shoppingcart.java

完整的网上商城程序

package mypack;

import java.util.*;

public class ShoppingCart
{
  HashMap items=null;
  int numberOfItem=0;

  public ShoppingCart()
  {
    items=new HashMap();
  }

  public synchronized void add(String ticketId, TicketDetails ticket)
  {
    if(items.containsKey(ticketId))
    {
      ShoppingCartItem scitem=(ShoppingCartItem)items.get(ticketId);
      scitem.incrementQty();
    }
    else
    {
      ShoppingCartItem newItem=new ShoppingCartItem(ticket);
      items.put(ticketId, newItem);
      numberOfItem++;
    }

    
  }

  public synchronized void remove(String ticketId)
  {
    if(items.containsKey(ticketId))
    {
      ShoppingCartItem scitem=(ShoppingCartItem)items.get(ticketId);
      scitem.decrementQty();

      if(scitem.getQty()<=0)
      {
      
        items.remove(ticketId);

      numberOfItem--;
      }
    }
  }

  public synchronized Collection getItems()
  {
    return items.values();
  }

  public void finalize() throws Throwable
  {
    items.clear();
  }

  public synchronized int getNumberOfItem()
  {
    return numberOfItem;
  }

  public synchronized double getTotal()
  {
    double amount=0.0;

    for(Iterator i=getItems().iterator();i.hasNext();)
    {
      ShoppingCartItem item=(ShoppingCartItem)i.next();
      TicketDetails ticketDetails=(TicketDetails)item.getItem();

      amount+=item.getQty()*ticketDetails.getPrice();
    }
    return roundOff(amount);
  }

  private double roundOff(double x)
  {
    long val=Math.round(x*100);
    return val/100.0;
  }

  public synchronized void clear()
  {
    items.clear();
    numberOfItem=0;
  }
}