org.checkerframework.framework.qual.PostconditionAnnotation Maven / Gradle / Ivy
package org.checkerframework.framework.qual;
import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* A meta-annotation that indicates that an annotation E is a postcondition annotation, i.e., E is a
* type-specialized version of {@link EnsuresQualifier}. The value {@code qualifier} that is
* necessary for a postcondition specified with {@link EnsuresQualifier} is specified here with the
* value {@code qualifier}.
*
* The annotation E that is meta-annotated as {@link PostconditionAnnotation} must have an
* element called {@code value} that is an array of {@code String}s of the same format and with the
* same meaning as the value {@code expression} in {@link EnsuresQualifier}.
*
*
The established postcondition P has type specified by the {@code qualifier} field of this
* annotation. If the annotation E has elements annotated by {@link 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 {@link QualifierArgument} in E gives the name of the
* corresponding element in P.
*
*
For example, the following code declares a postcondition annotation for the {@link
* org.checkerframework.common.value.qual.MinLen} qualifier:
*
*
* {@literal @}PostconditionAnnotation(qualifier = MinLen.class)
* {@literal @}Target({ElementType.METHOD, ElementType.CONSTRUCTOR})
* public {@literal @}interface EnsuresMinLen {
* String[] value();
* {@literal @}QualifierArgument("value")
* int targetValue() default 0;
*
*
* The {@code value} element holds the expressions to which the qualifier applies and {@code
* targetValue} holds the value for the {@code value} argument of {@link
* org.checkerframework.common.value.qual.MinLen}.
*
* The following code then uses the annotation on a method that ensures {@code field} to be
* {@code @MinLen(2)} upon return.
*
*
* {@literal @}EnsuresMinLen(value = "field", targetValue = 2")
* public void setField(String argument) {
* field = "(" + argument + ")";
* }
*
*
* @see EnsuresQualifier
* @see QualifierArgument
*/
@Target({ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface PostconditionAnnotation {
/** The qualifier that will be established as a postcondition. */
Class qualifier();
}