模型

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在这里，将工厂类去掉，但是抽象出来Client接口，并让3个具体的工厂方法去实现这个接口。也就是说，用子类的Client8085,Client8080,Client8086去决定实例化哪一个类。通过这样的改动，将一个类的实例化延迟到了其子类。

代码如下：

namespace 生产CPU
{
    public class Cpu8086 : CPU  //8086CPU
    {
        public Cpu8086()
        {
            this.size = "8086";
            Console.WriteLine("生产的是8086CPU。");
        }


    }

    public class Cpu8080 : CPU  //8080CPU
    {
        public Cpu8080()
        {
            this.size = "8080";
            Console.WriteLine("生产的是8080CPU。");
        }


    }

    public class Cpu8085 : CPU  //8085CPU
    {
        public Cpu8085()
        {
            this.size = "8085";
            Console.WriteLine("生产的是8085CPU。");
        }


    }


    public class CPU  //CPU类
    {
        private string Size;

        public string size
        {
            get { return Size; }
            set { Size = value; }
        }


    }
     
    interface Client   //定义一个选择生产CPU的接口（客户的抽象）
    {
        CPU ChooseCpu();

    }

    class Client8086 : Client   //生产8086CPU的工厂类
    {
        public CPU ChooseCpu()
        {
            return new Cpu8086();
        }
    }

    class Client8085 : Client  //生产8085CPU的工厂类
    {
        public CPU ChooseCpu()
        {
            return new Cpu8085();
        }
    }

    class Client8080 : Client   //生产8080CPU的工厂类
    {
        public CPU ChooseCpu()
        {
            return new Cpu8080();
        }
    }


    class Program
    {
        static void Main(string[] args)
        {
            Client client = new Client8080();  //生产8080CPU
            CPU CpuType = client.ChooseCpu();   
        }
    }
}

工厂方法虽然增加了额外的类，但是这样做是有好处的，例如：