研磨设计模式文摘

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创建型 5

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1. Builder ------- 分离整体构建算法和部件构造

具体问题：数据导出格式（头，体，尾）

一般问题：同一个构建过程有着不同的表示

客户端:

2. Prototype ------- 克隆生成对象

具体问题：订单处理系统

一般问题：一个系统想要独立于它想要使用的对象

客户端:

Prototype newPrototype = prototype.clone();

3. Singleton -------- 控制实例数目

具体问题：读取配置文件的内容

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4. 简单工厂 -------- 选择实现

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5. Factory Method -------- 延迟到子类选择实现

6. Abstract Factory -------- 选择产品簇的实现

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结构型 7

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1.Decorator ------- 动态组合

具体问题：复杂的奖金计算

一般问题：不影响其他对象的情况下，以动态，透明的方式给对象添加职责;

    public abstract class Component    {        public abstract double calcPrice(string user, DateTime begin, DateTime end);    }    public class ConcreteComponent : Component    {        public override double calcPrice(string user, DateTime begin, DateTime end)        {            return 0;        }    }    public abstract class Decorator : Component    {        protected Component _c;        public Decorator(Component c)        {            this._c = c;        }        public override double calcPrice(string user, DateTime begin, DateTime end)        {            return this._c.calcPrice(user, begin, end);        }    }    public class MonthPrizeDecorator : Decorator    {        public MonthPrizeDecorator(Component c) : base(c) { }        public override double calcPrice(string user, DateTime begin, DateTime end)        {            double money  = base.calcPrice(user, begin, end);            return money + 100;        }    }    public class SumPrizeDecorator : Decorator    {        public SumPrizeDecorator(Component c) : base(c) { }        public override double calcPrice(string user, DateTime begin, DateTime end)        {            double money = base.calcPrice(user, begin, end);            return money + 1000;        }    }    public class GroupPrizeDecorator : Decorator    {        public GroupPrizeDecorator(Component c) : base(c) { }        public override double calcPrice(string user, DateTime begin, DateTime end)        {            double money = base.calcPrice(user, begin, end);            return money + 10000;        }    }

客户端:

  Component c1 = new ConcreteComponent();            Decorator d1 = new MonthPrizeDecorator(c1);            d1.calcPrice("aa", DateTime.Now, DateTime.Now);            Decorator d2 = new SumPrizeDecorator(d1);            d2.calcPrice("bb", DateTime.Now, DateTime.Now);            Decorator d3 = new GroupPrizeDecorator(d2);            d3.calcPrice("cc", DateTime.Now, DateTime.Now);

2.Composite ------- 统一叶子对象和组合对象

具体问题：商品类别树；

一般问题：部分整体层次结构；统一地使用组合结构中的所有对象;

客户端:

Component root = new Composite(“服装”);

Component c1 = new Composite(“男装”);

Component c2 = new Composite(“女装”);

Component leaf1 = new Leaf(“衬衣”);

Component leaf2 = new Leaf(“夹克”);

Component leaf3 = new Leaf(“裙子”);

Component leaf4 = new Leaf(“套装”);

root.addChild(c1);

root.addChild(c2);

c1. addChild(leaf1);

c1. addChild(leaf2);

c2. addChild(leaf3);

c2. addChild(leaf4);

3.Adapter ------- 转换匹配，复用功能

具体问题：同时支持数据库和文件的日志管理

一般问题：转换接口；复用类；

客户端:

Adaptee adaptee = new Adaptee ();

Target target = new Adapter(adaptee);

target.request();

4.Facade ------- 封装交互简化调用

具体问题：代码生成三层模块

一般问题：复杂的子系统提供一个简单的接口；客户程序和抽象类的实现部分松散耦合；

构建多层结构的系统;

Class Façade

{

Public void test()

{

AModultApi a = new AModuleImpl();

a.testA();

BModultApi b = new BModuleImpl();

b.testB();

}

客户端：

new Façade().test();

