package typeinfo;
class Base {
  static { System.out.println("加載Base類"); }
}
class Derived extends Base { 
  static { System.out.println("加載Derived類");}
}
public class Test {
  static void printerInfo(Class c) {
    System.out.println("類名: " + c.getName() +
      "是否接口? [" + c.isInterface() + "]");
  }
  public static void main(String[] args) {
    Class c = null;
    try {
      c = Class.forName("typeinfo.Derived");
    } catch (ClassNotFoundException e) {
      System.out.println("找不到Base類");
      System.exit(1);
    }
    printerInfo(c);
    Class up = c.getSuperclass(); // 取得c對象的基類
    Object obj = null;
    try {
      obj = up.newInstance();
    } catch (InstantiationException e) {
      System.out.println("不能實例化");
      System.exit(1);
    } catch (IllegalAccessException e) {
      System.out.println("不能訪問");
      System.exit(1);
    }
    printerInfo(obj.getClass());
  } /* 輸出:
  加載Base類
  加載Derived類
  類名: typeinfo.Derived是否接口? [false]
  類名: typeinfo.Base是否接口? [false]
  */
}

    Class intClass = int.class;
    Class<Integer> genericIntClass = int.class;
    genericIntClass = Integer.class; // 等價
    intClass = double.class; // ok
    // genericIntClass = double.class; // Illegal!

class Base {}
class Derived extends Base {}
class Base2 {}
public class Test {
  public static void main(String[] args) {
    Class<? extends Base> cc = Derived.class; // ok
    // cc = Base2.class; // Illegal
  } 
}

class Base {}
class Derived extends Base {}
public class Test {
  public static void main(String[] args) {
    Derived derived = new Derived();
    System.out.println(derived instanceof Base); // 輸出true
  } 
}

// 使用反射展示類的所有方法, 即使方法是在基類中定義的
package typeinfo;
// Print類的print方法等價于System.Out.Println，方便減少代碼量
import static xyz.util.Print.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.regex.Pattern;
// {Args: typeinfo.ShowMethods}
public class ShowMethods {
  private static String usage = 
    "usage:\n" +
    "ShowMethods qualified.class.name\n" +
    "To show all methods in class or:\n" +
    "ShowMethods qualified.class.name word\n" +
    "To search for methods involving 'word'";
  // 去掉類名前面的包名
  private static Pattern p = Pattern.compile("\\w+\\.");
  public static void main(String[] args) {
    if (args.length < 1) {
      print(usage);
      System.exit(0);
    }
    int lines = 0;
    try {
      Class<?> c = Class.forName(args[0]);
      // 反射獲得對象c所屬類的方法
      Method[] methods = c.getMethods();
      // 反射獲得對象c所屬類的構造
      Constructor[] ctors = c.getConstructors();
      if (args.length == 1) {
        for (Method method : methods)
          print(p.matcher(method.toString()).replaceAll(""));
        for (Constructor ctor : ctors)
          print(p.matcher(ctor.toString()).replaceAll(""));
      }
    } catch (ClassNotFoundException e) {
      print("No such class: " + e);
    }
  } /*
  public static void main(String[])
  public final void wait() throws InterruptedException
  public final void wait(long,int) throws InterruptedException
  public final native void wait(long) throws InterruptedException
  public boolean equals(Object)
  public String toString()
  public native int hashCode()
  public final native Class getClass()
  public final native void notify()
  public final native void notifyAll()
  public ShowMethods()
  */
}

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
class DynamicProxyHandler implements InvocationHandler {
  private Object proxied; // 代理對象
  public DynamicProxyHandler(Object proxied) {
    // TODO Auto-generated constructor stub
    this.proxied = proxied;
  }
  @Override
  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    // TODO Auto-generated method stub
    System.out.println("代理類: " + proxy.getClass() + "\n"
        + "代理方法: " + method + "\n"
        + "參數: " + args);
    if (args != null)
      for (Object arg : args)
        System.out.println(" " + arg);
    return method.invoke(proxied, args);
  }
}
interface Interface { void doSomething(); }

class RealObject implements Interface {
  
  @Override
  public void doSomething() {
    // TODO Auto-generated method stub
    System.out.println("doSomething");
  }
}
public class DynamicProxyDemo {
  public static void consumer(Interface iface) {
    iface.doSomething();
  }
  public static void main(String[] args) {
    RealObject realObject = new RealObject();
    // 使用動態(tài)代理
    Interface proxy = (Interface)Proxy.newProxyInstance(
        Interface.class.getClassLoader(),
        new Class[] { Interface.class }, 
        new DynamicProxyHandler(realObject));
    consumer(proxy);
  } /* 輸出：
  代理類: class $Proxy0
  代理方法: public abstract void Interface.doSomething()
  參數: null
  doSomething
  */
}