设计模式之观察者模式

来源：互联网发布：淘宝快捷支付怎么取消编辑：程序博客网时间：2024/06/09 16:19

public interface IObserver {
public void update(IObserverable observerable);
}

public class PersonObserver implements IObserver {

   @Override
   public void update(IObserverable observerable) {
       System.out.println("个人收到预警 "+observerable.reportTemperature());
   }

}

public class CompanyObserver implements IObserver {

   @Override
   public void update(IObserverable observerable) {
       System.out.println("公司收到预警 "+observerable.reportTemperature());
   }

}

public class GovermentObserver implements IObserver {

   @Override
   public void update(IObserverable observerable) {
       System.out.println("政府收到预警 "+observerable.reportTemperature());
   }

}

/**

* 被观察者
* @author 熊诗言
*
*/
public interface IObserverable {
   public boolean add(IObserver observer);
   public boolean remove(IObserver observer);
   public void notifyAllObserver();

   public void setTemperature(float temperature);
   public String reportTemperature();
}

public class Subject implements IObserverable {

   private float temperature;
   private String waringLevel;
   private List<IObserver> list = new ArrayList<IObserver>();
   @Override
   public boolean add(IObserver observer) {
       if(observer!=null && !list.contains(observer)){
           return list.add(observer);
       }
       return false;
   }

   @Override
   public void notifyAllObserver() {
       System.out.println("气象部门发布 " + waringLevel + "警报");
       Iterator<IObserver> itr = list.iterator();
       while (itr.hasNext()) {
           itr.next().update(this);

       }
   }

   @Override
   public boolean remove(IObserver observer) {
       return this.list.remove(observer);
   }

   @Override
   public String reportTemperature() {
       return "温度："+this.temperature;
   }

   @Override
   public void setTemperature(float temperature) {
       this.temperature = temperature;
       this.invoke();
   }

   private void invoke() {
       if(this.temperature>=35){
           if(this.temperature>=35 && this.temperature<37 ){
               this.waringLevel = "黄色";
           }else if(this.temperature>=37 && this.temperature<40 ){
               this.waringLevel = "橙色";
           }else {
               this.waringLevel = "红色";
           }
           this.notifyAllObserver();
       }
   }

}

测试

public class Client {
   public static void main(String[] args) {
       IObserverable observerable = new Subject();
       observerable.add(new PersonObserver());
       observerable.add(new GovermentObserver());
       observerable.add(new CompanyObserver());
       int i = 0;
       Random random = new Random();
       while(++i<10){
           observerable.setTemperature(random.nextInt(45));
       }
   }

}

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