def findMap[T](by: QueryParam[A]*)(f: A => Box[T])
Your function, f, will be called as each row is pulled back from the
database. If your function returns Empty, the row will not be included in
the final result. You can also do fun stuff like:
MyModel.findMap(){
row -> row.name.is match {
case x if x.length < 4 => Full(x)
case _ => Empty
}}
This will return a List[String] for all the people with short names. Your
function is called as each row is processed, so the whole list is not loaded
into memory.
If you wanted to simulate a foreach here, you'd just return Empty from the
function every time.
On Wed, Jan 27, 2010 at 9:58 PM, Naftoli Gugenheim <naftoli...@gmail.com>wrote:
> MetaMapper has a findAll method, which creates a statement based on its
> parameters, and then iterates over the ResultSet creating Mappers and
> putting them into a List.
> It would be neat if it was possible to process the generated Mappers one by
> one instead of loading them into a list. This way large ResultSets don't
> need to result in a big List in memory.
> Is such a thing possible today? If not, what would it take to implement?
> One approach would be foreach/map/flatMap methods. Another would be a find
> method that returns a lazy list or an Iterator.
> Thanks.
>
>
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