package com.dy.common.springUtil;

import org.springframework.beans.BeansException;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

import java.util.Map;

/**
 * 获取Springboot上下文，并通过上下文可以获取配置文件中的配置参数。
 * SpringBoot启动时，发现本类注解了@Component，会加载本类并实例化，
 * 实例化时发现本类实现了接口ApplicationContextAware，则会调用
 * setApplicationContext方法设置Spring上下文对象
 */
@Component
public class SpringContextUtil implements ApplicationContextAware {

    private static ApplicationContext applicationContext = null;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (SpringContextUtil.applicationContext == null) {
            SpringContextUtil.applicationContext = applicationContext;
        }
    }

    //获取applicationContext
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    //通过name获取 Bean.
    public static Object getBean(String name) {
        return getApplicationContext().getBean(name);
    }

    //通过class获取Bean.
    public static <T> T getBean(Class<T> clazz) {
        return getApplicationContext().getBean(clazz);
    }

    /**
     * 同步方法注册bean到ApplicationContext中
     *
     * @param beanName
     * @param clazz
     * @param original bean的属性值
     */
    public static synchronized void setBean(String beanName, Class<?> clazz, Map<String,Object> original) {
        //checkApplicationContext();
        DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
        if(beanFactory.containsBean(beanName)){
            return;
        }
        //BeanDefinition beanDefinition = new RootBeanDefinition(clazz);
        GenericBeanDefinition definition = new GenericBeanDefinition();
        //类class
        definition.setBeanClass(clazz);
        //属性赋值
        definition.setPropertyValues(new MutablePropertyValues(original));
        //注册到spring上下文
        beanFactory.registerBeanDefinition(beanName, definition);
    }

}