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