12种行为模式 之8 MEDIATOR 调停者模式

8、MEDIATOR

调停者模式：

没使用调停者模式 ： 一个过度耦合的系统 ： 网状结构


使用调停者模式 后 ： 以调停者为 中心的星状结构


/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:24:28
* <p/>
* note: 调停者角色
*/
abstract public class Mediator {

/**
* 事件方法
* @param c
*/
public abstract void colleagueChanged(Colleague c);

}

/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:24:39
* <p/>
* note: 具体调停者角色
*/
public class ConcreteMediator extends Mediator {
private Colleague1 colleague1;
private Colleague2 colleague2;

/**
* 将所有同事 实例化
*/
public void createConcreteMediator() {
colleague1 = new Colleague1(this);
colleague2 = new Colleague2(this);
}

/**
* 事件方法
* @param c
*/
public void colleagueChanged(Colleague c ) {
colleague1.action();
colleague2.action();
}

public Colleague1 getColleague1() {
return colleague1 ;
}

public Colleague2 getColleague2() {
return colleague2 ;
}
}

/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:24:50
* <p/>
* note: 抽象同事角色
* 每个同事对象 仅知道调停者
* 而不知道其他同事对象
*/
public abstract class Colleague {
private Mediator mediator;

public Colleague(Mediator m) {
mediator = m;
}

/**
* 当前同时对象发生变化时，通知调停者
*/
public void change() {
mediator.colleagueChanged(this);
}

/**
* 行动方法，一个同事对象在得知其他同事对象有变化时
* 会执行此方法
*/
public abstract void action();

public Mediator getMediator() {
return mediator;
}
}

/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:25:00
* <p/>
* note: 具体同事角色
*/
public class Colleague1 extends Colleague {
public Colleague1(Mediator m) {
super(m);
}

public void action() {
System.out.println("This is an action from Colleague 1");
}
}

/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:25:10
* <p/>
* note: 具体同事角色
*/
public class Colleague2 extends Colleague {
public Colleague2(Mediator m) {
super( m );
}

public void action() {
System.out.println("This is an action from Colleague 2");
}
}

/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:25:20
* <p/>
* note: 具体同事角色
*/
public class Colleague3 extends Colleague {
public Colleague3(Mediator m) {
super( m );
}

public void action() {
System.out.println("This is an action from Colleague 3");
}
}

/**
* User: liuwentao@wentao365.com
* Date: 2008-12-9 Time: 15:34:30
* <p/>
* note: 客户端角色
*/
public class Client {

public static void main(String args[]) {
ConcreteMediator mediator = new ConcreteMediator();
mediator.createConcreteMediator();

Colleague c1 = new Colleague1(mediator);
Colleague c2 = new Colleague2(mediator);

mediator.colleagueChanged(c1);
}
}