设计模式中介者模式(MediatorPattern)

核心模块：抽象中介者、具体中介者、抽象同事类、具体同事类

所有代码请访问：git@code.aliyun.com:289804201/PatternLearn.git

使用场景：双方不直接交流的情况下，进行通信(调用等)；

优点：降低耦合性，不需要显示的调用对象，减少系统对象之间的耦合；

缺点：关系过于复杂的话，中介类将异常庞大；

注意：
1，不同于访问者模式，访问者模式有具体的数据元，且访问模式数据元可扩展；

/**
* Created by tory on 2017/12/11.
* //中介者模式，
* 适合两人之间单独联系；不适合群聊
* 不同与访问者模式，访问者模式有固定的数据元或者流程，
* 优点，解耦，减少子类：缺点，中介者过于庞大
*/
public class MediatorPattern {
public static void main(String[] args) {
HouseMediator mediator = new HouseMediator();
TenantPerson tenant = new TenantPerson("tory",mediator);
HousePerson owner = new HousePerson("jay",mediator);
mediator.setHouseowner(owner);
mediator.setTenant(tenant);

tenant.contact("hello");
owner.contact("do you need house?");
tenant.contact("yes,i do!!");

}
}

//Meditor 抽象中介者
abstract class Mediator {
abstract void contact(String message, Person person);
}

//ConcreteMediator 具体中介者
class HouseMediator extends Mediator {
//中介者要知道通信的双方，如果关系过大，比如群聊，或者散发性网络，中介者将异常庞大
TenantPerson tenant;
HousePerson houseowner;

public void setTenant(TenantPerson tenant) {
this.tenant = tenant;
}

public void setHouseowner(HousePerson houseowner) {
this.houseowner = houseowner;
}

@Override
void contact(String message, Person person) {
//这里实现opc,
//person 发送者Person 发送的message
if (person == tenant) {
houseowner.getMessage(message);
} else if (houseowner == person) {
tenant.getMessage(message);
}
}
//房屋中介

}

//Colleague 抽象同事类
abstract class Person {
String name;
Mediator mediator;

Person(String name, Mediator mediator) {
this.name = name;
this.mediator = mediator;
}
}

//ConcreteColleague 具体同事类
class TenantPerson extends Person {
//承租人
TenantPerson(String name, Mediator mediator) {
super(name, mediator);
}

void contact(String message) {
mediator.contact(message, this);
}

void getMessage(String message) {
System.out.println("Tenant," + name + " receive:" + message);
}
}

class HousePerson extends Person {
//房东
HousePerson(String name, Mediator mediator) {
super(name, mediator);
}

void contact(String message) {
mediator.contact(message, this);
}

void getMessage(String message) {
System.out.println("HouseOwner," + name + " receive:" + message);
}
}

内容打印
Hello World!
HouseOwner,jay receive:hello
Tenant,tory receive:do you need house?
HouseOwner,jay receive:yes,i do!!