定义:用一个中介对象来封装一系列的对象交互。中介者使各对象不需要显式地相互引用,从而使其耦合松散,而且可以独立地改变它们之间的互
结构图:
示例代码:
public abstract class Mediator {
public abstract void send(String message, Colleague colleague);
}
public class ConcreteMediator extends Mediator {
ConcreteColleague1 colleague1;
ConcreteColleague2 colleague2;
public ConcreteColleague1 getColleague1() {
return colleague1;
}
public void setColleague1(ConcreteColleague1 colleague1) {
this.colleague1 = colleague1;
}
public ConcreteColleague2 getColleague2() {
return colleague2;
}
public void setColleague2(ConcreteColleague2 colleague2) {
this.colleague2 = colleague2;
}
@Override
public void send(String message, Colleague colleague) {
// TODO Auto-generated method stub
if (colleague == colleague1) {
colleague2.notify(message);
} else {
colleague1.notify(message);
}
}
}
public abstract class Colleague {
protected Mediator mediator;
public Colleague(Mediator mediator) {
this.mediator = mediator;
}
}
public class ConcreteColleague1 extends Colleague {
public ConcreteColleague1(Mediator mediator) {
super(mediator);
// TODO Auto-generated constructor stub
}
public void send(String message) {
mediator.send(message, this);
}
public void notify(String message) {
System.out.println("同事1得到消息:" + message);
}
}
public class ConcreteColleague2 extends Colleague {
public ConcreteColleague2(Mediator mediator) {
super(mediator);
// TODO Auto-generated constructor stub
}
public void send(String message) {
mediator.send(message, this);
}
public void notify(String message) {
System.out.println("同事2得到消息:" + message);
}
}
客户端代码如下:
public class Client {
public static void main(String[] args) {
ConcreteMediator m = new ConcreteMediator();
ConcreteColleague1 c1 = new ConcreteColleague1(m);
ConcreteColleague2 c2 = new ConcreteColleague2(m);
m.colleague1 = c1;
m.colleague2 = c2;
c1.send("吃饭没?");
c2.send("没有呢,你打算请客?");
}
}
输出结果:
同事2得到消息:吃饭没?
同事1得到消息:没有呢,你打算请客?