5.Flyweight ------- 分离与共享

具体问题：权限中读取缓存中的数据

一般问题:如果一个应用程序使用了大量的细粒度对象

6.Proxy ------- 控制对象访问

具体问题：读取大量数据问题

一般问题 :（1）虚代理：需要创建开销很大的对象; (2)保护代理：控制对原始对象的访问，判断权限；（3）远程代理：为一个对象在不同的地址空间提供局部代表；（4）智引代理：在访问对象执行一些附加操作;

7.Bridge ------- 分离抽象和实现

具体问题：发送消息（内部，邮件，手机）(普通，加急，特急)

一般问题：抽象部分和实现部分能够扩展；采用继承的方案，产生很多类;

    public interface MessageImplementor    {        void send(string message, string toUser);    }    public interface AbstractMessage    {        void sendMessage(string message, string toUser);    }    public class MessageSMS : MessageImplementor    {        public void send(string message, string toUser)        {            Console.WriteLine("站内短消息发送" + message + toUser);        }    }    public class MessageEmail : MessageImplementor    {        public void send(string message, string toUser)        {            Console.WriteLine("e-mail发送" + message + toUser);        }    }    public class CommonMessage : AbstractMessage    {        private MessageImplementor _impl;        public CommonMessage(MessageImplementor impl)        {            this._impl = impl;        }        public void sendMessage(string message, string toUser)        {            this._impl.send(message, toUser);        }    }    public class UrgencyMessage : AbstractMessage    {        private MessageImplementor _impl;        public UrgencyMessage(MessageImplementor impl)        {            this._impl = impl;        }        public void sendMessage(string message, string toUser)        {            this._impl.send(message, toUser);        }    }

客户端：

 MessageImplementor impl = new MessageSMS();            AbstractMessage m = new CommonMessage(impl);            m.sendMessage("aa","bb");            impl = new MessageEmail();            m = new CommonMessage(impl);            m.sendMessage("cc","dd");

行为型 11

1. Strategy ------- 分离算法，选择实现

具体问题：向客户包报价

一般问题：封装算法；同一个算法，不同实现；if /else语句

客户端:

Strategy strategy = new ConcreteStrategyA();

Context context = new Context(strategy);

context.contextInterface();

2. State ------- 根据状态来分离和选择行为

具体问题：在线分类投票

一般问题：一个对象的行为取决于状态;依赖于状态的多分支结构;

3. Command ------- 封装请求

具体问题：开机模式

一般问题：不同的时刻指定，排列，执行请求; undo;

客户端:

Receicer receiver = new Receiver();

Command command = new ConcreteCommand(receiver);

Invoker invoker = new Invoker();

invoker.setCommand(command);

invoker.runCommand();

4. Observer ------- 触发联动

具体问题：订阅报纸；

一般问题：操作依赖于状态的变化；更改一个对象，连同更改其他对象；

客户端:

ConcreteSubject subject = new ConcreteSubject ();

ConcreteObserver a1 = new ConcreteObserver ();

a1.setName(“张三”);

ConcreteObserver a2= new ConcreteObserver ();

a2.setName(“李四”);

ConcreteObserver a3 = new ConcreteObserver ();

a3.setName(“王五”);

subject.attach(a1);

subject.attach(a2);

subject.attach(a3);

subject.setContent();

5. Mediator -------- 封装交互

具体问题：主板上各个配件交互

一般问题：一组对象之间的通信；

客户端:

ConcreteMediator mediator = new ConcreteMediator();

ConcreteColleagueA a = new ConcreteColleagueA (mediator) ;

mediator..setConcreteColleagueA(a);

a.someOperation();

