package org.amigo.proxy;
import java.io.InputStream;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
/**
* bean工廠類.
* @author <a href="mailto:xiexingxing1121@126.com">AmigoXie</a>
* Creation date: 2007-10-7 - 下午04:04:34
*/
public class BeanFactory {
private Map<String, Object> beanMap = new HashMap<String, Object>();
/**
* bean工廠的初始化.
* @param xml xml配置文件
*/
    public void init(String xml) {
try {
//讀取指定的配置文件
            SAXReader reader = new SAXReader();
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream ins = classLoader.getResourceAsStream(xml);
Document doc = reader.read(ins);
Element root = doc.getRootElement();
Element foo;
//創(chuàng)建AOP處理器
            AopHandler aopHandler = new AopHandler();
//遍歷bean
            for (Iterator i = root.elementIterator("bean"); i.hasNext();) {
foo = (Element) i.next();
//獲取bean的屬性id、class、aop以及aopType
                Attribute id = foo.attribute("id");
Attribute cls = foo.attribute("class");
Attribute aop = foo.attribute("aop");
Attribute aopType = foo.attribute("aopType");
//配置了aop和aopType屬性時(shí)，需進(jìn)行攔截操作
                if (aop != null && aopType != null) {
//根據(jù)aop字符串獲取對(duì)應(yīng)的類
                    Class advisorCls = Class.forName(aop.getText());
//創(chuàng)建該類的對(duì)象
                    Advisor advisor = (Advisor) advisorCls.newInstance();
//根據(jù)aopType的類型來設(shè)置前置或后置顧問
                    if ("before".equals(aopType.getText())) {
aopHandler.setBeforeAdvisor(advisor);
} else if ("after".equals(aopType.getText())) {
aopHandler.setAfterAdvisor(advisor);
}
}
//利用Java反射機(jī)制，通過class的名稱獲取Class對(duì)象
                Class bean = Class.forName(cls.getText());
//獲取對(duì)應(yīng)class的信息
                java.beans.BeanInfo info = java.beans.Introspector.getBeanInfo(bean);
//獲取其屬性描述
                java.beans.PropertyDescriptor pd[] = info.getPropertyDescriptors();
//設(shè)置值的方法
                Method mSet = null;
//創(chuàng)建一個(gè)對(duì)象
                Object obj = bean.newInstance();
//遍歷該bean的property屬性
                for (Iterator ite = foo.elementIterator("property"); ite.hasNext();) {
Element foo2 = (Element) ite.next();
//獲取該property的name屬性
                    Attribute name = foo2.attribute("name");
String value = null;
//獲取該property的子元素value的值
                    for(Iterator ite1 = foo2.elementIterator("value"); ite1.hasNext();) {
Element node = (Element) ite1.next();
value = node.getText();
break;
}
for (int k = 0; k < pd.length; k++) {
if (pd[k].getName().equalsIgnoreCase(name.getText())) {
mSet = pd[k].getWriteMethod();
//利用Java的反射極致調(diào)用對(duì)象的某個(gè)set方法，并將值設(shè)置進(jìn)去
                            mSet.invoke(obj, value);
}
}
}
//為對(duì)象增加前置或后置顧問
                obj = (Object) aopHandler.setObject(obj);
//將對(duì)象放入beanMap中，其中key為id值，value為對(duì)象
                beanMap.put(id.getText(), obj);
}
} catch (Exception e) {
System.out.println(e.toString());
}
}
/**
* 通過bean的id獲取bean的對(duì)象.
* @param beanName bean的id
* @return 返回對(duì)應(yīng)對(duì)象
*/
    public Object getBean(String beanName) {
Object obj = beanMap.get(beanName);
return obj;
}
/**
* 測試方法.
* @param args
*/
    public static void main(String[] args) {
BeanFactory factory = new BeanFactory();
factory.init("config.xml");
BusinessObj obj = (BusinessObj) factory.getBean("businessObj");
obj.process();
}
}