CODEWITHSUNDEEP
javaclassannotationsannotation-processingannotations-processing-messager
Gangnus
Gangnus

Reputation: 24464

Can I find the appropriate MirrorAnnotation in a short way?

If I want IDE to show an error from annotation processing on the annotation itself, I should use the following form of printMessage():

printMessage​(Diagnostic.Kind kind, CharSequence msg, Element e, AnnotationMirror a)

But I cannot find a nice and simple way to get that AnnotationMirror.

Using code samples, these and these, combining what I found there, I had found a complicated way:

@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
    Set<? extends Element> classesForBuilder = roundEnv.getElementsAnnotatedWith(AddBuilder.class);
    for(Element classElement : classesForBuilder){
        if (classElement.getModifiers().contains(Modifier.ABSTRACT)) {
            return annoError(classElement, "AnnoBuilder cannot be applied to an abstract class.", AddBuilder.class);
.......

boolean annoError(Element annotatedElement, String message, Class<? extends Annotation> annoClass ){
    for(AnnotationMirror annotationMirror : annotatedElement.getAnnotationMirrors()){
>>>>>>>>if(((TypeElement)annotationMirror.getAnnotationType().asElement())
           .getQualifiedName().toString()
           .equals( annoClass.getCanonicalName())) {
            messager.printMessage(Kind.ERROR, message, annotatedElement, annotationMirror);
        } else {
            messager.printMessage(Kind.ERROR, message+" + no Annotation found.", annotatedElement);
        }
    }
    return true;
}

That works. But I do not like the really terrible second if.

I had found a shorter way of comparison through String:

if(annotationMirror.getAnnotationType().toString().equals(annoClass.getCanonicalName()))

I do not understand why only that super-long way of comparison through many classes is used in all published examples.

But still I would like to have it shorter. 

if(annotationMirror.getAnnotationType().equals(annoClass))

does not work.

Can I compare classes somehow without turning them into names?

Upvotes: 1

Views: 150

Answers (1)

Ahmad Bawaneh
Ahmad Bawaneh

Reputation: 1054

I think what you are asking for present in the Types class and you can use the isSameType method like this

annotatedElement.getAnnotationMirrors()
                .stream()
                .filter(annotationMirror -> types.isSameType(annotationMirror.getAnnotationType(), elements.getTypeElement(annoClass.getCanonicalName()).asType()))
                .findFirst()
                .map(annotationMirror -> {
                    messager.printMessage(Diagnostic.Kind.ERROR, message, annotatedElement, annotationMirror);
                    return true;
                })
                .orElseGet(() -> {
                    messager.printMessage(Diagnostic.Kind.ERROR, message + " + no Annotation found.", annotatedElement);
                    return false;
                });

And you should not use Strings literals obtained from types names for comparison like this as it might work differently between intellij and eclipse.

Upvotes: 1

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