package com.bcxin.signature.util.common;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.xml.ResourceEntityResolver;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class SpringContextUtil implements ApplicationContextAware {
	private static ConfigurableApplicationContext applicationContext; // Spring应用上下文环境

	/**
	 * 实现ApplicationContextAware接口的回调方法，设置上下文环境
	 * 
	 * @param applicationContext
	 * @throws BeansException
	 */
	public void setApplicationContext(ApplicationContext applicationContext)
			throws BeansException {
		SpringContextUtil.applicationContext = (ConfigurableApplicationContext) applicationContext;
	}

	/**
	 * @return ApplicationContext
	 */
	public static ConfigurableApplicationContext getApplicationContext() {
		return applicationContext;
	}

	/**
	 * 获取对象
	 * 
	 * @param name
	 * @return Object 一个以所给名字注册的bean的实例
	 * @throws BeansException
	 */
	public static Object getBean(String name) throws BeansException {
		return applicationContext.getBean(name);
	}

	/**
	 * 获取类型为requiredType的对象
	 * 如果bean不能被类型转换，相应的异常将会被抛出（BeanNotOfRequiredTypeException）
	 * 
	 * @param name
	 *            bean注册名
	 * @param requiredType
	 *            返回对象类型
	 * @return Object 返回requiredType类型对象
	 * @throws BeansException
	 */
	public static Object getBean(String name, Class requiredType)
			throws BeansException {
		return applicationContext.getBean(name, requiredType);
	}

	/**
	 * 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
	 * 
	 * @param name
	 * @return boolean
	 */
	public static boolean containsBean(String name) {
		return applicationContext.containsBean(name);
	}

	/**
	 * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。
	 * 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
	 * 
	 * @param name
	 * @return boolean
	 * @throws NoSuchBeanDefinitionException
	 */
	public static boolean isSingleton(String name)
			throws NoSuchBeanDefinitionException {
		return applicationContext.isSingleton(name);
	}

	/**
	 * @param name
	 * @return Class 注册对象的类型
	 * @throws NoSuchBeanDefinitionException
	 */
	public static Class getType(String name)
			throws NoSuchBeanDefinitionException {
		return applicationContext.getType(name);
	}

	/**
	 * 如果给定的bean名字在bean定义中有别名，则返回这些别名
	 * 
	 * @param name
	 * @return
	 * @throws NoSuchBeanDefinitionException
	 */
	public static String[] getAliases(String name)
			throws NoSuchBeanDefinitionException {
		return applicationContext.getAliases(name);
	}
	
	/**
	 * 向spring的beanFactory动态地装载bean
	 * 
	 * @param configLocationString
	 *            要装载的bean所在的xml配置文件位置。 spring配置中的contextConfigLocation，同样支持诸如
	 *            "/WEB-INF/ApplicationContext-*.xml"的写法。
	 */
	public void loadBean(String configLocationString) {
		XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(
				(BeanDefinitionRegistry) getApplicationContext().getBeanFactory());
		beanDefinitionReader.setResourceLoader(getApplicationContext());
		beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(getApplicationContext()));
		try {
			String[] configLocations = new String[] { configLocationString };
			for (int i = 0; i < configLocations.length; i++) {
				beanDefinitionReader.loadBeanDefinitions(getApplicationContext().getResources(configLocations[i]));
			}
		} catch (BeansException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}