Inheritance 2

abstract class Figure
{
    protected String color, type;
    protected int p;


    Observer obs = Observer.getInstance(5);



    public Figure(String color)
    {

        this.color = color;
    }

    abstract public double perimeter();

//     protected void Notify()
//     {
//         System.out.println(this);
//     }

    public void setColor(String s)
    {
        this.color = s;
        obs.Notify();
    }

    public boolean equals(Object o)
    {

        return (o instanceof Figure) && ((Figure)o).type.equals(this.type) &&
        ((Figure)o).perimeter() == this.perimeter();
    }

    public String toString()
    {
        return type + " " + color + " " + perimeter();
    }
}

//------------------------------------------------------------------------------
class Circle extends Figure
{
    private int radius;

    public Circle(int radius, String color)
    {

        super(color);
        type = "circle";
        this.radius = radius;
        obs.add(this);
    }

    public double perimeter()
    {
        return 2*3.14*radius;
    }

    public void setRadius(int x)
    {
        this.radius = x;
        obs.Notify();
    }


}

//-----------------------------------------------------------------------------------------
class Triangle extends Figure
{
    private int l1,l2,l3;

    public Triangle(int l1, int l2, int l3, String color)
    {

        super(color);
        type = "triangle";
        this.l1 = l1;
        this.l2 = l2;
        this.l3 = l3;
        obs.add(this);
    }

    public double perimeter()
    {
        return l1+l2+l3;
    }

    public void setLaturi(int x1, int x2, int x3)
    {
        this.l1 = x1;
        this.l2 = x2;
        this.l3 = x3;
        obs.Notify();
    }

}

//------------------------------------------------------------------------------
class Square extends Figure
{
    private int side;
    public Square(int side, String color)
    {

        super(color);
        type = "square";
        this.side = side;
        obs.add(this);
    }
    public double perimeter()
    {
        return 4*side;
    }

    public void setSide(int x)
    {
        this.side = x;
        obs.Notify();
    }

}

//------------------------------------------------------------------------------

class Observer
{
    private Figure vector[];
    private int capacity, i = 0,j;

    private static Observer observer = null;

    private Observer( int capacity)
    {
        this.capacity = capacity;
        vector = new Figure[capacity];
    }


    public boolean add(Figure figure_to_add)
    {
        if(i < capacity)
        {
            vector[i] = figure_to_add;
            i++;
            return true;
        }
        return false;
    }

    String buff = "";
    public String toString()
    {
        for(j = 0; j < i; j++)
        {
            buff += j+1 + ". " + vector[j] + "\n";
        }
        return buff;
    }

    public static Observer getInstance(int capacity) //o sa faca o noua instanta de observer doar daca actuala este nula, de aici o sa mearga la private constructor de sus si o sa puna capacity
    {
        if(observer == null)
            observer = new Observer(capacity);
        return observer;
    }

    public void Notify()
    {
        System.out.println(this);
    }

}

//------------------------------------------------------------------------------
class Main
{
    public static void main(String[] args)
    {
        Figure f1, f2, f3, f4, f5;
        f1 = new Circle(5, "yellow");
        f2 = new Triangle(1,2,3,"red");
        f3 = new Square(100, "blue");


      //  System.out.println(f1);
      //  System.out.println(f2);
      //  System.out.println(f3);

      //  ((Circle)f1).setRadius(8);
      //  ((Triangle)f2).setLaturi(4,5,6);
          ((Square)f3).setSide(10);


       // System.out.println(f1);
       // System.out.println(f2);
       // System.out.println(f3);





    }
}