Toppings Catalog (With Per-Serving Cost in units)

Business Rules that your system must follow:

1. Cheeseburst Tax Uplift
   • Cheeseburst is considered unhealthy food and attracts more tax.
     If at least one serving of cheeseburst is present, increase the pizza’s entire tax rate by +30% of its current value (one-time uplift).
   • Example: base tax 10 → 10 + 0.30 × 10 = 13.
   • Additional cheeseburst servings do not further change tax.
2. Cheeseburst Volume Discount
   • First serving costs 100; each additional serving costs 70.
3. Health Constraint (Mutual Exclusion)
   • mushroom is considered healthy food and it cannot be added if cheeseburst is already present, also cheeseburst cannot be added if mushroom is already present.
   • On violation, addTopping returns false and there is no state change.

Your implementation should make it easy to add new rules later (for example, size-based caps, combos, promos) .
Use decorator design pattern .

Constructor and Methods

PizzaPricing(int basePrice, int taxPercentage, String size)
		

• 100 ≤ basePrice ≤ 10000, and basePrice will always be a multiple of 100.
  
  
• 0 ≤ taxPercentage ≤ 1000 1000% tax means tax is 10 times the base price of pizza.
  i.e. if base price is 200 units and tax 1000 and no toppings are there,
  then final price = 200+ tax = 200* 1000% of 200 = 200 + 1000/100 * 200 = 2,200/- units
  Another example: basePrice = 200 units, taxPercentage = 18% then,
  Final price = 200 + 18/100 * 200 =200+36 = 236 units.
  
  
• size is one of small, medium, large.
  
  
• All constructor inputs are guaranteed to be valid.

Methods

• boolean addTopping(String topping, int servingsCount)
  • servingsCount is a valid positive integer.
  • Returns true if the topping is applied (passes all rules); otherwise false and no state change.
• int getFinalPrice()
  • Returns the final price rounded to int using Round Half Up (see rounding).
  • Can be called any time.

Pricing and Tax Model

• Subtotal = basePrice + Σ(topping costs actually applied)
• Taxable Base = Subtotal
• Tax Rate starts at the constructor-supplied taxPercentage. Rules can make it fractional (for example, +30% of current tax).
• Tax Amount = (Tax Rate / 100) × Subtotal
• Final Price (pre-round) = Subtotal + Tax Amount

Final price Rounding Rule

To convert final price to int: (int)(x + 0.5).

• 4.6 → 5; 4.51 → 5; 4.49 → 4; 4.5 → 5

Worked Examples

Example A - Uses all methods; cheeseburst uplift + other toppings

 Create pizza
	PizzaPricing p = new PizzaPricing(200, 10, "small");

	 Add toppings
	p.addTopping("cheeseburst", 1);   // true, tax 10 → 13 (one-time uplift)
	p.addTopping("onion", 2);         // true

	Compute final price
	int price = p.getFinalPrice();    // 407

	 Calculation: base=200; toppings=100 + 2×30=160; subtotal=360;
	 tax=13% of 360=46.8; final=406.8 → round half up ⇒ 407
	 

Example B - Mutual exclusion blocks cheeseburst

   Create pizza
	PizzaPricing q = new PizzaPricing(350, 8, "medium");

	 Add toppings
	q.addTopping("mushroom", 2);      // true (2×40=80)
	q.addTopping("cheeseburst", 1);   // false (blocked by mutual exclusion)

	 Compute final price
	int price = q.getFinalPrice();    // 464

	 Calculation: base=350; toppings=80; subtotal=430;
	 tax=8% of 430=34.4; final=464.4 → round half up ⇒ 464