对象行为型

介绍

顾名思义就是从对象和对象直接交接转（对象-对象）变成（对象-中介者-对象）

定义

用一个中介者对象封装一系列的对象交互，中介者使各对象不需要显示地相互作用，从而使耦合松散，而且可以独立地改变它们之间的交互

使用场景

对象与对象之间关系复杂呈现网状结构时，通过中介者可以适量降低对象与对象之间关系的复杂程度（耦合）

入门案例：

UML图解：

代码：

Children:

public abstract class Children {
    //心情
    protected Mood mood;
    //说话
    protected String say;
    //角色
    protected String role;

    /**
     * @param role 角色
     * @param mood 心情
     * @param say 说话
     */
    protected Children(String role, Mood mood, String say) {
        this.role = role;
        this.mood = mood;
        this.say = say;
    }

    //没用中间人调解时使用的调解方法
    public void mediate(String msg, Children children) {

        if("对不起".equals(msg)){
            children.setMood(Mood.HAPPY);
            this.setMood(Mood.HAPPY);
            this.setSay("没关系，我这个做" + this.getRole() + "的也有不对");
        }else if ("不道歉".equals(msg)){
            children.setMood(Mood.SAD);
            this.setMood(Mood.SAD);
            this.setSay("哼，就是" + this.getRole() + "不对");
        }else{
            throw new RuntimeException("要不道歉要不滚蛋");
        }
    }


    //显示心情和说话
    public void showMood() {
        System.out.println("现在心情::" + this.getMood().getMsg() );
        System.out.println( this.getSay() );
    }

    public Mood getMood() {
        return mood;
    }

    public void setMood(Mood mood) {
        this.mood = mood;
    }

    public String getSay() {
        return say;
    }

    public void setSay(String say) {
        this.say = say;
    }

    public String getRole() {
        return role;
    }

    public void setRole(String role) {
        this.role = role;
    }
}

XiaoMing:

public class XiaoMing extends Children {

    public XiaoMing(String role, Mood mood, String say) {
        super(role, mood, say);
    }

}

XiaoHong:

public class XiaoHong extends Children {

    public XiaoHong(String role, Mood mood, String say) {
        super(role, mood, say);
    }

}

Mediator:

//中间人
public abstract class Mediator {

    protected Children children1;
    protected Children children2;

    protected Mediator(Children children1, Children children2){
        this.children1 = children1;
        this.children2 = children2;
    }

    /**
     * 中间人调解方法
     * @param say 道歉方说话 说话标准参考枚举 SAY
     * @param children1 道歉方
     * @param children2 接受方
     */
    public abstract void mediate(String say, Children children1, Children children2);

    //setter和getter
    public Children getChildren1() {
        return children1;
    }

    public void setChildren1(Children children1) {
        this.children1 = children1;
    }

    public Children getChildren2() {
        return children2;
    }

    public void setChildren2(Children children2) {
        this.children2 = children2;
    }
}

Mother:

//ConcreteMediator
public class Mother extends Mediator {
    public Mother(Children children1, Children children2) {
        super(children1, children2);
    }

    @Override
    public void mediate(String say, Children children1, Children children2) {

        switch (say){
            case "对不起":
                children2.mediate(say, children1);
                break;

            case "不道歉":
                children2.mediate(say, children1);
                break;

            default:
                throw new RuntimeException("要不道歉要不滚蛋");
        }

    }
}

过程用到的枚举：

//心情
public enum Mood {
    SAD("难过"), //伤心
    HAPPY("高兴") //高兴
    ;

    private String msg;

    Mood(String msg) {
        this.msg = msg;
    }

    public String getMsg() {
        return msg;
    }
}


//话语
public enum Say {
    SORRY("对不起"), //伤心
    NOWAY("不道歉") //高兴
    ;

    private String msg;

    Say(String msg) {
        this.msg = msg;
    }

    public String getMsg() {
        return msg;
    }
}

Client(测试):

public class Main {
    public static void main(String[] args){

        /**
         * 情景：小明和小红是两姐弟，今天为了雪糕闹翻了
         */
        XiaoMing xiaoMing = new XiaoMing( "弟弟", Mood.SAD, "她吃了我的雪糕" );
        XiaoHong xiaoHong = new XiaoHong( "姐姐", Mood.SAD, "这是我的雪糕" );

        System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxxxx 【调解关系之前】 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");

        //调解之前
        xiaoMing.showMood();
        System.out.println("----------------------------");
        xiaoHong.showMood();


        System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxxxx 【双方自我调解】 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
        //解决方案1：直接调解关系，小明认错
        xiaoMing.setSay(Say.SORRY.getMsg());
        xiaoHong.mediate(xiaoMing.getSay(), xiaoMing);

        xiaoMing.showMood();
        System.out.println("----------------------------");
        xiaoHong.showMood();

        System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxxxx 【通过妈妈做中间人调解】 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");

        //解决方案2：通过妈妈来调解，小明认错，但不好意思和姐姐说
//        xiaoMing.setSay( Say.NOWAY.getMsg() );
        xiaoMing.setSay( Say.SORRY.getMsg() );
        Mother mother = new Mother(xiaoMing, xiaoHong);
        mother.mediate(xiaoMing.getSay(), xiaoMing, xiaoHong);

        xiaoMing.showMood();
        System.out.println("----------------------------");
        xiaoHong.showMood();

        /**
         * output:
             xxxxxxxxxxxxxxxxxxxxxxxxxxx 【调解关系之前】 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
             现在心情::难过
             她吃了我的雪糕
             ----------------------------
             现在心情::难过
             这是我的雪糕
             xxxxxxxxxxxxxxxxxxxxxxxxxxx 【双方自我调解】 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
             现在心情::高兴
             对不起
             ----------------------------
             现在心情::高兴
             没关系，我这个做姐姐的也有不对
             xxxxxxxxxxxxxxxxxxxxxxxxxxx 【通过妈妈做中间人调解】 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
             现在心情::高兴
             对不起
             ----------------------------
             现在心情::高兴
             没关系，我这个做姐姐的也有不对
         */

    }
}