Java Reflection Generic Type getGenericType(Type genType, int index)

Description

get Generic Type

License

Apache License

Declaration

public static Class getGenericType(Type genType, int index) 

Method Source Code

//package com.java2s;
/*/*from w w w. j  a v a  2 s .c o  m*/
 * Copyright (c) 2015-2020, Chen Rui
 *
 * 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.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

public class Main {

    public static Class getGenericType(Type genType, int index) {
        if (!(genType instanceof ParameterizedType)) {
            while (!Object.class.equals(genType) && !(genType instanceof ParameterizedType)) {
                genType = ((Class) genType).getGenericSuperclass();
            }

            if (Object.class.equals(genType)) {
                return Object.class;
            }
        }

        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

        if (index >= params.length || index < 0) {
            //log.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: " + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            //log.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
            return Object.class;
        }
        return (Class) params[index];
    }
}

Related

1. getGenericSuperType(Type t)
2. getGenericType(@Nullable Type genericType)
3. getGenericType(Member member, int index)
4. getGenericType(Method setter)
5. getGenericType(Object target)
6. getGenericType(Type t, int index)
7. getGenericType(Type type)
8. getGenericTypeArguments(Method m, int i)
9. getGenericTypeName(Method method)