org.checkerframework.checker.igj.qual

Annotation Type I

@SubtypeOf(value=ReadOnly.class)
 @Documented
 @Retention(value=RUNTIME)
 @Target(value={TYPE_USE,TYPE_PARAMETER})
public @interface I

Template annotation over IGJ Immutability annotations. It acts somewhat similar to Type Variables in Generics. The annotation value is used to distinguish between multiple instances of @I.

Usage on classes

A class annotated with I could be declared with any IGJ Immutability annotation. The actual immutability that @I is resolved dictates the immutability type for all the non-static appearances of @I with the same value as the class declaration.

Example:

     @I
     public class FileDiscriptor {
        private @Immutable Date creationData;
        private @I Date lastModData;

        public @I getLastModDate() @ReadOnly { }
     }

     ...
     void useFileDiscriptor() {
        @Mutable FileDiscriptor file =
                          new @Mutable FileDiscriptor(...);
        ...
        @Mutable Data date = file.getLastModDate();

     }
 

In the last example, @I was resolved to @Mutable for the instance file. Usage on methods

For example, it could be used for method parameters, return values, and the actual IGJ immutability value would be resolved based on the method invocation.

Example:

      static @I Point getMidPoint(@I Point p1, @I Point p2)
          { ...}
 

The method would return a Point object that returns a Point with the same immutability type as the passed parameters if p1 and p2 match in immutability, otherwise @I is resolved to @ReadOnly.

See the Checker Framework Manual:

IGJ Checker

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	value

Element Detail

value

public abstract String value

Default:

"I"