Java Reflection Generic Type from Class getGenericClassType(Class clazz, Class filterClass)

Description

Extract the real Type from the passed class.

License

Open Source License

Parameter

Parameter	Description
clazz	the class to extract from
filterClass	the class of the generic type we're looking for

Return

the real Type from the interfaces of the passed class, filtered by the passed filter class

Declaration

public static Type getGenericClassType(Class clazz, Class filterClass) 

Method Source Code

//package com.java2s;
/*//from  w ww. j  ava 2s .  co m
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

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

public class Main {
    /**
     * Extract the real Type from the passed class. For example
     * <tt>public Class MyClass implements FilterClass&lt;A, B&gt;, SomeOtherClass&lt;C&gt;</tt> will return
     * <tt>FilterClass&lt;A, B&gt;, SomeOtherClass&lt;C&gt;</tt>.
     *
     * @param clazz the class to extract from
     * @param filterClass the class of the generic type we're looking for
     * @return the real Type from the interfaces of the passed class, filtered by the passed filter class
     * @since 4.0M1
     */
    public static Type getGenericClassType(Class clazz, Class filterClass) {
        for (Type type : clazz.getGenericInterfaces()) {
            if (type == filterClass) {
                return type;
            } else if (type instanceof ParameterizedType) {
                ParameterizedType pType = (ParameterizedType) type;
                if (filterClass.isAssignableFrom((Class) pType.getRawType())) {
                    return type;
                }
            }
        }

        return null;
    }
}

Related

1. getGenericClass(Object o)
2. getGenericClass(Object object, int index)
3. getGenericClass(Object source, ParameterizedType type)
4. getGenericClass(Type type)
5. getGenericClassByIndex(Type genericType, int index)
6. getGenericDeclaringType(Class baseClass, Class declaringClass)
7. getGenericFirstClass(Type type)
8. getGenericInterface(final Class sourceClass, final Class genericInterface)
9. getGenericInterfaceParamType(Class cls, Class rawType)