package com.IocExample;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.util.Map;

import java.util.concurrent.ConcurrentHashMap;

/***

 * @description: IoC容器例子

 * @author:

 * @create: 2019-08-09 15:40

 *

 * 1、实例化bean

 * 2、保存bean

 * 3、提供bean

 * 4、每一个ben要产生一个唯一的id与之相呼应

 **/

public class IoCContainer {

    private Map<String, Object>  beans = new ConcurrentHashMap<String, Object>();

    /**

     * 根据beanId获取一个bean

     * @param beanId

     * @return 返回Bean

     */

    public Object getBean(String beanId){

        return beans.get(beanId);

    }

    /**

     * 委托IoC容器创建一个Bean

     * @param clazz 要创建的bean的class

     * @param beanId beanId

     * @param paramBeanId 要创建的bean的class的构造方法所需要的参数的beanId们（依赖的beanId）

     */

    public void setBean(Class<?> clazz, String beanId,String... paramBeanId){

        //1\组装构造方法所需要的参数值--获取依赖bean

        Object[] paramValues = new Object[paramBeanId.length] ;

        for (int i = 0; i < paramBeanId.length; i++){

            paramValues[i] = beans.get(paramBeanId[i]);

            System.out.println("paramValues["+ i + "] =" + paramValues[i]);

        }

        //2、调用构造方法实例化bean

        Object bean = null;

        //获取所有构造函数

        for (Constructor<?> constructor : clazz.getConstructors()) {

            try{

                bean = constructor.newInstance(paramValues);

            } catch (IllegalAccessException e) {

            } catch (InstantiationException e) {

            } catch (InvocationTargetException e) {

            }

            if (bean == null){

                throw new RuntimeException("找不到合适的构造方法");

            }

        }

        //3、将实例化的bean放入beans

        beans.put(beanId, bean);

    }

}