制作演示网站,竭诚网络网站建设价格,可以做头像的网站有哪些,如何策划网站一、介绍#xff1a;
1、定义#xff1a;中介者模式#xff08;Mediator Pattern#xff09;是一种行为型设计模式#xff0c;它通过引入一个中介者对象来降低多个对象之间的耦合度。在中介者模式中#xff0c;各个对象之间不直接进行通信#xff0c;而是通过中介者对象…一、介绍
1、定义中介者模式Mediator Pattern是一种行为型设计模式它通过引入一个中介者对象来降低多个对象之间的耦合度。在中介者模式中各个对象之间不直接进行通信而是通过中介者对象进行协调和通信。
2、组成结构 1抽象中介者Abstract Mediator定义了中介者对象的接口用于协调各个同事对象之间的交互。
2具体中介者Concrete Mediator实现了抽象中介者接口负责协调各个同事对象的交互并了解各个同事对象的具体实现。
3抽象同事类Abstract Colleague定义了同事对象的接口通常持有一个中介者对象的引用用于与中介者进行通信。
4具体同事类Concrete Colleague实现了抽象同事类的接口实现自身的业务逻辑并通过中介者对象进行与其他同事对象的通信。
// 抽象中介者
interface Mediator {void send(String message, Colleague colleague);
}// 具体中介者
class ConcreteMediator implements Mediator {private Colleague colleague1;private Colleague colleague2;public void setColleague1(Colleague colleague1) {this.colleague1 colleague1;}public void setColleague2(Colleague colleague2) {this.colleague2 colleague2;}Overridepublic void send(String message, Colleague colleague) {if (colleague colleague1) {colleague2.receive(message);} else {colleague1.receive(message);}}
}// 抽象同事类
abstract class Colleague {protected Mediator mediator;public Colleague(Mediator mediator) {this.mediator mediator;}public abstract void send(String message);public abstract void receive(String message);
}// 具体同事类
class ConcreteColleague1 extends Colleague {public ConcreteColleague1(Mediator mediator) {super(mediator);}Overridepublic void send(String message) {mediator.send(message, this);}Overridepublic void receive(String message) {System.out.println(ConcreteColleague1 Received: message);}
}class ConcreteColleague2 extends Colleague {public ConcreteColleague2(Mediator mediator) {super(mediator);}Overridepublic void send(String message) {mediator.send(message, this);}Overridepublic void receive(String message) {System.out.println(ConcreteColleague2 Received: message);}
}// 客户端
public static void main(String[] args) {ConcreteMediator mediator new ConcreteMediator();ConcreteColleague1 colleague1 new ConcreteColleague1(mediator);ConcreteColleague2 colleague2 new ConcreteColleague2(mediator);mediator.setColleague1(colleague1);mediator.setColleague2(colleague2);colleague1.send(msg from Colleague1);colleague2.send(msg from Colleague2);}
3、优点
1降低耦合度中介者模式将对象之间的交互集中在中介者对象中减少了对象之间的直接依赖和耦合度使系统更加灵活、可扩展和易于维护。
2简化对象间的通信中介者模式通过引入中介者对象将对象间复杂的相互通信转变为对象与中介者之间的简单交互简化了对象间的通信逻辑。
3集中控制逻辑中介者模式将对象间的交互逻辑集中在中介者对象中使得系统的控制逻辑更加清晰明确。通过定义中介者对象来协调对象间的交互可以更方便地修改和扩展系统的行为。
4促进代码重用中介者模式将公共的交互逻辑封装在中介者对象中可以被多个对象共享和复用避免了代码的重复编写提高了代码的可维护性和可复用性。 4、适用场景
1当一个系统中对象之间存在复杂的相互关系导致对象间的交互逻辑难以维护和扩展时可以考虑使用中介者模式来简化交互逻辑。
2当一个对象需要对多个对象进行操作或通知时可以引入中介者模式来集中管理这些对象之间的交互。
3当系统中的对象之间存在循环依赖关系不方便直接进行交互时可以通过引入中介者对象来解决循环依赖问题。
二、demo
1、房租中介三个房东、三个租客。房东类和租客类互相影响称为同事类。
1抽象同事类
import java.util.Objects;/*** 抽象同事类(这里指房东、租客),有用户名称以及消息发送、接收功能*/
public abstract class Colleague {//租客、房东 都认识中介Mediator mediator;public String userName;public Colleague(String userName, Mediator mediator){this.userName userName;this.mediator mediator;}//这里对userName做equals和hashCode是为了后面可以用contains判断方法Overridepublic boolean equals(Object o) {if (this o) return true;if (o null || getClass() ! o.getClass()) return false;Colleague colleague (Colleague) o;return Objects.equals(userName, colleague.userName);}Overridepublic int hashCode() {return Objects.hash(userName);}public void sendMsg(String msg){System.out.println(我this.userName发送消息);}public void receiveMsg(String msg,Colleague fromColleague){}
