Blog scheduler

approach2-crontab-monitoring-thread.java

class JobRunnable implements Runnable
{
    private final Job job;
    public JobRunnable(Job job)
    {
        this.job = job;
    }
  
    @Override
    void run()
    {
        while(true)
        {
            Thread.sleep(job.getNextExecutionTime() - currentTime());
            job.execute();
            job.setNextExecutionTime(currentTime() + job.getExecutionInterval());
        }
    }
}


public CrontabRunnable implements Runnable
{
    private final ExecutorService executorService = Executors.newFixedThreadPool(4);
    @Override
    void run()
    {  
        while(true)
        {
            newJob = getNewJobFromCrontabFile() // blocking call
            executorService.execute(new JobRunnable(newJob));
        }
    }
}