(a) Write the method getTotal() which returns the sum of the prices for all Item

Question

(a) Write the method getTotal() which returns the sum of the prices for all Items present in the ShoppingCart

Explanation / Answer

package cart; import entity.Product; import java.util.*; /** * * @author tgiunipero */ public class ShoppingCart { List items; int numberOfItems; double total; public ShoppingCart() { items = new ArrayList(); numberOfItems = 0; total = 0; } /** 031. * Adds a ShoppingCartItem to the ShoppingCart's * items list. If item of the specified product * already exists in shopping cart list, the quantity of that item is * incremented. * * @param product the Product that defines the type of shopping cart item * @see ShoppingCartItem */ public synchronized void addItem(Product product) { boolean newItem = true; for (ShoppingCartItem scItem : items) { if (scItem.getProduct().getId() == product.getId()) { newItem = false; scItem.incrementQuantity(); } } if (newItem) { ShoppingCartItem scItem = new ShoppingCartItem(product); items.add(scItem); } } /** * Updates the ShoppingCartItem of the specified * product to the specified quantity. If '0' * is the given quantity, the ShoppingCartItem is removed * from the ShoppingCart's items list. * * @param product the Product that defines the type of shopping cart item * @param quantity the number which the ShoppingCartItem is updated to * @see ShoppingCartItem */ public synchronized void update(Product product, String quantity) { short qty = -1; // cast quantity as short qty = Short.parseShort(quantity); if (qty >= 0) { ShoppingCartItem item = null; for (ShoppingCartItem scItem : items) { if (scItem.getProduct().getId() == product.getId()) { if (qty != 0) { // set item quantity to new value scItem.setQuantity(qty); } else { // if quantity equals 0, save item and break item = scItem; break; } } } if (item != null) { // remove from cart items.remove(item); } } } /** * Returns the list of ShoppingCartItems. * * @return the items list * @see ShoppingCartItem */ public synchronized List getItems() { return items; } /** * Returns the sum of quantities for all items maintained in shopping cart * items list. * * @return the number of items in shopping cart * @see ShoppingCartItem */ public synchronized int getNumberOfItems() { numberOfItems = 0; for (ShoppingCartItem scItem : items) { numberOfItems += scItem.getQuantity(); } return numberOfItems; } /** * Returns the sum of the product price multiplied by the quantity for all * items in shopping cart list. This is the total cost excluding the surcharge. * * @return the cost of all items times their quantities * @see ShoppingCartItem */ public synchronized double getSubtotal() { double amount = 0; for (ShoppingCartItem scItem : items) { Product product = (Product) scItem.getProduct(); amount += (scItem.getQuantity() * product.getPrice().doubleValue()); } return amount; } /** * Calculates the total cost of the order. This method adds the subtotal to * the designated surcharge and sets the total instance variable * with the result. * * @param surcharge the designated surcharge for all orders * @see ShoppingCartItem */ public synchronized void calculateTotal(String surcharge) { double amount = 0; // cast surcharge as double double s = Double.parseDouble(surcharge); amount = this.getSubtotal(); amount += s; total = amount; } /** * Returns the total cost of the order for the given * ShoppingCart instance. * * @return the cost of all items times their quantities plus surcharge */ public synchronized double getTotal() { return total; } /** * Empties the shopping cart. All items are removed from the shopping cart * items list, numberOfItems and * total are reset to '0'. * * @see ShoppingCartItem */ public synchronized void clear() { items.clear(); numberOfItems = 0; total = 0; } }

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.