domain vs. controller vs service - Grails: querying for property

Question

Hi, folllowing scenario to query for list of items from domain:

class A {
  SortedSet items
}

Second line is code to be used in GSP

A1) domain and namedQuery

  static namedQueries = {
    filteredListItems { params ->
      ...
    }
  }

  A.filteredListItems(params)

A2) domain methode

  def filteredListItems = { params ->
    return this.items
  }

A.filteredListItems(params)

B) controller (or with criteria)

  def as = A.findAllByFilter(filter,params)

  as.listItems()

C) service

What is most recommended to be used as if there are more than one location where I need to query for "filteredItems"?

What about following concerns

• calculations with the results should be done only once if
• params need to be passed
• "total" is needed for paging

Thanks a lot Sebastian