Core Design Patterns(3) Bridge 桥接模式

VS 2008

桥接模式将抽象与实现分离
使得抽象和实现自称体系，可以独立变化

1. 模式UML描述



2. 应用

    想象在一个软件公司里，雇用了两类程序员：高级程序员，初级程序员。不同级别的程序员每年为公司创造的价值不同。又由于一些客观条件的不同，程序员为公司创造价值这个行为也不是一成不变的。为了隔离变化，将创造价值这个行为抽出来。形成如下的类图：




Programmer

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DesignPattern.Bridge.BLL {
    abstract class Programmer {

        protected string name;
        protected IProfitCreator profitCreator;

        public Programmer(string name) {
            this.name = name;
        }
        public virtual string GetName() {
            return this.name;
        }
        public void SetProfitCreator(IProfitCreator profitCreator) {
            this.profitCreator = profitCreator;
        }
        public abstract void CreateProfit();
    }
}

JuniorProgrammer

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DesignPattern.Bridge.BLL {
    class JuniorProgrammer : Programmer {
        public JuniorProgrammer(string name) 
            : base(name) { 
        
        }

        public override void CreateProfit() {
            this.profitCreator.CreateProfit();
        }
    }
}

SeniorProgrammer

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DesignPattern.Bridge.BLL {
    class SeniorProgrammer : Programmer {

        public SeniorProgrammer(string name)
            : base(name) { 
        
        }
        public override void CreateProfit() {
            this.profitCreator.CreateProfit();
        }
    }
}

IProfitCreator

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DesignPattern.Bridge.BLL {
    interface IProfitCreator {
        void CreateProfit();
    }
}

LowProfitCreator

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DesignPattern.Bridge.BLL {
    class LowProfitCreator : IProfitCreator {
        IProfitCreator Members#region IProfitCreator Members

        public void CreateProfit() {
            Console.WriteLine("I create $200000 a year!");
        }

        #endregion
    }
}

HighProfitCreator

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DesignPattern.Bridge.BLL {
    class HighProfitCreator : IProfitCreator {
        IProfitCreator Members#region IProfitCreator Members

        public void CreateProfit() {
            Console.WriteLine("I create $900000 a year!");
        }

        #endregion
    }
}

Client

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using DesignPattern.Bridge.BLL;

namespace DesignPattern.Bridge {
    class Program {
        static void Main(string[] args) {

            Programmer junior = new JuniorProgrammer("bruce Lee");
            junior.SetProfitCreator(new LowProfitCreator());
            junior.CreateProfit();

            Programmer senior = new SeniorProgrammer("guozhijian");
            senior.SetProfitCreator(new HighProfitCreator());
            senior.CreateProfit();
        }
    }
}

Output