get Inherited Annotations - Java java.lang.annotation

Java examples for java.lang.annotation:Annotation Attribute

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Description

get Inherited Annotations

Demo Code


//package com.java2s;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Set;

public class Main {
    public static void main(String[] argv) throws Exception {
        Class type = String.class;
        Class annotation = String.class;
        System.out.println(getInheritedAnnotations(type, annotation));
    }/*from   w w  w .ja va2 s. c  om*/

    public static <A extends Annotation> Set<A> getInheritedAnnotations(
            Class<?> type, Class<A> annotation) {
        Set<A> annotations = new HashSet<>();

        getInheritedAnnotations(type, annotation, annotations);

        return annotations;
    }

    public static <A extends Annotation> void getInheritedAnnotations(
            Class<?> type, Class<A> annotation, Set<A> annotations) {
        A annotaionValue = type.getAnnotation(annotation);
        if (annotaionValue != null) {
            annotations.add(annotaionValue);
        }

        if (type.getSuperclass() != Object.class
                && type.getSuperclass() != null) {
            getInheritedAnnotations(type.getSuperclass(), annotation,
                    annotations);
        }

        if (type.getInterfaces() != null) {
            for (Class<?> clazz : type.getInterfaces()) {
                getInheritedAnnotations(clazz, annotation, annotations);
            }
        }
    }

    public static <A extends Annotation> Set<A> getInheritedAnnotations(
            Method method, Class<A> annotation) {
        Set<A> annotations = new HashSet<>();

        getInheritedAnnotations(method, annotation, annotations);

        return annotations;
    }

    public static <A extends Annotation> void getInheritedAnnotations(
            Method method, Class<A> annotation, Set<A> annotations) {
        A annotationValue = method.getAnnotation(annotation);
        if (annotationValue != null) {
            annotations.add(annotationValue);
        }

        try {
            Class<?> declaringClass = method.getDeclaringClass();
            if (declaringClass.getSuperclass() != Object.class
                    && declaringClass.getSuperclass() != null) {
                getInheritedAnnotations(declaringClass.getSuperclass(),
                        annotation, annotations);
            }

            if (declaringClass.getInterfaces() != null) {
                for (Class<?> clazz : declaringClass.getInterfaces()) {
                    Method superMethod = clazz.getMethod(method.getName(),
                            method.getParameterTypes());
                    if (superMethod != null) {
                        getInheritedAnnotations(superMethod, annotation,
                                annotations);
                    }
                }
            }
        } catch (NoSuchMethodException e) {
        }
    }
}

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