Package groovy.contracts

Annotation Type Requires

@Retention(RUNTIME) @Target({CONSTRUCTOR,METHOD}) @Incubating @Precondition @AnnotationProcessorImplementation(RequiresAnnotationProcessor.class) @Repeatable(RequiresConditions.class) public @interface Requires

Represents a method precondition.

A precondition is a condition that must be met by clients of this class. Whenever the precondition can be satisfied, it is guaranteed that the supplier will fulfil the method's postcondition.

A method's precondition is executed as the first statement within a method call. A successor's precondition weakens the precondition of its parent class, e.g. if A.someMethod declares a precondition and B.someMethod overrides the method the preconditions are combined with a boolean OR.

Example: 

   @Requires({ argument1 != argument2 && argument2 >= 0 })
   void someOperation(def argument1, def argument2)  {
     ...
   }

  • Required Element Summary

    Required Elements
    Modifier and Type
    Required Element
    Description
    Class
    value
     

  • Element Details