乐在其中设计模式(C#) - 中介者模式(Mediator Pattern).doc

介绍用一个中介对象来封装一系列的对象交互。中介者使各对象不需要显式地相互引用，从而使其耦合松散，而且可以独立地改变它们之间的交互。示例有一个Message实体类，某个对象对它的操作有Send()和Insert()方法，现在用一个中介对象来封装这一系列的对象交互。MessageModelusingSystem;usingSystem.Collections.Generic;usingSystem.Text; namespacePattern.Mediator/*/Message实体类/publicclassMessageModel/*/构造函数/Message内容/Message发布时间publicMessageModel(stringmsg,DateTimept)this._message=msg;this._publishTime=pt;privatestring_message;/*/Message内容/publicstringMessagegetreturn_message;set_message=value;privateDateTime_publishTime;/*/Message发布时间/publicDateTimePublishTimegetreturn_publishTime;set_publishTime=value;AbstractMessageMediatorusingSystem;usingSystem.Collections.Generic;usingSystem.Text; namespacePattern.Mediator/*/抽象中介者（Mediator）/publicabstractclassAbstractMessageMediator/*/注册一个操作Message的对象/AbstractMessagepublicabstractvoidRegister(AbstractMessageAbstractMessage);/*/发送Message/来自UserId/发送到UserId/Message实体对象/publicabstractstringSend(stringfrom,stringto,MessageModelmm);MessageMediatorusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Mediator/*/中介者（ConcreteMediator）/publicclassMessageMediator:AbstractMessageMediatorprivateDictionary_dictionary=newDictionary();/*/注册一个操作Message的对象/AbstractMessagepublicoverridevoidRegister(AbstractMessageabstractMessage)if(!_dictionary.ContainsKey(abstractMessage.UserId)_dictionary.Add(abstractMessage.UserId,abstractMessage);abstractMessage.AbstractMessageMediator=this;/*/发送Message/来自UserId/发送到UserId/Message实体对象/publicoverridestringSend(stringfrom,stringto,MessageModelmm)AbstractMessageabstractMessage=_dictionaryto;if(abstractMessage!=null)returnabstractMessage.Insert(from,mm);elsereturnnull;AbstractMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Mediator/*/操作Message抽象类（Colleague）/publicabstractclassAbstractMessageprivateAbstractMessageMediator_abstractMessageMediator;privatestring_userId;/*/构造函数/UserIdpublicAbstractMessage(stringuserId)this._userId=userId;/*/UserId/publicstringUserIdgetreturn_userId;/*/中介者/publicAbstractMessageMediatorAbstractMessageMediatorgetreturn_abstractMessageMediator;set_abstractMessageMediator=value;/*/发送Message（由客户端调用）/发送到UserId/Message实体对象/publicstringSend(stringto,MessageModelmm)return_abstractMessageMediator.Send(_userId,to,mm);/*/接受Message（由中介者调用）/来自UserId/Message实体对象/publicabstractstringInsert(stringfrom,MessageModelmm);SqlMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Mediator/*/Sql方式操作Message（ConcreteColleague）/publicclassSqlMessage:AbstractMessage/*/构造函数/UserIdpublicSqlMessage(stringuserId):base(userId)/*/接受Message（由中介者调用）/来自UserId/Message实体对象/publicoverridestringInsert(stringfrom,MessageModelmm)returnSql方式插入Message（+from+发送给+base.UserId+）+-内容：+mm.Message+-时间：+mm.PublishTime.ToString();XmlMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Mediator/*/Xml方式操作Message（ConcreteColleague）/publicclassXmlMessage:AbstractMessage/*/构造函数/UserIdpublicXmlMessage(stringuserId):base(userId)/*/接受Message（由中介者调用）/来自UserId/Message实体对象/publicoverridestringInsert(stringfrom,MessageModelmm)returnXml方式插入Message（+from+发送给+base.UserId+）+-内容：+mm.Message+-时间：+mm.PublishTime.ToString();TestusingSystem;usingSystem.Data;usingSystem.Configuration;usingSystem.Collections;usingSystem.Web;usingSystem.Web.Security;usingSystem.Web.UI;usingSystem.Web.UI.WebControls;usingSystem.Web.UI.WebControls.WebParts;usingSystem.Web.UI.HtmlControls;usingPattern.Mediator;publicpartialclassMediator:System.Web.UI.PageprotectedvoidPage_Load(objectsender,EventArgse)AbstractMessageMediatormessageMediator=newMessageMediator();AbstractMessageuser1=newSqlMessage(user1);AbstractMessageuser2=newSqlMessage(user2);AbstractMessageuser3=newXmlMessage(user3);AbstractMessageuser4=newXmlMessage(user4);messageMediator.Register(user1);messageMediator.Register(user2);messageMediator.Register(user3);messageMediator.Register(user4);Response.Write(user1.Send(user2,newMessageModel(你好！,DateTime.Now);Response.Write();Response.Write(user2.Send(user1,newMessageModel(我不好！,DateTime.Now);Response.Write();Response.Write(user1.Send(user2,newMessageModel(不好就不好吧。,DateTime.Now);Response.Write();Response.Write(user3.Send(user4,newMessageModel(吃了吗？,DateTime.Now);Response.Write();Response.Write(user4.Send(user3,newMessageModel(没吃，你请我？,DateTime.Now);Response.Write();Response.Write(user3.Send(user4,newMessageModel(不请。,DateTime.Now);Response.Write();运行结果Sql方式插入Message（user1发送给user2） - 内容：你好！ - 时间：2007-5-19 23:43:19Sql方式插入Message（user2发送给user1） - 内容：我不好！ - 时间：2007-5-19 23:43:19Sql方式插入Message（u