Java Reflection Generic Type from Class getGenericClass(Class cls)

Description

get Generic Class

License

Apache License

Declaration

public static Class<?> getGenericClass(Class<?> cls) 

Method Source Code

//package com.java2s;
/*//from  w  w  w  . j av  a2  s  .c o  m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.lang.reflect.GenericArrayType;

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

public class Main {
    public static Class<?> getGenericClass(Class<?> cls) {
        return getGenericClass(cls, 0);
    }

    public static Class<?> getGenericClass(Class<?> cls, int i) {
        try {
            ParameterizedType parameterizedType = ((ParameterizedType) cls.getGenericInterfaces()[0]);
            Object genericClass = parameterizedType.getActualTypeArguments()[i];
            if (genericClass instanceof ParameterizedType) {
                return (Class<?>) ((ParameterizedType) genericClass).getRawType();
            } else if (genericClass instanceof GenericArrayType) {
                Type type = ((GenericArrayType) genericClass).getGenericComponentType();
                if (type instanceof TypeVariable) {
                    return type.getClass();
                }
                return (((GenericArrayType) genericClass).getGenericComponentType() instanceof Class<?>)
                        ? (Class<?>) ((GenericArrayType) genericClass).getGenericComponentType()
                        : ((GenericArrayType) genericClass).getGenericComponentType().getClass();
            } else if (genericClass != null) {
                if (genericClass instanceof TypeVariable) {
                    return genericClass.getClass();
                }
                return (Class<?>) genericClass;
            }
        } catch (Throwable e) {

        }
        if (cls.getSuperclass() != null) {
            return getGenericClass(cls.getSuperclass(), i);
        } else {
            throw new IllegalArgumentException(cls.getName() + " generic type undefined!");
        }
    }
}

Related

1. getGenericClass(Class clazz)
2. getGenericClass(Class clazz, int index)
3. getGenericClass(Class clazz, int index)
4. getGenericClass(Class clazz)
5. getGenericClass(Class clazz, int index)
6. getGenericClass(final Class class1)
7. getGenericClass(final Class parametrizedClass, int pos)
8. getGenericClass(final Class parametrizedClass, int pos)
9. getGenericClass(final Method method)