《大话设计模式》java实现之中介者模式

中介者模式个人理解为中介者持有其他关联对象的引用，把原先各对象之间的复杂关系集合在中介者中去
UML

代码结构

public class Client {    public static void main(String[] args) {        UnitedNationsSecurityCouncil unsc = new UnitedNationsSecurityCouncil();        USA c1 = new USA(unsc);        Iraq c2 = new Iraq(unsc);        unsc.setColleague1(c1);        unsc.setColleague2(c2);        c1.declare("不准研制核武器，否则要发动战争！");        c2.declare("我们没有核武器，也不怕侵略");    }}

public abstract class Country {    protected UnitedNations mediator;    public Country(UnitedNations mediator) {        super();        this.mediator = mediator;    }}

public class Iraq extends Country {    public Iraq(UnitedNations mediator) {        super(mediator);    }    //声明    public void declare(String message) {        mediator.declare(message, this);    }    //获得消息    public void getMessage(String message) {        System.out.println("伊拉克获得对方消息：" + message);    }}

public abstract class UnitedNations {    public abstract void declare(String message, Country colleague);}

public class UnitedNationsSecurityCouncil extends UnitedNations {    private USA colleague1;    private Iraq colleague2;    public USA getColleague1() {        return colleague1;    }    public void setColleague1(USA colleague1) {        this.colleague1 = colleague1;    }    public Iraq getColleague2() {        return colleague2;    }    public void setColleague2(Iraq colleague2) {        this.colleague2 = colleague2;    }    @Override    public void declare(String message, Country colleague) {        if(colleague == colleague1) {            colleague2.getMessage(message);        } else {            colleague1.getMessage(message);        }    }}

public class USA extends Country {    public USA(UnitedNations mediator) {        super(mediator);    }    //声明    public void declare(String message) {        mediator.declare(message, this);    }    //获得消息    public void getMessage(String message) {        System.out.println("美国获得对方消息：" + message);    }}

运行结果