一、前言：
中介者模式的注意事项和细节：
使用中介者模式可以将网状结构分离成星型结构。减少类的依赖，降低偶合，遵循了迪米特法则。
二、中介者模式：
2.1、UML 图：
2.2、代码实例：
Step 1) 创建 Colleague 抽象类：
public abstract
class Colleague {
private Mediator mediator
;
public String name
;
public Colleague(Mediator mediator
, String name
){
this.mediator
= mediator
;
this.name
= name
;
}
public Mediator
GetMediator(){
return this.mediator
;
}
public abstract
void SendMessage(int stateChange
);
}
Step 2) 创建 Alarm 实现类：
public class Alarm extends Colleague
{
public Alarm(Mediator mediator
, String name
) {
super(mediator
, name
);
mediator
.Register(name
, this);
}
public void SendAlarm(int stateChange
){
SendMessage(stateChange
);
}
@Override
public void SendMessage(int stateChange
) {
this.GetMediator().GetMassage(stateChange
, this.name
);
}
}
Step 3) 创建 CoffeeMachine 抽象类：
public class CoffeeMachine extends Colleague
{
public CoffeeMachine(Mediator mediator
, String name
) {
super(mediator
, name
);
}
@Override
public void SendMessage(int stateChange
) {
}
public void StartCoffee(){
System
.out
.println("It`s time to StartCoffee ! ");
}
public void finishCoffee(){
System
.out
.println("After 5 minutes ! ");
System
.out
.println("Coffee is ok ! ");
SendMessage(0);
}
}
Step 4) 创建 Curtains 实现类：
public class Curtains extends Colleague
{
public Curtains(Mediator mediator
, String name
) {
super(mediator
, name
);
mediator
.Register(name
, this);
}
@Override
public void SendMessage(int stateChange
) {
this.GetMediator().GetMassage(stateChange
, this.name
);
}
public void UpCurtains(){
System
.out
.println("I am holding Up Curtains ! ");
}
}
Step 5) 创建 TV 实现类：
public class TV extends Colleague
{
public TV(Mediator mediator
, String name
) {
super(mediator
, name
);
mediator
.Register(name
, this);
}
@Override
public void SendMessage(int stateChange
) {
this.GetMediator().GetMassage(stateChange
, this.name
);
}
public void StartTv(){
System
.out
.println("It`s time to StartTv ! ");
}
public void StopTv(){
System
.out
.println("It`s time to StopTv ! ");
}
}
Step 6) 创建 Mediator 抽象类：
public abstract
class Mediator {
public abstract
void Register(String colleagueName
, Colleague colleague
);
public abstract
void GetMassage(int stateChange
, String colleagueName
);
public abstract
void SendMessage();
}
Step 7) 创建 ConcreteMediator 抽象类：
public class ConcreteMediator extends Mediator
{
private HashMap
<String
, Colleague
> colleagueMap
;
private HashMap
<String
, String
> interMap
;
public ConcreteMediator(){
colleagueMap
= new HashMap
<String
, Colleague
>();
interMap
= new HashMap
<String
, String
>();
}
@Override
public void Register(String colleagueName
, Colleague colleague
) {
colleagueMap
.put(colleagueName
, colleague
);
if(colleague instanceof Alarm
){
interMap
.put("Alarm", colleagueName
);
interMap
.put("CpffeeMachine", colleagueName
);
}else if(colleague instanceof TV
){
interMap
.put("TV", colleagueName
);
}else if(colleague instanceof Curtains
){
interMap
.put("Curtains", colleagueName
);
}
}
@Override
public void GetMassage(int stateChange
, String colleagueName
) {
if(colleagueMap
.get(colleagueName
) instanceof Alarm
){
if(stateChange
== 0){
((CoffeeMachine
) (colleagueMap
.get(interMap
.get("colleagueName"))))
.StartCoffee();
((TV
) (colleagueMap
.get(interMap
.get("TV")))).StartTv();
}else if(stateChange
== 1){
((TV
) (colleagueMap
.get(interMap
.get("TV")))).StopTv();
}
}else if(colleagueMap
.get(colleagueName
) instanceof CoffeeMachine
){
((Curtains
) (colleagueMap
.get(interMap
.get("Curtains"))))
.UpCurtains();
}else if(colleagueMap
.get(colleagueName
) instanceof TV
){
}else if(colleagueMap
.get(colleagueName
) instanceof Curtains
){
}
}
@Override
public void SendMessage() {
}
}
Step 8) 创建 main 方法：
public class ClientTest {
public static void main(String
[] args
) {
Mediator mediator
= new ConcreteMediator();
Alarm alarm
= new Alarm(mediator
, "alarm");
CoffeeMachine coffeeMechine
= new CoffeeMachine(mediator
,
"coffeeMachine");
Curtains curtains
= new Curtains(mediator
, "curtains");
TV tv
= new TV(mediator
, "TV");
alarm
.SendAlarm(0);
coffeeMechine
.finishCoffee();
alarm
.SendAlarm(1);
}
}
• 由 ChiKong_Tam 写于 2020 年 10 月 22 日
