// Mixing.java
// demonstrates encapsulation, $static$
// Originally written by Raju Rohde, Fall 2000

/*  
   This is an example on how to write static/non-static methods 
   and how you can pass reference variables to methods

   Write a class Juice that is has
   1. instance variables:
      o vol    (volume)
      o sugar  (amount of sugar in % of vol)
      o water  (amount of water in % of vol)
   2. constructor that initializes the instance variables
   3. instance method, mix1, that mixes one's juice with another
      juice and returns a new juice
   4. class method, mix2, that mixes two jucies and returns
      a new juice

   Write a class Mixing that
   1. instantiates 2 objects of class Juice (assign some 
      reasonable numbers to the instance variable)
   2. "mix" those 2 instantiates juices by calling both
      the instance  method mix1 and the class method mix2.
  
   Note: Juices produced by methods mix1 and mix2 should taste 
         the same.
*/

class Juice{
    // instance variables
    private double vol;
    private double sugar;
    private double water;

    // constructor
    public Juice(double v, double s, double w) {
	vol=v;
	sugar=s;
	water=w;
    }

    // getters
    public double getVolume() { return vol;   }
    public double getSugar()  { return sugar; }
    public double getWater()  { return water; }

    // instance method approach: mix ingredients
    // Mix current Juice's ingredients and with another Juice's ingredients:
    public Juice mix1(Juice j){
	double volmix= j.vol + vol;
	double sugmix= (j.sugar + sugar)/volmix;
	double watmix= (j.water + water)/volmix;
	return new Juice(volmix,sugmix,watmix);
    }

    // class method: mix ingredients
    // Mix 2 Juice's ingredients together:
    public static Juice mix2(Juice j1,Juice j2){
	double volmix= j1.vol + j2.vol;
	double sugmix= (j1.sugar + j2.sugar)/volmix;
	double watmix= (j1.water + j2.water)/volmix;
	return new Juice(volmix,sugmix,watmix);
    }
}

class Mixing{
    public static void main(String [] args){

	// Instantiate two "reasonable" drinks of class Juice:
	Juice drink1=new Juice(100,30,70);
	Juice drink2=new Juice(150,40,110);

	// Instantiate first mix by calling the instance method:
	Juice mixdrink1=drink1.mix1(drink2);
	System.out.println("mixdrink1: vol  = " + mixdrink1.getVolume() );
	System.out.println("           sugar= " + mixdrink1.getSugar()  );
	System.out.println("           water= " + mixdrink1.getWater()  );

	// Instantiate second mix by calling the class method:
	Juice mixdrink2=Juice.mix2(drink1,drink2);
	System.out.println("mixdrink2: vol  = " + mixdrink2.getVolume() );
	System.out.println("           sugar= " + mixdrink2.getSugar()  );
	System.out.println("           water= " + mixdrink2.getWater()  );
    }
}


/* Output:
mixdrink1: vol  = 250.0
           sugar= 0.28
           water= 0.72
mixdrink2: vol  = 250.0
           sugar= 0.28
           water= 0.72
*/