6. Chain of Responsibility-------- 分离职责 ,动态组合

具体问题：申请聚餐费用项目经理——》部门经理——》总经理

一般问题：如果多个对象可以处理同一个请求，具体哪个对象处理请求，是运行动态确定

   public abstract class Handler    {        protected Handler _successor = null;        public void setSuccessor(Handler successor)        {            this._successor = successor;        }        public abstract string handleFeeRequest(string user, double fee);    }    public class ProjectManager : Handler    {        public override string handleFeeRequest(string user, double fee)        {            string str = string.Empty;            if (fee < 500)            {                str = "项目经理处理!";            }            else            {                if (this._successor != null)                {                    return _successor.handleFeeRequest(user, fee);                }            }            return str;        }    }    public class DepManager : Handler    {        public override string handleFeeRequest(string user, double fee)        {            string str = string.Empty;            if (fee < 1000)            {                str = "部门经理处理!";            }            else            {                if (this._successor != null)                {                    return _successor.handleFeeRequest(user, fee);                }            }            return str;        }    }    public class GeneralManager : Handler    {        public override string handleFeeRequest(string user, double fee)        {            string str = string.Empty;            if (fee >= 1000)            {                str = "总经理处理!";            }            else            {                if (this._successor != null)                {                    return _successor.handleFeeRequest(user, fee);                }            }            return str;        }    }

客户端:

  Handler h1 = new GeneralManager();            Handler h2 = new DepManager();            Handler h3 = new ProjectManager();            h3.setSuccessor(h2);            h2.setSuccessor(h1);            Console.WriteLine(h3.handleFeeRequest("aa", 400));            Console.WriteLine(h3.handleFeeRequest("aa", 600));            Console.WriteLine(h3.handleFeeRequest("aa", 1400));

输出:

项目经理处理!
部门经理处理!
总经理处理!

7. Visitor ----- 预留回路，回调实现

具体问题：客户管理增加偏好分析和价值分析

一般问题：给对象结构中的元素对象定义新的操作;

模式使用前:

    public abstract class Customer    {        public string customerId { get; set; }        public string name { get; set; }        public abstract void serviceRequest();        public abstract void predilectionAnalyze();        public abstract void worthAnalyze();    }    public class EnterpriseCustomer : Customer    {        public string linkman { get; set; }        public string linkTelephone { get; set; }        public string registerAddress { get; set; }        public override void serviceRequest()        {            Console.WriteLine(this.name + "企业提出服务请求!");        }        public override void predilectionAnalyze()        {            Console.WriteLine(this.name + "企业偏好分析!");        }        public override void worthAnalyze()        {            Console.WriteLine(this.name + "企业价值分析!");        }    }    public class PersonalCustomer : Customer    {        public string telephone { set; get; }        public int age { set; get; }        public string registerAddress { get; set; }        public override void serviceRequest()        {            Console.WriteLine(this.name + "客户提出服务请求!");        }        public override void predilectionAnalyze()        {            Console.WriteLine(this.name + "各户偏好分析!");        }        public override void worthAnalyze()        {            Console.WriteLine(this.name + "各户价值分析!");        }    }

     static void Main()        {            List<Customer> cols = testData();            foreach(Customer col in cols)            {                col.predilectionAnalyze();                col.worthAnalyze();            }        }        static List<Customer> testData()        {            List<Customer> col = new List<Customer>();            Customer cm1 = new EnterpriseCustomer();            cm1.name = "a";            col.Add(cm1);            Customer cm2 = new EnterpriseCustomer();            cm2.name = "b";            col.Add(cm2);            Customer cm3 = new PersonalCustomer();            cm3.name = "b";            col.Add(cm3);            return col;        }

输出:

a企业偏好分析!
a企业价值分析!
b企业偏好分析!
b企业价值分析!
b各户偏好分析!
b各户价值分析!

模式使用后:

