source: src/main/java/negotiator/onetomany/domain/Stack.java@ 239

/**
 * Stack class
 */
package negotiator.onetomany.domain;

/**
 * Stack contains a number of Chips 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() 
        {
                setChip(null);
                setQuantity(-1);
        }

        public Stack(Chip c, int q)
        {
                setChip(c);
                setQuantity(q);
        }

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

        /**
         * @param chip the chip to set
         */
        public void setChip(Chip chip) 
        {
                this.chip = chip;
        }

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

        /**
         * @param quantity the quantity to set
         */
        public void setQuantity(int quantity) 
        {
                this.quantity = quantity;
        }

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

        public Stack aggregateWith(Stack s) 
        {
                if (this!=null && s!=null && chip.getColor()==s.getChip().getColor()) 
                        return new Stack(new Chip(getChip().getColor(), (getChip().getPrice()*quantity+s.getChip().getPrice()*s.getQuantity())/(quantity+s.getQuantity())),quantity+s.getQuantity());
                else 
                {
                        System.out.println("\n\n[Warning] StackClass::aggregateWith(Stack). Different colors! Aggregating "+s+" into "+this+" is not possible; stack "+this+" remained unchanged!");
                        return this;
                }
        }
                        

        @Override
        public String toString() 
        {
                return getQuantity()+" x "+getChip();
                // two other representations:
                //return this.getClass().getSimpleName()+"("+getChip()+","+getQuantity()+")"
                //return this.getClass().getSimpleName()+"("+getQuantity()+" x "+getChip()+")";
        }
}