car=com.fastcampus.ch3.diCopy2.Truck
engine=com.fastcampus.ch3.diCopy2.Engine

package com.fastcampus.ch3.diCopy1;

import java.io.FileReader;
import java.util.Properties;

class Car {}
class SportsCar extends Car{}
class Truck extends Car {}
class Engine {}

public class Main1 {
    public static void main(String[] args) throws Exception {
        Car car = (Car)getObject("car");
        Engine engine = (Engine) getObject("engine");
        System.out.println("car = " + car);
        System.out.println("engine = " + engine);
    }
    static Object getObject(String key) throws Exception {
        Properties p = new Properties();
        p.load(new FileReader("config.txt"));

        Class clazz = Class.forName(p.getProperty(key));

        return clazz.newInstance();
    }

    static Car getCar() throws Exception {
        Properties p = new Properties();
        p.load(new FileReader("config.txt"));

        Class clazz = Class.forName(p.getProperty("car"));

        return (Car)clazz.newInstance();
    }
}

package com.fastcampus.ch3.aop;

import org.springframework.transaction.annotation.Transactional;

import java.lang.reflect.Method;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class AopMain {
    public static void main(String[] args) throws Exception {
        MyAdvice myAdvice = new MyAdvice();

        Class myClass = Class.forName("com.fastcampus.ch3.aop.MyClass");
        Object obj = myClass.newInstance();

        for(Method m : myClass.getDeclaredMethods()) {
            myAdvice.invoke(m, obj, null);
        }
    }
}

class MyAdvice {
    Pattern p = Pattern.compile("a.*");

    boolean matches(Method m){
        Matcher matcher = p.matcher(m.getName());
        return matcher.matches();
    }

    void invoke(Method m, Object obj, Object... args) throws Exception {
        if(m.getAnnotation(Transactional.class)!=null)
            System.out.println("[before]{");

        m.invoke(obj, args); // aaa(), aaa2(), bbb() 호출가능

        if(m.getAnnotation(Transactional.class)!=null)
            System.out.println("}[after]");
    }
}

class MyClass {
    @Transactional
    void aaa() {
        System.out.println("aaa() is called.");
    }
    void aaa2() {
        System.out.println("aaa2() is called.");
    }
    void bbb() {
        System.out.println("bbb() is called.");
    }
}