... }
which allows myMethod to be called from the MyClass constructor. See the manual for more examples of how to use the annotation (the link appears below).

Reading a field of an object of type @UnknownInitialization might yield a value that does not correspond to the declared type qualifier for that field. For instance, consider a non-null field: 

@NonNull Object f;
In a partially-initialized object, field f might be null despite its @NonNull type annotation.

What type qualifiers on the field are considered depends on the checker; for instance, the NullnessChecker considers NonNull. The initialization type system is not used on its own, but in conjunction with some other type-system that wants to ensure safe initialization.

See the Checker Framework Manual:
Initialization Checker

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    Class<?>
    value
    The type-frame down to which the expression (of this type) has been initialized at least (inclusive).

  • Element Details

    • value

      Class<?> value
      The type-frame down to which the expression (of this type) has been initialized at least (inclusive). That is, an expression of type @UnknownInitialization(T.class) has all type-frames initialized starting at Object down to (and including) T.
      Returns:
      the type whose fields are fully initialized
      Default:
      java.lang.Object.class