    public abstract class Customer    {        public string customerId { get; set; }        public string name { get; set; }        public abstract void accept(Visitor visitor);        //public abstract void serviceRequest();        //public abstract void predilectionAnalyze();        //public abstract void worthAnalyze();    }    public class EnterpriseCustomer : Customer    {        public string linkman { get; set; }        public string linkTelephone { get; set; }        public string registerAddress { get; set; }        //public override void serviceRequest()        //{        //    Console.WriteLine(this.name + "企业提出服务请求!");        //}        //public override void predilectionAnalyze()        //{        //    Console.WriteLine(this.name + "企业偏好分析!");        //}        //public override void worthAnalyze()        //{        //    Console.WriteLine(this.name + "企业价值分析!");        //}        public override void accept(Visitor visitor)        {            visitor.visitEnteroriseCustomer(this);        }    }    public class PersonalCustomer : Customer    {        public string telephone { set; get; }        public int age { set; get; }        public string registerAddress { get; set; }        //public override void serviceRequest()        //{        //    Console.WriteLine(this.name + "客户提出服务请求!");        //}        //public override void predilectionAnalyze()        //{        //    Console.WriteLine(this.name + "各户偏好分析!");        //}        //public override void worthAnalyze()        //{        //    Console.WriteLine(this.name + "各户价值分析!");        //}        public override void accept(Visitor visitor)        {            visitor.visitPersonalCustomer(this);        }    }    public interface Visitor    {        void visitEnteroriseCustomer(EnterpriseCustomer ec);        void visitPersonalCustomer(PersonalCustomer pc);    }    public class ServiceRequestVisitor : Visitor    {        public void visitEnteroriseCustomer(EnterpriseCustomer ec)        {            Console.WriteLine(ec.name + "企业提出服务请求!");        }        public void visitPersonalCustomer(PersonalCustomer pc)        {            Console.WriteLine(pc.name + "客户提出服务请求!");        }    }    public class PredilectionAnalyzwVisitor : Visitor    {        public void visitEnteroriseCustomer(EnterpriseCustomer ec)        {            Console.WriteLine(ec.name + "企业偏好分析!");        }        public void visitPersonalCustomer(PersonalCustomer pc)        {            Console.WriteLine(pc.name + "各户偏好分析!");        }    }    public class WorthAnalyzwVisitor : Visitor    {        public void visitEnteroriseCustomer(EnterpriseCustomer ec)        {            Console.WriteLine(ec.name + "企业价值分析!");        }        public void visitPersonalCustomer(PersonalCustomer pc)        {            Console.WriteLine(pc.name + "各户价值分析!");        }    }    public class ObjectStructure    {        private List<Customer> col = new List<Customer>();        public void handleRequest(Visitor visitor)        {            foreach(Customer cm in col)            {                cm.accept(visitor);            }        }        public void addElement(Customer el)        {            this.col.Add(el);        }    }

   ObjectStructure os = new ObjectStructure();            Customer cm1 = new EnterpriseCustomer();            cm1.name = "a";            os.addElement(cm1);            Customer cm2 = new EnterpriseCustomer();            cm2.name = "b";            os.addElement(cm2);            Customer cm3 = new PersonalCustomer();            cm3.name = "b";            os.addElement(cm3);            ServiceRequestVisitor srVisitor = new ServiceRequestVisitor();            os.handleRequest(srVisitor);            PredilectionAnalyzwVisitor paVisitor = new PredilectionAnalyzwVisitor();            os.handleRequest(paVisitor);            WorthAnalyzwVisitor waVisitor = new WorthAnalyzwVisitor();            os.handleRequest(waVisitor);

输出:

a企业提出服务请求!
b企业提出服务请求!
b客户提出服务请求!
a企业偏好分析!
b企业偏好分析!
b各户偏好分析!
a企业价值分析!
b企业价值分析!
b各户价值分析!

8. Interpreter ----- 分离实现,解释执行

具体问题：读取配置文件

一般问题：当一个语言需要解释执行，语言中的句子表示为一个抽象语法树

9. Memento -------- 保护和恢复内部状态

具体问题：开发访真系统

一般问题：保存一个对象在某一个时刻的全部或者部分状态;

客户端:

Originator ori = new Originator(“test”);

ori.runPhaseOne();

Caretaker care = new Caretaker ();

Memento memento = ori.createMemento();

care saveMemento(memento);

ori. schemal1();

ori.setMemento(care.retireMemento());

ori.schemal2();

10. Template Method -------- 固定算法骨架

11. Iterator -------- 控制访问聚合对象中的元素

具体问题：访问List /数组的数据

一般问题：访问聚合对象

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