Package org.checkerframework.framework.qual

Annotation Interface ConditionalPostconditionAnnotation

@Documented
@Retention(RUNTIME)
@Target(ANNOTATION_TYPE)
public @interface ConditionalPostconditionAnnotation

A meta-annotation that indicates that an annotation E is a conditional postcondition annotation, i.e., E is a type-specialized version of EnsuresQualifierIf or EnsuresQualifierIf.List.

• If E is a type-specialized version of EnsuresQualifierIf, it must have
  • an element expression that is an array of Strings, analogous to EnsuresQualifierIf.expression(), and
  • an element result with the same meaning as EnsuresQualifierIf.result().
• If E is a type-specialized version of EnsuresQualifierIf.List, it must have an element value that is an array of conditional postcondition annotations, analogous to EnsuresQualifierIf.List.value().

The established postcondition P has type specified by the qualifier field of this annotation. If the annotation E has elements annotated by QualifierArgument, their values are copied to the arguments (elements) of annotation P with the same names. Different element names may be used in E and P, if a QualifierArgument in E gives the name of the corresponding element in P.

For example, the following code declares a postcondition annotation for the MinLen qualifier:

 @ConditionalPostconditionAnnotation(qualifier = MinLen.class)
 @Target({ElementType.METHOD, ElementType.CONSTRUCTOR})
 public @interface EnsuresMinLen {
   String[] expression();
   boolean result();
   @QualifierArgument("value")
   int targetValue() default 0;
 

The expression element holds the expressions to which the qualifier applies and targetValue holds the value for the value argument of MinLen.

The following code then uses the annotation on a method that ensures field to be @MinLen(4) upon returning true.

 @EnsuresMinLenIf(expression = "field", result = true, targetValue = 4")
 public boolean isFieldBool() {
   return field == "true" || field == "false";
 }
 

See Also:

• EnsuresQualifier
• QualifierArgument

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
Class<? extends Annotation>	qualifier	The qualifier that will be established as a postcondition.

Element Details

qualifier

Class<? extends Annotation> qualifier

The qualifier that will be established as a postcondition.

This element is analogous to EnsuresQualifierIf.qualifier().