design-patterns - 有人可以批评我的工厂模式吗？

Question

我最近一直在学习更多关于设计模式的知识，并想尝试一下。我不确定这是否是使用工厂模式的正确方法，并且想知道是否有人可以向我提供反馈？

我基本上有一组相似的日历项。膳食、锻炼和测量。它们都有日期和姓名，并且可以打印详细信息。但除此之外，他们还有一些他们各自需要的不同元素。

    public enum AppointmentType
{
    Workout,
    Meal,
    Measurement
}

public abstract class Appointment
{
    public string Name { get; set; }
    public DateTime DateStarted { get; set; }

    public virtual string PrintDetails()
    {
        return string.Format("Type: {0}\nName: {1}\nDate: {2}",this.GetType().ToString(), Name, DateStarted.ToShortDateString());
    }
}

public class Workout : Appointment
{
    public List<string> Exercises { get; set; }

    public Workout()
    {
        Exercises = new List<string>();
    }

    public override string PrintDetails()
    {
        string startInfo = base.PrintDetails();
        string addedInfo = "\nToday I will be doing the following:\n";

        foreach (string exercise in Exercises)
        {
            addedInfo += string.Format("{0}\n", exercise);
        }

        return startInfo + addedInfo;
    }
}

public class Meal : Appointment
{
    public List<string> FoodItems { get; set; }

    public Meal()
    {
        FoodItems = new List<string>();
    }

    public override string PrintDetails()
    {
        string startInfo = base.PrintDetails();
        string addedInfo = "\nToday I will be eating the following:\n";

        foreach (string foodItem in FoodItems)
        {
            addedInfo += string.Format("{0}\n", foodItem);
        }

        return startInfo + addedInfo;
    }
}

public class Measurement : Appointment
{
    public string Height { get; set; }
    public string Weight { get; set; }

    public override string PrintDetails()
    {
        string startInfo = base.PrintDetails();
        string addedInfo = string.Format("\nI am {0} feet tall and I weight {1} pounds!\n", Height, Weight);
        return startInfo + addedInfo;
    }
}

public interface IAppointmentFactory
{
    Appointment CreateAppointment(AppointmentType appointmentType);
}

public class AppointmentFactory : IAppointmentFactory
{
    public Appointment CreateAppointment(AppointmentType appointmentType)
    {
        switch (appointmentType)
        {
            case AppointmentType.Workout:
                return new Workout();
            case AppointmentType.Meal:
                return new Meal();
            case AppointmentType.Measurement:
                return new Measurement();
            default:
                return new Workout();
        }
    }
}

这是一个使用该库的程序:

  class Program
{
    public static List<Appointment> myAppointments;
    public static AppointmentFactory factory;
    public static Appointment myAppointment;

    static void Main(string[] args)
    {
        myAppointments = new List<Appointment>();
        factory = new AppointmentFactory();
        StartLoop();
    }

    private static void StartLoop()
    {
        Console.WriteLine(string.Format("\nWelcome to Appointment App: You have {0} appointment(s)!", myAppointments.Count()));
        Console.WriteLine("0 = Exit");
        Console.WriteLine("1 = New Workout");
        Console.WriteLine("2 = New Meal");
        Console.WriteLine("3 = New Measurement");
        Console.WriteLine("P = Print Schedule\n");

        switch (Console.ReadLine().ToUpper())
        {
            case "0":
                return;
            case "1":
                CreateNewAppointment(AppointmentType.Workout);
                AddExercises();
                break;
            case "2":
                CreateNewAppointment(AppointmentType.Meal);
                AddFoodItems();
                break;
            case "3":
                CreateNewAppointment(AppointmentType.Measurement);
                GetMeasurements();
                break;
            case "P":
                PrintSchedule();
                break;
            default:
                return;
        }

        StartLoop();
    }

    private static void GetMeasurements()
    {
        Console.WriteLine("How tall are you?");
        ((Measurement)myAppointment).Height = Console.ReadLine();
        Console.WriteLine("What is your weight?");
        ((Measurement)myAppointment).Weight = Console.ReadLine();
    }

    private static void AddFoodItems()
    {
        Console.WriteLine("How many food items do you want to add?");
        string exerciseCount = Console.ReadLine();

        for (int i = 0; i < Convert.ToInt32(exerciseCount); i++)
        {
            Console.WriteLine(string.Format("Food {0}:", (i + 1)));
            ((Meal)myAppointment).FoodItems.Add(Console.ReadLine());
        }
    }

    private static void AddExercises()
    {
        Console.WriteLine("How many exercises do you want to add?");
        string exerciseCount = Console.ReadLine();

        for (int i = 0; i < Convert.ToInt32(exerciseCount); i++)
        {
            Console.WriteLine(string.Format("Exercise {0}:", (i + 1)));
            ((Workout)myAppointment).Exercises.Add(Console.ReadLine());
        }
    }

    private static void PrintSchedule()
    {
        foreach (Appointment appointment in myAppointments)
        {
            Console.WriteLine(appointment.PrintDetails());
        }
    }

    public static void CreateNewAppointment(AppointmentType appointmentType)
    {
        myAppointment = factory.CreateAppointment(appointmentType);

        Console.WriteLine("Name:");
        myAppointment.Name = Console.ReadLine();
        Console.WriteLine("Start Date:");
        myAppointment.Name = Console.ReadLine();

        myAppointments.Add(myAppointment);
    }
}

谢谢!!

