Java Reflection Annotation Find findAnnotationClass( Class<?> c, Class<?> base)

Description

This method will find the @{code T} in public class Foo extends BaseType .

License

Open Source License

Declaration

public static Class<? extends Annotation> findAnnotationClass(
        Class<?> c, Class<?> base)

Method Source Code

//package com.java2s;
/*/*w w  w  .  jav  a2  s  .  co  m*/
 * Copyright (C) 2009-2011 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

import java.lang.annotation.Annotation;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

public class Main {
    /**
     * This method will find the @{code T} in {@code public class Foo extends BaseType<T>}.
     * 
     * It returns an annotation type because it is used exclusively to figure out which annotations are
     * being handled by {@link lombok.eclipse.EclipseAnnotationHandler} and {@link lombok.javac.JavacAnnotationHandler}.
     */
    public static Class<? extends Annotation> findAnnotationClass(
            Class<?> c, Class<?> base) {
        if (c == Object.class || c == null)
            return null;
        Class<? extends Annotation> answer = null;

        answer = findAnnotationHelper(base, c.getGenericSuperclass());
        if (answer != null)
            return answer;

        for (Type iface : c.getGenericInterfaces()) {
            answer = findAnnotationHelper(base, iface);
            if (answer != null)
                return answer;
        }

        Class<? extends Annotation> potential = findAnnotationClass(
                c.getSuperclass(), base);
        if (potential != null)
            return potential;
        for (Class<?> iface : c.getInterfaces()) {
            potential = findAnnotationClass(iface, base);
            if (potential != null)
                return potential;
        }

        return null;
    }

    @SuppressWarnings("unchecked")
    private static Class<? extends Annotation> findAnnotationHelper(
            Class<?> base, Type iface) {
        if (iface instanceof ParameterizedType) {
            ParameterizedType p = (ParameterizedType) iface;
            if (!base.equals(p.getRawType()))
                return null;
            Type target = p.getActualTypeArguments()[0];
            if (target instanceof Class<?>) {
                if (Annotation.class.isAssignableFrom((Class<?>) target)) {
                    return (Class<? extends Annotation>) target;
                }
            }

            throw new ClassCastException("Not an annotation type: "
                    + target);
        }
        return null;
    }
}

Java Reflection Annotation Find findAnnotationClass( Class c, Class base)

Description

License

Declaration

Method Source Code

Related