title: How to prevent concurrent execution of a job in Grails?
body: <p>I have a quartz job in grails, that needs to be executed in every 5s, but I need this sequentially. In some situations the execution of the job exceeds this 5s, in this case I dont't want to be executed while the previouse exection is not finished. How to configure this in grails?</p>
  
  <p>(Of course the whole magic could be done with a static volatile flag, but is not a very elegant way to do this)
  (Also how can I configure for the job to be singleton?)</p>
  
  <p>thx</p>