sell.java

这是一个面向对象编程教学案例的设计,同时附带一个餐厅计费程序的例子,并用java实现.同时附带类框图,说明模型的关系.

                return "鸡排";
            case Corn:
                return "玉米";
            default:
                return "";
        }
    }

}

enum Eum_SeaFood
{
    Conch("201", 50), // 扇贝
    Lobster("202", 120), // 龙虾
    Crab("203", 150); // 螃蟹

    String id;

    double price;

    Eum_SeaFood(String id, double price)
    {

        this.id = id;
        this.price = price;
    }

    public String toString()
    {

        switch (this)
        {
            case Conch:
                return "扇贝 ";
            case Lobster:
                return "龙虾";
            case Crab:
                return "螃蟹";
            default:
                return "";
        }
    }

}

enum Eum_WineFood
{
    Aquavit("301", 30), // 白兰地
    Champagne("302", 35), // 香槟酒
    Beer("303", 10); // 啤酒

    String id;

    double price;

    Eum_WineFood(String id, double price)
    {

        this.id = id;
        this.price = price;
    }

    public String toString()
    {

        switch (this)
        {
            case Aquavit:
                return "白兰地 ";
            case Champagne:
                return "香槟酒";
            case Beer:
                return "啤酒";
            default:
                return "";
        }
    }

}

// 食品对象工厂
class Factory
{

    public static FoodStuff createNormalFood(String id, String name,double price)
    {

        return new NormalFood(id, name, price);
    }

    public static FoodStuff createSeaFood(String id, String name, double price)
    {

        return new SeaFood(id, name, price);
    }

    public static FoodStuff createWineFood(String id, String name, double price)
    {

        return new WineFood(id, name, price);
    }

    public static FoodStuff createFood(String id)
    {

        char flag = id.charAt(0);
        switch (flag)
        {
            case '1':
                return createNormalFoodById(id);
            case '2':
                return createSeaFoodById(id);
            case '3':
                return createWineFoodById(id);
            default:
                return null;
        }
    }

    private static FoodStuff createNormalFoodById(String id)
    {

        for (Eum_NormalFood normal : Eum_NormalFood.values())
        {
            if (normal.id.equals(id))
            {
                return createNormalFood(normal.id, normal.toString(),
                        normal.price);
            }
        }
        return null;
    }

    private static FoodStuff createSeaFoodById(String id)
    {

        for (Eum_SeaFood sea : Eum_SeaFood.values())
        {
            if (sea.id.equals(id))
            {
                return createSeaFood(sea.id, sea.toString(), sea.price);
            }
        }
        return null;
    }

    private static FoodStuff createWineFoodById(String id)
    {

        for (Eum_WineFood wine : Eum_WineFood.values())
        {
            if (wine.id.equals(id))
            {
                return createWineFood(wine.id, wine.toString(), wine.price);
            }
        }
        return null;
    }
}

interface Input
{
    public Map<String, Integer> getConsumeINF(Menu menu);

    public String getDiscountINF();

    public boolean getContinueState();
}

interface Output
{
    public void prtBill(List<FoodStuff> consumeList, double account,
            Map<String, Double> discountMap, double payment);

    public void prtMenu(Map<String, FoodStuff> menuMap) ;
}

class BillIO implements Input, Output
{

    public void prtBill(List<FoodStuff> consumeList, double account,
            Map<String, Double> discountMap, double payment)
    {

        prtBillTitle();
        prtCousumeContent(consumeList);
        prtAccount(account);
        prtBillDiscount(discountMap);
        prtPayment(payment);
    }

    public void prtMenu(Map<String, FoodStuff> menuMap) {
        final String MSG="菜 单：";
    prtInformation(MSG);
    for (String str : menuMap.keySet()) {
    FoodStuff food = menuMap.get(str);
    prtInformation(food.getId(),food.getName(),food.getPrice());
    }
    }

    public Map<String, Integer> getConsumeINF(Menu menu)
    {

        Map<String, Integer> inputMap;
        final String errMsg = "消费食品的代码不正确，请重新输入！";
        while (true)
        {
            inputMap = getInputMap(menu);
            if (inputMap != null)
                return inputMap;