-ajax

Answer 1

下面是我要将其更改为:

public enum AppointmentType
{
    Workout,
    Meal,
    Measurement
}

public abstract class Appointment
{
    public string Name { get; set; }
    public DateTime DateStarted { get; set; }

    public abstract void PrintDetails();
    public abstract void RequestInputFromUser();
}

public class Workout : Appointment
{
    private List<string> Exercises { get; set; }

    public Workout()
    {
        Exercises = new List<string>();
    }

    public override void PrintDetails()
    {
        string startInfo = base.PrintDetails();
        string addedInfo = "\nToday I will be doing the following:\n";

        foreach (string exercise in Exercises)
        {
            addedInfo += string.Format("{0}\n", exercise);
        }

        Console.WriteLine(StartInfo + addedInfo);
    }

    public override void RequestInputFromUser()
    {
        Console.WriteLine("How many exercises do you want to add?");
        string exerciseCount = Console.ReadLine();

        for (int i = 0; i < Convert.ToInt32(exerciseCount); i++)
        {
            Console.WriteLine(string.Format("Exercise {0}:", (i + 1)));
            Exercises.Add(Console.ReadLine());
        }
    }
}

public class Meal : Appointment
{
    private List<string> FoodItems { get; set; }

    public Meal()
    {
        FoodItems = new List<string>();
    }

    public override void PrintDetails()
    {
        string startInfo = base.PrintDetails();
        string addedInfo = "\nToday I will be eating the following:\n";

        foreach (string foodItem in FoodItems)
        {
            addedInfo += string.Format("{0}\n", foodItem);
        }

        Console.WriteLine(startInfo + addedInfo);
    }

    public override void RequestInputFromUser()
    {
        Console.WriteLine("How many food items do you want to add?");
        string exerciseCount = Console.ReadLine();

        for (int i = 0; i < Convert.ToInt32(exerciseCount); i++)
        {
            Console.WriteLine(string.Format("Food {0}:", (i + 1)));
            FoodItems.Add(Console.ReadLine());
        }
    }
}

public class Measurement : Appointment
{
    private string Height { get; set; }
    private string Weight { get; set; }

    public override void PrintDetails()
    {
        string startInfo = base.PrintDetails();
        string addedInfo = string.Format("\nI am {0} feet tall and I weight {1} pounds!\n", Height, Weight);
        Console.WriteLine(startInfo + addedInfo);
    }

    public override void RequestInputFromUser()
    {
        Console.WriteLine("How tall are you?");
        Height = Console.ReadLine();
        Console.WriteLine("What is your weight?");
        Weight = Console.ReadLine();
    }
}

public interface IAppointmentFactory
{
    Appointment CreateAppointment(AppointmentType appointmentType);
}

public class AppointmentFactory : IAppointmentFactory
{
    public Appointment CreateAppointment(AppointmentType appointmentType)
    {
        Appointment apt;

        switch (appointmentType)
        {
            case AppointmentType.Workout:
                apt = new Workout();
            case AppointmentType.Meal:
                apt = new Meal();
            case AppointmentType.Measurement:
                apt = new Measurement();
            default:
                apt = new Workout();
        }

        Console.WriteLine("Name:");
        apt.Name = Console.ReadLine();
        Console.WriteLine("Start Date:");
        apt.Name = Console.ReadLine();    // Logic error on this line.
                                          // Change it to do what you mean.

        apt.RequestInputFromUser();

        return apt;
    }
}

使用它的代码如下:

class Program
{
    public static List<Appointment> myAppointments;
    public static AppointmentFactory factory;
    public static Appointment myAppointment;

    static void Main(string[] args)
    {
        myAppointments = new List<Appointment>();
        factory = new AppointmentFactory();
        StartLoop(factory);
    }

    private static void StartLoop(IAppointmentFactory factory)
    {
        bool exit = false;

        while(!exit)
        {

            Console.WriteLine(string.Format("\nWelcome to Appointment App: You have {0} appointment(s)!", myAppointments.Count()));
            Console.WriteLine("0 = Exit");
            Console.WriteLine("1 = New Workout");
            Console.WriteLine("2 = New Meal");
            Console.WriteLine("3 = New Measurement");
            Console.WriteLine("P = Print Schedule\n");

            switch (Console.ReadLine().ToUpper())
            {
                case "0":
                    exit = true;
                    break;
                case "1":
                    myAppointments.Add( factory.CreateAppointment( AppointmentType.Workout ) );
                    break;
                case "2":
                    myAppointments.Add( factory.CreateAppointment( AppointmentType.Meal ) );
                    break;
                case "3":
                    myAppointments.Add( factory.CreateAppointment( AppointmentType.Measurement ) );
                    break;
                case "P":
                    PrintSchedule();
                    break;
                default:
                    exit = true;
            }

        }

    }

    private static void PrintSchedule()
    {
        foreach (Appointment appointment in myAppointments)
        {
            appointment.PrintDetails();
        }
    }

}

需要注意的几件事:

• 下层的所有属性都是私有(private)的(好事)
• 没有类型转换(另一件好事)
• 很容易添加另一个约会类型(另一件好事)

仍有一些事情可以改变。具有公共(public)属性的基类仍然是一件坏事。但这是一个很大的改进。

我还删除了对 StartLoop() 的递归调用。当您只需要一个循环时，您不想增加堆栈。

编辑:对工厂类进行了一些更改。

回应评论:

• 要移除对控制台的依赖，请创建一个界面来表示您要对 IO 执行的操作。创建实现此接口(interface)的类并将实例发送到 Appointment 类。从那里，让一切都使用 IO 引擎的实例。要更改平台，请更改发送到约会类的 IO 实现类
• 公共(public)属性不好的原因与公共(public)变量不好的原因相同。一个类应该隐藏它的实现，而公共(public)属性公开它的实现。有关更多详细信息，我建议 Clean Code .它比我描述得更好。

总体来说还不错:)