Java Reflection Annotation getAnnotation(Class theExaminedClass, Class theExpectedAnnotation)

Description

The method returns the expected annotation.

License

Open Source License

Parameter

Parameter	Description
theExaminedClass	the class which is to be examined
theExpectedAnnotation	the expected annotation type

Return

the specified annotation or null if no such annotation exists

Declaration

public static Annotation getAnnotation(Class theExaminedClass, Class theExpectedAnnotation) 

Method Source Code

//package com.java2s;
/*/*from  w ww .ja  v  a2  s. c  om*/
 * (J)ava (M)iscellaneous (U)tilities (L)ibrary
 *
 * JMUL is a central repository for utilities which are used in my
 * other public and private repositories.
 *
 * Copyright (C) 2013  Kristian Kutin
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * e-mail: kristian.kutin@arcor.de
 */

import java.lang.annotation.Annotation;

public class Main {
    /**
     * The method returns the expected annotation.
     *
     * @param theExaminedClass
     *        the class which is to be examined
     * @param theExpectedAnnotation
     *        the expected annotation type
     *
     * @return the specified annotation or <code>null</code> if no such
     *         annotation exists
     */
    public static Annotation getAnnotation(Class theExaminedClass, Class theExpectedAnnotation) {

        return getAnnotation(theExaminedClass, theExpectedAnnotation, false);
    }

    /**
     * The method returns the expected annotation. Optionally the parent classes
     * can be examined as well.
     *
     * @param theExaminedClass
     *        the class which is to be examined
     * @param theExpectedAnnotation
     *        the expected annotation type
     * @param recurse
     *        the flag indicates if the parent classes should be examined
     *
     * @return the specified annotation or <code>null</code> if no such
     *         annotation exists
     */
    public static Annotation getAnnotation(Class theExaminedClass, Class theExpectedAnnotation, boolean recurse) {

        Class probedType = theExaminedClass;

        while (recurse && (probedType != null)) {

            if (probedType.isAnnotationPresent(theExpectedAnnotation)) {

                return probedType.getAnnotation(theExpectedAnnotation);

            } else {

                probedType = probedType.getSuperclass();
            }
        }

        return null;
    }

    /**
     * The method checks if a class possesses a specific annotation. Optionally
     * the parent classes can be examined as well.
     *
     * @param theExaminedClass
     *        the class which is to be examined
     * @param theExpectedAnnotation
     *        the expected annotation type
     *
     * @return <code>true</code> if the annotation exists, else
     *         <code>false</code>
     */
    public static boolean isAnnotationPresent(Class theExaminedClass, Class theExpectedAnnotation) {

        return isAnnotationPresent(theExaminedClass, theExpectedAnnotation, false);
    }

    /**
     * The method checks if a class possesses a specific annotation. Optionally
     * the parent classes can be examined as well.
     *
     * @param theExaminedClass
     *        the class which is to be examined
     * @param theExpectedAnnotation
     *        the expected annotation type
     * @param recurse
     *        the flag indicates if the parent classes should be examined
     *
     * @return <code>true</code> if the annotation exists, else
     *         <code>false</code>
     */
    public static boolean isAnnotationPresent(Class theExaminedClass, Class theExpectedAnnotation,
            boolean recurse) {

        Class probedType = theExaminedClass;
        boolean result = false;

        while (recurse && (probedType != null)) {

            result = probedType.isAnnotationPresent(theExpectedAnnotation);

            if (result) {

                break;

            } else {

                probedType = probedType.getSuperclass();
            }
        }

        return result;
    }
}

Related

1. getAnnotation(Annotation[] annotations, Class annotationType)
2. getAnnotation(Annotation[] annotations, Class clazz)
3. getAnnotation(Class clazz, Class annotation)
4. getAnnotation(Class cls, Class annotationCls)
5. getAnnotation(Class cls, Class annotationCls)
6. getAnnotation(Class anno, Class cl)
7. getAnnotation(Class annotationClass, Annotation[] annotations)
8. getAnnotation(Class base, Class annotationClass)
9. getAnnotation(Class c, Class annotationClass)