find Parameter Annotation - Java java.lang.annotation

Java examples for java.lang.annotation:Annotation Parameter

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

Description

find Parameter Annotation

Demo Code

/**/*from  w  w  w .  ja va 2  s .c o  m*/
 *
 *     Copyright (C) norad.fr
 *
 *     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;

import java.lang.reflect.Method;

public class Main {
    public static <A extends Annotation> A findParameterAnnotation(
            Method method, int position, Class<A> annotationType) {
        if (position < 0
                || position > method.getParameterAnnotations().length - 1) {
            throw new IllegalStateException("Param position " + position
                    + " overflow for method : " + method);
        }

        A annotation = getParameterAnnotation(method, annotationType,
                position);
        Class<?> cl = method.getDeclaringClass();
        if (annotation == null) {
            annotation = searchParamAnnotationOnInterfaces(method,
                    annotationType, cl.getInterfaces(), position);
        }
        while (annotation == null) {
            cl = cl.getSuperclass();
            if (cl == null || cl == Object.class) {
                break;
            }
            try {
                Method equivalentMethod = cl.getDeclaredMethod(
                        method.getName(), method.getParameterTypes());
                annotation = getParameterAnnotation(equivalentMethod,
                        annotationType, position);
                if (annotation == null) {
                    annotation = searchParamAnnotationOnInterfaces(method,
                            annotationType, cl.getInterfaces(), position);
                }
            } catch (NoSuchMethodException ex) {
                // We're done...
            }
        }
        return annotation;
    }

    public static <T extends Annotation> T getParameterAnnotation(
            Method method, Class<T> annotationType, int position) {
        for (Annotation annotation : method.getParameterAnnotations()[position]) {
            if (annotation.annotationType()
                    .isAssignableFrom(annotationType)) {
                return (T) annotation;
            }
        }
        return null;
    }

    private static <A extends Annotation> A searchParamAnnotationOnInterfaces(
            Method method, Class<A> annotationType, Class<?>[] ifcs,
            int position) {
        for (Class<?> iface : ifcs) {
            try {
                Method method2 = iface.getMethod(method.getName(),
                        method.getParameterTypes());
                A parameterAnnotation = getParameterAnnotation(method2,
                        annotationType, position);
                if (parameterAnnotation != null) {
                    return parameterAnnotation;
                }
            } catch (SecurityException | NoSuchMethodException e) {
                // nothing to do
            }
        }
        return null;
    }
}

Related Tutorials