import java.io.*;
import java.net.*;
import java.util.*;

class student 
{
    public final String name;
    private double gpa;  // note private
    public student(String n)
    {
	name=n; 
	gpa = ((int)(Math.random()*401))/100.0;
    }
    public String toString() { return "student "+name+" has a "+gpa+" GPA"; }

    public void run()
    { System.out.println("huff and puff..."); }
}

class vehicle
{
    public final String make;
    public final String model;
    public final int year;
    public int price = 30000;
    public vehicle(String b, String m, int y) {make=b; model=m; year=y;}
    public String toString() {return year+" "+make+" "+model;}

    public void run()
    { System.out.println("zoom zoom"); }
}//vehicle


class pc
{
    public final String cpu;
    public int RAM;  // in GB
    public int Storage;  // in TB
    public int price = 1000;
    public pc(String c, int r, int s)
    { cpu=c;  RAM=r;  Storage=s; }
    public void run()
    { throw new RuntimeException("Segmentation Fault. Core Dumped"); }
}

// Cross cutting aspects of the program:

aspect trace // trace the construction of each object, plus run function
{
    // after advice
    after(Object c) : (execution(student+.new(..)) ||
		       execution(pc.new(..)) || execution(vehicle.new(..)))
	&& target(c) && !adviceexecution()
	{
	    System.out.println("Object created: "+c );
	}
}//trace


// aspect Autoretry
aspect FaultTolerance
{
    private static int max = 3;
    public static void setmax(int m)  {max=m;}
    void around(Object c): call(void *.run()) && target(c)
    {
	int cx = max; // allow 3 attempts to run
	while (cx-->0)
	    {
		try
		    {
			proceed(c); // proceed with run() on target c
			cx = 0; // stops while loop
		    }
		catch (RuntimeException re)
		    {
			if (cx==0)
			   System.out.println("run failed after "+max+" tries");
		    }
	    }//while
    }//around advice
}

// censorship advice
aspect WholesomeOutput
{
    void around(String s):call( void PrintStream+.print*(..)) && args(s,..)
    {
	s = s.replaceAll("hell","heck");
	s = s.replaceAll("damn","darn");
	s = s.replaceAll("Liang is bad","Liang is badass");
	proceed(s);
    }
}


public class aop17
{
    public static void main(String[] av)
    {
	System.out.println("What the hell is going on!");
	
	student s = new student("Farman Imal");
	vehicle v = new vehicle("Honda","Accord",2008);
	pc yourpc = new pc("intel i7",16,5); // 16gb ram, 5tb disk
	s.run();
	v.run();
	yourpc.run();
    }//main
}


// Real extension methods, supporting dynamic dispatch

class studentathlete extends student
{
    String sport = "basketball";
    public studentathlete(String n) { super(n); }
    public void run() { System.out.println("whoooosh!"); }
}


// aspect to add new method to both student and studentahlete
interface stuinterface
{
    int tuition(); 
}

privileged aspect extendstudent  // privileged can access private fields
{
    declare parents: student implements stuinterface;
    // now *obligated* to extend student classes

    public int student.tuition()
    {
	if (this.gpa>3.7) return 10000; // scholarship student
	else return 40000;
    }
    public int studentathlete.tuition()
    { return 0; } // all student athletes are on scholarship

    // changing main without changing main...
    after() : execution(public static void *.main(String[]))
	{
	    student s1 = new studentathlete("Farma Nimal");
	    System.out.println(s1.tuition()); // dynamic dispatch? YES
	}
}//extendstudent privileged aspect