中介者模式
一. 中介者模式
1.1 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的相互作用,从而使耦合松散,而且可以独立的改变他们之间的交互.
1.2 角色
- 抽象中介者类(AbstractMediator).
- 具体中介者实现类(Mediator).
- 同事类(Colleague).
二. 具体实现
2.1 创建抽象中介者对象
public abstract class AbstractMediator {
private ColleagueA colleagueA;
private ColleagueB colleagueB;
public abstract void executeToA();
public abstract void executeToB();
public void setColleagueA(ColleagueA colleagueA) {
this.colleagueA = colleagueA;
}
public void setColleagueB(ColleagueB colleagueB) {
this.colleagueB = colleagueB;
}
}
2.2 创建具体中介者对象
public class Mediator extends AbstractMediator {
public void executeToA() {
System.out.println("Mediator executeToA ...");
}
public void executeToB() {
System.out.println("Mediator executeToB ...");
}
}
2.3 创建同事类
public class ColleagueA {
private AbstractMediator mediator;
public ColleagueA(AbstractMediator mediator){
this.mediator = mediator;
}
public void print(){
System.out.println("ColleagueA print ... ");
mediator.executeToB();
}
}
public class ColleagueB {
private AbstractMediator mediator;
public ColleagueB(AbstractMediator mediator){
this.mediator = mediator;
}
public void print(){
System.out.println("ColleagueB print ...");
mediator.executeToA();
}
}
2.4 调用
public static void main(String[] args) {
AbstractMediator mediator = new Mediator();
ColleagueA colleagueA = new ColleagueA(mediator);
ColleagueB colleagueB = new ColleagueB(mediator);
mediator.setColleagueA(colleagueA);
mediator.setColleagueB(colleagueB);
colleagueA.print();
colleagueB.print();
}
2.5 输出
ColleagueA print ...
Mediator executeToB ...
ColleagueB print ...
Mediator executeToA ...
三. 优缺点
3.1 优点
- 各个同事类之间的解耦.
- 降低类的复杂度.
3.2 缺点
- 同事类过多会使中介者庞大,难以维护.
四. 源码
https://github.com/Seasons20/DisignPattern.git
END
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