}2具体同事类房东和租客
//房东类
public class LandlordColleague extends Colleague{public LandlordColleague(String userName, Mediator mediator) {super(userName,mediator);}//发送消息需要通知谁 谁可以收到由中介完成Overridepublic void sendMsg(String msg) {super.sendMsg(msg);mediator.notice(msg,this);}//收到中介发送的消息Overridepublic void receiveMsg(String msg,Colleague fromColleague) {System.out.println(房东this.userName收到fromColleague.userName发送的消息msg);}
}import java.util.List;//租客同事类
public class TenantColleague extends Colleague {public TenantColleague(String userName, Mediator mediator) {super(userName,mediator);}//发送消息谁可以收到所有房东由中介完成Overridepublic void sendMsg(String msg) {super.sendMsg(msg);mediator.notice(msg,this);}//收到消息Overridepublic void receiveMsg(String msg,Colleague fromColleague) {System.out.println(租客this.userName收到fromColleague.userName发送的消息msg);}
}3抽象中介
//抽象中介
public interface Mediator {//通知void notice(String msg,Colleague fromColleague);
}4具体中介
import java.util.ArrayList;
import java.util.List;/*** 房租中介*/
public class RentMediator implements Mediator{//所有租客ListColleague tenantColleagues new ArrayList();//所有房东ListColleague landlordColleagues new ArrayList();//添加房东void addLandlord(Colleague colleague){this.landlordColleagues.add(colleague);}//添加租客void addTenantColleague(Colleague colleague){this.tenantColleagues.add(colleague);}/*** 通知* 通知所有房东or 租客* param msg* param fromColleague*/Overridepublic void notice(String msg, Colleague fromColleague) {//房东发的通知所有租客if(landlordColleagues.contains(fromColleague)){for(Colleague colleague : tenantColleagues){colleague.receiveMsg(msg,fromColleague);}}//租客发的通知所有房东if(tenantColleagues.contains(fromColleague)){for(Colleague colleague : landlordColleagues){colleague.receiveMsg(msg,fromColleague);}}}
}客户端
public class Test {public static void main(String args[]){RentMediator rentMediator new RentMediator();//房东管理LandlordColleague landlordColleague1 new LandlordColleague(房东1,rentMediator);LandlordColleague landlordColleague2 new LandlordColleague(房东2,rentMediator);LandlordColleague landlordColleague3 new LandlordColleague(房东3,rentMediator);rentMediator.addLandlord(landlordColleague1);rentMediator.addLandlord(landlordColleague2);rentMediator.addLandlord(landlordColleague3);//租客管理TenantColleague tenantColleague1 new TenantColleague(租客1,rentMediator);TenantColleague tenantColleague2 new TenantColleague(租客2,rentMediator);TenantColleague tenantColleague3 new TenantColleague(租客3,rentMediator);rentMediator.addTenantColleague(tenantColleague1);rentMediator.addTenantColleague(tenantColleague2);rentMediator.addTenantColleague(tenantColleague3);//tenantColleague2.sendMsg(寻找三室房源);System.out.println(******);landlordColleague3.sendMsg(发布新房源);}
}输出
我租客2发送消息
房东房东1收到租客2发送的消息寻找三室房源
房东房东2收到租客2发送的消息寻找三室房源
房东房东3收到租客2发送的消息寻找三室房源
******
我房东3发送消息
租客租客1收到房东3发送的消息发布新房源
租客租客2收到房东3发送的消息发布新房源
租客租客3收到房东3发送的消息发布新房源