            prtInputErrMsg(errMsg);
            continue;
        }

    }

    public String getDiscountINF()
    {

        final String MSG1 = "您享受进餐等待优惠吗？（Y/N）";
        final String MSG2 = "您享受VIP优惠吗？（Y/N）";
        StringBuffer sbf = new StringBuffer();
        sbf.append(getState(MSG1));
        sbf.append(" ");
        sbf.append(getState(MSG2));
        sbf.append(" ");
        sbf.append(getToken());
        return sbf.toString();
    }

    public boolean getContinueState()
    {

        final String MSG = "继续计算食品消费吗？（Y/N）";
        prtWhiteRow();
        return (getState(MSG) == 1) ? true : false;
    }

    private void prtBillTitle()
    {

        final String MSG = "您消费了以下的食品：";
        prtInformation(MSG);
    }

    private void prtCousumeContent(List<FoodStuff> consumeList)
    {

        for (FoodStuff food : consumeList)
        {
            prtInformation(food.getId(), food.getName(), food.getPrice());
        }
    }

    private void prtAccount(double account)
    {

        final String MSG = "您消费的总金额";
        prtInformation(MSG, account);
    }

    private void prtBillDiscount(Map<String, Double> discountMap)
    {

        final String MSG = "您享受的折扣如下：";
        prtInformation(MSG);
        for (String str : discountMap.keySet())
        {
            prtInformation(str, discountMap.get(str));
        }
    }

    private void prtPayment(double payment)
    {

        final String MSG = "你需要支付的金额";
        prtInformation(MSG, payment);
    }

    private Map<String, Integer> getInputMap(Menu menu)
    {
        
        Map<String, Integer> consumeMap = new HashMap<String, Integer>();
        Map<String,FoodStuff> menuMap=menu.getMenuMap();
        Scanner sc = new Scanner(getInputStr());

        while (sc.hasNext())
        {
            String str = sc.next();
            String id = str.substring(0, 3);
            if (!menuMap.containsKey(id))
            {
                return null;
            }

            Integer num = new Integer(str.substring(3));
            if (consumeMap.get(id) == null)
            {
                consumeMap.put(id, num);
            }
            else
            {
                consumeMap.put(id, consumeMap.get(id) + num);
            }

        }
        return consumeMap;
    }

    private String getInputStr()
    {

        final String pattern = "\\d{5}|\\d{5}(\\s+\\d{5})+";
        final String errMsg = "消费食品的输入格式不正确，请重新输入！";
        String inputStr;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while (true)
        {
            prtInputMsg();
            try
            {
                inputStr = br.readLine();
                if (inputStr.trim().matches(pattern))
                    return inputStr;
                else
                {
                    prtInputErrMsg(errMsg);
                    continue;
                }
            }
            catch (IOException e)
            {
                e.getStackTrace();
            }

        }
    }

    private int getState(String msg)
    {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while (true)
        {
            System.out.println(msg);
            try
            {
                String state = br.readLine();
                if (state.equals("Y") || state.equals("y"))
                {
                    return 1;
                }
                if (state.equals("N") || state.equals("n"))
                {
                    return 0;
                }
            }
            catch (IOException e)
            {
                e.getStackTrace();
            }
            continue;
        }
    }

    private double getToken()
    {
        final String MSG = "您使用代金券的金额：(整数)";
        while (true)
        {
            prtInformation(MSG);
            try
            {
                BufferedReader br = new BufferedReader(new InputStreamReader(
                        System.in));
                String str = br.readLine();
                if (str.matches("[0-9]*"))
                {
                    if (str.equals(""))
                        return 0;
                    return new Double(str).doubleValue();
                }
                continue;
            }
            catch (IOException e)
            {
                e.getStackTrace();
            }
        }
    }

    private void prtInputMsg()
    {

        final String InputNotice1 = "消费信息输入格式：xxxxx（前三位是消费品编号，后两位是消费品数量）；不同种类的消费品间用一个空格分隔；";
        final String InputNotice2 = "消费的信息输入：";
        prtInformation(InputNotice1);
        prtInformation(InputNotice2);
    }

    private void prtInformation(String id, String name, double price)
    {

        System.out.println(id + "  " + name + "  " + price);
    }

    private void prtInformation(String msg, double discount)
    {

        System.out.println(msg + ":" + discount);
    }

    private void prtInformation(String msg)
    {

        System.out.println(msg);
    }

    private void prtInputErrMsg(String errMsg)
    {

        prtInformation(errMsg);
        prtWhiteRow();
    }

    private void prtWhiteRow()
    {
        System.out.println(" ");
    }
}