find Annotation from a class by Annotation Type - Java java.lang.annotation

Java examples for java.lang.annotation:Class Annotation

  1. HOME
  2. Java
  3. java.lang.annotation
  4. Class Annotation

Description

find Annotation from a class by Annotation Type

Demo Code

/*/*from   ww w.  j  a  v a2  s .c o m*/
 * Copyright 2011 Alibaba Group Holding Limited.
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
//package com.java2s;
import java.lang.annotation.Annotation;

public class Main {
    public static void main(String[] argv) throws Exception {
        Class clazz = String.class;
        Class annotationType = String.class;
        System.out.println(findAnnotation(clazz, annotationType));
    }

    public static <A extends Annotation> A findAnnotation(Class<?> clazz,
            Class<A> annotationType) {
        A annotation = clazz.getAnnotation(annotationType);
        if (annotation != null) {
            return annotation;
        }
        for (Class<?> ifc : clazz.getInterfaces()) {
            annotation = findAnnotation(ifc, annotationType);
            if (annotation != null) {
                return annotation;
            }
        }
        Class<?> superClass = clazz.getSuperclass();
        if (superClass == null || superClass == Object.class) {
            return null;
        }
        return findAnnotation(superClass, annotationType);
    }
}

Related Tutorials