java замена значений в annotation runtime

java-Замена значений в annotation runtime

https://rationaleemotions.wordpress.com/2016/05/27/changing-annotation-values-at-runtime/

[code:]java[:code]
public class AnnotationHelper {
    private static final String ANNOTATIONS = "annotations";
    public static final String ANNOTATION_DATA = "annotationData";
 
    public static boolean isJDK7OrLower() {
        boolean jdk7OrLower = true;
        try {
            Class.class.getDeclaredField(ANNOTATIONS);
        } catch (NoSuchFieldException e) {
            //Willfully ignore all exceptions
            jdk7OrLower = false;
        }
        return jdk7OrLower;
    }
 
    public static void alterAnnotationOn(Class clazzToLookFor, Class<? extends Annotation> annotationToAlter,Annotation annotationValue) {
        if (isJDK7OrLower()) {
            try {
                Field annotations = Class.class.getDeclaredField(ANNOTATIONS);
                annotations.setAccessible(true);
                Map<Class<? extends Annotation>, Annotation> map =
                    (Map<Class<? extends Annotation>, Annotation>) annotations.get(clazzToLookFor);
                map.put(annotationToAlter, annotationValue);
            } catch (Exception  e) {
                e.printStackTrace();
            }
        } else {
            try {
                //In JDK8 Class has a private method called annotationData().
                //We first need to invoke it to obtain a reference to AnnotationData class which is a private class
                Method method = Class.class.getDeclaredMethod(ANNOTATION_DATA, null);
                method.setAccessible(true);
                //Since AnnotationData is a private class we cannot create a direct reference to it. We will have to
                //manage with just Object
                Object annotationData = method.invoke(clazzToLookFor);
                //We now look for the map called "annotations" within AnnotationData object.
                Field annotations = annotationData.getClass().getDeclaredField(ANNOTATIONS);
                annotations.setAccessible(true);
                Map<Class<? extends Annotation>, Annotation> map =
                    (Map<Class<? extends Annotation>, Annotation>) annotations.get(annotationData);
                map.put(annotationToAlter, annotationValue);
            } catch (Exception  e) {
                e.printStackTrace();
            }
        }
    }
}
[/code]