www.pudn.com > bookstore_new.rar > ShoppingCart.java

package mypack; 
 
import java.util.*; 
import java.io.Serializable; 
 
public class ShoppingCart implements Serializable{ 
  HashMap items = null; 
  int numberOfItems = 0; 
 
  public ShoppingCart() { 
      items = new HashMap(); 
  } 
 
  public synchronized void add(String bookId, BookDetails book) { 
    if(items.containsKey(bookId)) { 
        ShoppingCartItem scitem = (ShoppingCartItem) items.get(bookId); 
        scitem.incrementQuantity(); 
    } else { 
        ShoppingCartItem newItem = new ShoppingCartItem(book); 
        items.put(bookId, newItem); 
    } 
 
    numberOfItems++; 
  } 
 
  public synchronized void remove(String bookId) { 
    if(items.containsKey(bookId)) { 
        ShoppingCartItem scitem = (ShoppingCartItem) items.get(bookId); 
        scitem.decrementQuantity(); 
 
        if(scitem.getQuantity() <= 0) 
            items.remove(bookId); 
 
        numberOfItems--; 
    } 
  } 
 
  public synchronized Collection getItems() { 
      return items.values(); 
  } 
 
  protected void finalize() throws Throwable { 
      items.clear(); 
  } 
 
  public synchronized int getNumberOfItems() { 
      return numberOfItems; 
  } 
  public synchronized double getTotal() { 
    double amount = 0.0; 
 
    for(Iterator i = getItems().iterator(); i.hasNext(); ) { 
        ShoppingCartItem item = (ShoppingCartItem) i.next(); 
        BookDetails bookDetails = (BookDetails) item.getItem(); 
 
        amount += item.getQuantity() * bookDetails.getPrice(); 
    } 
    return roundOff(amount); 
  } 
 
  private double roundOff(double x) { 
      long val = Math.round(x*100); // cents 
      return val/100.0; 
  } 
 
  public synchronized void clear() { 
      items.clear(); 
      numberOfItems = 0; 
  } 
}