curiostore2.java

来自「Java经典例程 从外国一大学计算机教授出版物下载的代码 经典」· Java 代码 · 共 95 行

class CurioStore2 {

  /* Polelo Curio Store No. 2        by J M Bishop April 2000
   * ------------------------
   * The shop with stock levels and a sell option
   * Illustrates methods in an object-oriented program
   */

  public static void main (String [ ] args) {
    // creates the class's (i.e. program's) object
    new CurioStore2 ();
  }

  // declare three objects
  Curio mugs, tshirts, carvings;

  // The constructor for the program
  // where the initialising and main work gets done
  CurioStore2 () {

     // instantiate the objects with different initial values
    mugs = new Curio("Traditional mugs", 6, "beaded in Ndebele style");
    tshirts = new Curio("T-shirts", 30, "sizes M to XL");
    carvings = new Curio("Masks", 80, "carved in wood");

    // print out a report
    report ();

    // Now stock the shop for each curio
    mugs.addToStock(10);
    tshirts.addToStock(50);
    carvings.addToStock(5);

    // Report on stock levels
    available ();

    // Sell something. The sell method returns a string with
	// a "receipt" we can print.
    System.out.println(tshirts.sell(8));

    // Report on stock levels again
    available ();
  }

  void report () {
    System.out.println("The Polelo Curio Store sells\n");
    // use the objects' access to toString to print their contents
    mugs.write();
    tshirts.write();
    carvings.write();
  }

  void available () {
    System.out.println("Available are "+mugs.stockLevel()+" "+
       tshirts.stockLevel()+" "+carvings.stockLevel()+
       " curios respectively\n");
  }
}

class Curio {
    // An inner class giving details of and actions on a curio.
    // Will be expanded as the project progresses.

    // Declare the fields, including a new one for stock
    String item;
    int price;
    String description;
    int stock = 0;

    // The constructor copies the initialisation into the fields
    Curio (String n, int p, String d) {
      item = n;
      price = p;
      description = d;
    }

    // Three new actions available on curios
    void addToStock (int n) {
      stock += n;
    }

    String sell (int n) {
      stock -= n;
      return "Sold " + n + " " + item;
    }

    int stockLevel () {
      return stock;
    }

    void write () {
      System.out.println(item + " " + description + " for G" + price);
    }
  }