ReflectionHelper.java Source code

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Here is the source code for ReflectionHelper.java

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// $Id: ReflectionHelper.java 16271 2009-04-07 20:20:12Z hardy.ferentschik $
/*
* JBoss, Home of Professional Open Source
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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.
*/

import java.beans.Introspector;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * Some reflection utility methods.
 *
 * @author Hardy Ferentschik
 */
public class ReflectionHelper {

    /**
     * @param type the type to check.
     *
     * @return Returns <code>true</code> if <code>type</code> is a iterable type, <code>false</code> otherwise.
     */
    public static boolean isIterable(Type type) {
        if (type instanceof Class && isIterableClass((Class) type)) {
            return true;
        }
        if (type instanceof ParameterizedType) {
            return isIterable(((ParameterizedType) type).getRawType());
        }
        if (type instanceof WildcardType) {
            Type[] upperBounds = ((WildcardType) type).getUpperBounds();
            return upperBounds.length != 0 && isIterable(upperBounds[0]);
        }
        return false;
    }

    /**
     * Checks whether the specified class parameter is an instance of a collection class.
     *
     * @param clazz <code>Class</code> to check.
     *
     * @return <code>true</code> is <code>clazz</code> is instance of a collection class, <code>false</code> otherwise.
     */
    private static boolean isIterableClass(Class<?> clazz) {
        List<Class<?>> classes = new ArrayList<Class<?>>();
        computeClassHierarchy(clazz, classes);
        return classes.contains(Iterable.class);
    }

    /**
     * Get all superclasses and interfaces recursively.
     *
     * @param clazz The class to start the search with.
     * @param classes List of classes to which to add all found super classes and interfaces.
     */
    private static void computeClassHierarchy(Class<?> clazz, List<Class<?>> classes) {
        for (Class current = clazz; current != null; current = current.getSuperclass()) {
            if (classes.contains(current)) {
                return;
            }
            classes.add(current);
            for (Class currentInterface : current.getInterfaces()) {
                computeClassHierarchy(currentInterface, classes);
            }
        }
    }
}