建造者模式

一、定义

建造者模式是将一个复杂的对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。创建者模式隐藏了复杂对象的创建过程，它把复杂对象的创建过程加以抽象，通过子类继承或者重载的方式，动态的创建复杂的、具有复合属性的对象。

二、例子

构造一个手机，手机包括CPU，内存，屏幕等几个部分，而CPU，内存，屏幕配置不同又有高端，低端之分。要求手机配置可以灵活搭配。

 

UML

三、 代码

 1.Program.cs

public class Program
    {
        static void Main(string[] args)
        {
            IPhoneBuilder phoneBuilder = new PhoneBuilder();
            Phone phone = phoneBuilder
                .BuildCpu(cpu => { cpu.Type = "8核16线程"; })
                .BuildMem(mem => { mem.Type = "32G"; })
                .BuildScreen(screen => { screen.Type = "10寸"; })
                .Build();
            phone.Show();
        }
    }

2.IPhoneBuilder.cs

 public interface IPhoneBuilder
    {
        IPhoneBuilder BuildCpu(Action<Cpu> buildCpuDelegate);
        IPhoneBuilder BuildMem(Action<Mem> buildMemDelegate);
        IPhoneBuilder BuildScreen(Action<Screen> buildScreenDelegate);
        Phone Build();
    }

3.PhoneBuilder.cs

public class PhoneBuilder:IPhoneBuilder
    {
        private Phone _phone;
        private Cpu _cpu;
        private Mem _mem;
        private Screen _screen;

        public IPhoneBuilder BuildCpu(Action<Cpu> buildCpuDelegate)
        {
            _cpu = new Cpu();
            buildCpuDelegate?.Invoke(_cpu);            
            return this;
        }

        public IPhoneBuilder BuildMem(Action<Mem> buildMemDelegate)
        {
            _mem = new Mem();
            buildMemDelegate?.Invoke(_mem);
            return this;
        }

        public IPhoneBuilder BuildScreen(Action<Screen> buildScreenDelegate)
        {
            _screen = new Screen();
            buildScreenDelegate?.Invoke(_screen);
            return this;
        }

        public Phone Build()
        {
            _phone = new Phone();
            _phone.Cpu = _cpu??new Cpu() { Type="4核8线程"};
            _phone.Mem = _mem ?? new Mem() { Type = "8G" };
            _phone.Screen = _screen ?? new Screen() { Type = "7寸" };
            return _phone;
        }
    }

4.Cpu.cs

 public class Cpu
    {
        public string Type { get; set; }
    }

5.Mem.cs

public class Mem
    {
        public string Type { get; set; }
    }

6.Screen.cs

public class Screen
    {
        public string Type { get; set; }
    }

7.Phone.cs

 public class Phone
    {
        public Cpu Cpu { get; set; }

        public Screen Screen { get; set; }

        public Mem Mem { get; set; }

        public void Show()
        {
            Console.WriteLine("手机配置:");
            Console.WriteLine($"CPU:{Cpu?.Type}");
            Console.WriteLine($"内存:{Mem?.Type}");
            Console.WriteLine($"屏幕:{Screen?.Type}");
        }
    }

四、运行结果