《大话设计模式》学习笔记9：建造者模式

　　

　　

建造小人示例：

　　

1.Builder：

    public abstract class PersonBuilder
    {
        public abstract void BuildHead();
        public abstract void BuildBody();
        public abstract void BuildArm();
        public abstract void BuildLeg();
    }

2.ConcreteBuilder：

    public class ThinPersonBuilder:PersonBuilder
    {
        public override void BuildHead()
        {
            Console.WriteLine("瘦头");
        }

        public override void BuildBody()
        {
            Console.WriteLine("瘦身体");
        }

        public override void BuildArm()
        {
            Console.WriteLine("瘦手");
        }

        public override void BuildLeg()
        {
            Console.WriteLine("瘦腿");
        }
    }

    public class FatPersonBuilder:PersonBuilder
    {
        public override void BuildHead()
        {
            Console.WriteLine("胖头");
        }

        public override void BuildBody()
        {
            Console.WriteLine("胖身体");
        }

        public override void BuildArm()
        {
            Console.WriteLine("胖手");
        }

        public override void BuildLeg()
        {
            Console.WriteLine("胖腿");
        }
    }

3.Director：

    public class PersonDirector
    {
        private PersonBuilder personBuilder;
        public PersonDirector(PersonBuilder personBuilder)
        {
            this.personBuilder=personBuilder;
        }
        public void CreatePerson()
        {
            personBuilder.BuildHead();
            personBuilder.BuildBody();
            personBuilder.BuildArm();
            personBuilder.BuildLeg();
        }
    }

4.客户端代码：

    class Program
    {
        static void Main(string[] args)
        {
            PersonBuilder thinPersonBuilder = new ThinPersonBuilder();
            PersonDirector thinPersonDirector = new PersonDirector(thinPersonBuilder);
            thinPersonDirector.CreatePerson();

            PersonBuilder fatPersonBuilder = new FatPersonBuilder();
            PersonDirector fatPersonDirector = new PersonDirector(fatPersonBuilder);
            fatPersonDirector.CreatePerson();
        }
    }

　　建造者模式的好处是使得建造代码与表示代码分离，由于建造者隐藏了该产品是如何组装的，所欲若需要改变一个产品的内部表示，只需要再定义一个具体的建造者就可以了。