Add fields declared in the given Class object that are annotated with the specified annotation type to the given list. - Java java.lang.annotation

Java examples for java.lang.annotation:Field Annotation

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Description

Add fields declared in the given Class object that are annotated with the specified annotation type to the given list.

Demo Code

/*******************************************************************************
 * Copyright 2012 Geoscience Australia//from ww w  .j av  a 2 s.co m
 * 
 * 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.Field;
import java.lang.reflect.Method;

import java.util.List;

public class Main {


    /**
     * Add fields declared in the given Class object that are annotated with the
     * specified annotation type to the given list. Also searches super-classes.
     * 
     * @param type
     * @param annotationClass
     * @param fieldList
     */
    protected static <T extends Annotation> void addAnnotatedFieldsToList(
            Class<?> type, Class<T> annotationClass, List<Field> fieldList) {
        if (type == null) {
            return;
        }
        Field[] fields = type.getDeclaredFields();
        for (Field field : fields) {
            if (getAnnotation(field, annotationClass) != null) {
                fieldList.add(field);
            }
        }
        addAnnotatedFieldsToList(type.getSuperclass(), annotationClass,
                fieldList);
    }

    /**
     * Return the provided Class' annotation for the specified type if such an
     * annotation is present, else null. Searches super-interfaces, and returns
     * the first annotation found.
     * 
     * @param type
     *            Class to test
     * @param annotationClass
     *            The Class object corresponding to the annotation type
     * @return The annotation for the specified annotation type if present on
     *         the given Class, or any of its implemented interfaces, else null
     * @see Class#getAnnotation(Class)
     */
    public static <T extends Annotation> T getAnnotation(Class<?> type,
            Class<T> annotationClass) {
        T t = type.getAnnotation(annotationClass);
        if (t != null) {
            return t;
        }
        for (Class<?> i : type.getInterfaces()) {
            if ((t = getAnnotation(i, annotationClass)) != null) {
                return t;
            }
        }
        return null;
    }

    /**
     * Return the provided Method's annotation for the specified type if such an
     * annotation is present, else null. Also searches super-classes and
     * super-interfaces for a matching method signature with the annotation, and
     * returns the first annotation found.
     * 
     * @param method
     *            Method to test
     * @param annotationClass
     *            The Class object corresponding to the annotation type
     * @return The annotation for the specified annotation type if present on
     *         the given Method, or any super-methods, else null.
     * @see Method#getAnnotation(Class)
     */
    public static <T extends Annotation> T getAnnotation(Method method,
            Class<T> annotationClass) {
        T t = method.getAnnotation(annotationClass);
        if (t != null) {
            return t;
        }

        Class<?> type = method.getDeclaringClass();
        for (Class<?> i : type.getInterfaces()) {
            try {
                Method m = i.getDeclaredMethod(method.getName(),
                        method.getParameterTypes());
                if (m.getReturnType().equals(method.getReturnType())
                        && (t = getAnnotation(m, annotationClass)) != null) {
                    return t;
                }
            } catch (NoSuchMethodException e) {
            }
        }
        return null;
    }

    /**
     * Return the provided Field's annotation for the specified type if such an
     * annotation is present, else null.
     * 
     * @param field
     *            Field to test
     * @param annotationClass
     *            The Class object corresponding to the annotation type
     * @return The annotation for the specified annotation type if present on
     *         the given Field, else null.
     * @see Field#getAnnotation(Class)
     */
    public static <T extends Annotation> T getAnnotation(Field field,
            Class<T> annotationClass) {
        return field.getAnnotation(annotationClass);
    }
}

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