source: src/main/java/onetomany/bargainingchipsgame/Stack.java@ 266

package onetomany.bargainingchipsgame;

/**
 * Stack contains a number of {@link Chip} objects of the same color and price. 
 * A stack=(chip, quantity). 
 * Aggregation of a two stacks of the same colors, creates another stack with the total quantity but its chip in a new price equal to weighted average of the both unit prices.  
 * Aggregation of a stack with the empty stack is itself.  
 * 
 * @author Faria Nassiri-Mofakham
 *
 */
public class Stack 
{
        private Chip chip;
        private int quantity;

        public Stack(Chip c, int q)
        {
                chip = c;
                quantity = q;
        }
        
        public Stack(String color, double price, int qty)
        {
                chip = new Chip(color, price);
                quantity = qty;
        }

        /**
         * @return the chip
         */
        public Chip getChip() {
                return chip;
        }

        /**
         * @return the quantity
         */
        public int getQuantity() 
        {
                return quantity;
        }

        public double getPrice()
        {
                return chip.getPrice()*quantity;
        }

        public String getColor()
        {
                return chip.getColor();
        }
        
        public boolean hasSameColorAs(Stack s)
        {
                return getColor().equals(s.getColor());
        }
        
        public Stack aggregateWith(Stack s) 
        {
                if (s!=null && chip.hasSameColorAs(s)) {
                        String color = getChip().getColor();
                        double p = (getChip().getPrice()*quantity+s.getChip().getPrice()*s.getQuantity())/(quantity+s.getQuantity());
                        return new Stack(new Chip(color, p), quantity + s.getQuantity());
                } else 
                        throw new IllegalStateException("\n\n[Warning] StackClass::aggregateWith(Stack). Different colors! Aggregating "+s+" into "+this+" is not possible.");
        }       

        @Override
        public String toString() 
        {
                return getQuantity()+" x "+getChip();
        }
        
        public static void main(String[] args) 
        {
                Stack s = new Stack("Red", 9.0, 3);
                Stack t = new Stack ("Red", 4.0, 2);
                System.out.println(s + " + " + t + " = " + s.aggregateWith(t));
                System.out.println(t + " + " + s + " = " + t.aggregateWith(s));         
        }
}