/*

* Copyright 2015-2018 the original author or authors.

*

* 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.yoiojava.util;

import java.lang.reflect.ParameterizedType;

import java.lang.reflect.Type;

import com.yoiojava.logging.Log;

import com.yoiojava.logging.LogFactory;

/**

* @author hanjun

*/

public class Reflections {

private static Log logger = LogFactory.getLog(Reflections.class);

/**

* with Reflections,get Class generic parameters are defined in the

* statement, Note: the generic must be defined in the superclass if not

* found , otherwise return Object.class.

*

* eg. public User extends Model<User>

*

* @param clazz

* The class to introspect

* @return the first generic declaration, or Object.class if cannot be

* determined

*/

public static <T> Class<T> getClassGenricType(final Class clazz) {

return getClassGenricType(clazz, 0);

}

/**

* with Reflections,get Class generic parameters are defined in the

* statement, Note: the generic must be defined in the superclass if not

* found , otherwise return Object.class.

*

* eg. public User extends Model<User>

*

* @param clazz

* clazz The class to introspect

* @param index

* the Index of the generic ddeclaration,start from 0.

* @return the index generic declaration, or Object.class if cannot be

* determined

*/

public static Class getClassGenricType(final Class clazz, final int index) {

Type genType = clazz.getGenericSuperclass();

if (!(genType instanceof ParameterizedType)) {

// logger.warn(clazz.getSimpleName()

// + "'s superclass not ParameterizedType");

return Object.class;

}

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

if (index >= params.length || index < 0) {

logger.warn("Index: " + index + ", Size of "

+ clazz.getSimpleName() + "'s Parameterized Type: "

+ params.length);

return Object.class;

}

if (!(params[index] instanceof Class)) {

logger.warn(clazz.getSimpleName()

+ " not set the actual class on superclass generic parameter");

return Object.class;

}

return (Class) params[index];

}

}