title: Grails Helper method/class to be used inside the Service
body: <p>I need some advice on design perspective regarding Grails Services.</p>
  
  <p>At some point..I calculate about 5-6 different lists based on ONE object, for example modified, deleted, added people.</p>
  
  <p>I'm not allowed to add anything to the database layer, so domain class is not an option (transient, etc). </p>
  
  <p>These lists are different for each time the method in service is called.</p>
  
  <p>What would be the best way and where to implement: A helper storage class for these lists. I can set them once in service, and get them from another method in service. </p>
  
  <p>Is there a better way when working in the Services? The object to the class should not be created locally inside a method otherwise i don't have access to it later</p>