停止/啟動在EJB 3.1中使用@Schedule注釋的所有方法

Question

我需要停止並啟動所有在EJBs類中以@Schedule注釋的方法。

例如，我想停止並在幾分鍾后重新啟動該EJB類中的doIt（）方法：

@Stateless
public class MySchedule {

  @Schedule(second = "*/15", minute = "*", hour = "*", persistent = false)
  public void doIt(){
    // do anything ...
  }

}

我嘗試使用EJB Interceptor，例如以下代碼：

@Stateless
public class MySchedule {

  @Schedule(second = "*/15", minute = "*", hour = "*", persistent = false)
  @Interceptors(MyInterceptor.class)
  public void doIt(){
    // do anything ...
  }
}

public class MyInterceptor{
         @AroundInvoke
         public Object intercept(){
            System.out.println(" Schedule Intercepted");  
            Object result = context.proceed();
         }
}

但是@Schedule從未觸發過攔截方法

Answer 1

您可以做的是創建一個“容器”類，所有類都用@Scheduled注釋。 但是，中斷/退出方法的問題將取決於保持代碼運行或發出停止信號的條件/變量。

我會做類似的事情：

@Stateless
public class MySchedule implements Schedulable{
    boolean shouldRun = true;

    //This method should be present in the Schedulable interface
    @Override
    public synchronized boolean shouldBeRunning(boolean shouldRun){
      this.shouldRun = shouldRun;
    }

    //This method should also be in the Schedulable interface, so
    //you can invoke it wherever you need it.
    @Override
    @Schedule(second = "*/15", minute = "*", hour = "*", persistent = false)
    public void doIt(){
       /* If it runs a loop, you can break it like this: */
       while(shouldRun){
           //do anything
       }

       /* Otherwise you can break functionality of doIt and verify in each step: */
       if(shouldRun){
           //do anything step 1
       }

       if(shouldRun){
           //do anything step 2
       }

       if(shouldRun){
           //do anything step 3
       }
    }
}

“容器”類：

@Named
public class SchedulableContainer{
    @EJB
    MySchedule mySchedule;

    @EJB
    MyOtherSchedule myOtherSchedule;

    private Schedulable[] schedulables;

    @PostConstruct
    void initSchedulables(){
       schedulables = new Schedulable[]{ sched, sched2 };
    }

    void toggleSchedulables(boolean shouldRun){
        for(Schedulable sched: schedulables){
            sched.shouldBeRunning(shouldRun);
        }
    }

    public void stopSchedulables(){
        this.toggleSchedulables(false);
    }

    public void restartSchedulables(){
        this.toggleSchedulables(true);

        //Here you could read a property that tells you
        //how much should you delay to trigger MySchedule#doIt
        //again.
    }
}