basket.java

这是一个买卖系统,一个模拟的系统,根据下订单,看订单,买,等功能

package Catalogue;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Locale;
import java.util.Formatter;
import java.util.Currency;


public class Basket implements Serializable
{
  private static final long serialVersionUID = 1;
  private ArrayList<Product> theContents = new ArrayList<Product>(10);
  
  /**
   * Adds a product to the Basket
   */

  public void add( Product pr )    // Add a product to the
  {                                //  product list
    theContents.add( pr );         //
  }

  /**
   * Returns the number of products in the basket.
   * @return number of products
   */

  public int number()              // Return the number of
  {                                //  entries in the
    return theContents.size();     //  product list
  }

  /**
   * 
   */

  public Product remove()          // Remove and return last item
  {
    int items = theContents.size();
    if ( items < 1 ){
      throw new Error("EMPTY: Basket.remove()");
    }
    return theContents.remove( items-1 );
  }

  /**
   * Clear the list. All items stored are removed.
   */

  public void clear()              // Clear the
  {                                // the product list
    theContents.clear();
  }

  /**
   * Returns an array of the held products.
   * @return array of held products
   */

  public Product[] products()      // Return array of products
  {
    Product results[] = new Product[theContents.size()];  // Result array
    return theContents.toArray( results );                // return
  }

  /**
   * Returns a string containing a description of all the products held.
   * @return string description of products
   */

  public String details()          // Return list of products as string
  {
    Locale uk = Locale.UK;
    StringBuilder sb = new StringBuilder(256);
    Formatter     fr = new Formatter(sb, uk);
    String csign = (Currency.getInstance( uk )).getSymbol();
    double total = 0.00;
    for ( Product pr: theContents )
    {
      int     no = pr.getQuantity();
      fr.format("%-7s",       pr.getProductNo() );
      fr.format("%-14.14s ",  pr.getDescription() );
      fr.format("(%d) ",      no );
      fr.format("%s%7.2f",    csign, pr.getPrice()*no );
      fr.format("\n");
      total += pr.getPrice() * no;
    }
    fr.format("--------------------------\n");
    fr.format("Total                     ");
    fr.format("%s%7.2f\n",    csign, total );
    return sb.toString();
  }
}