score:7

Answer coming from : http://grokbase.com/t/gg/rogue-users/1367nscf80/how-to-update-a-record-with-mongocaseclassfield-when-case-class-contains-a-scala-enumeration#20130612woc3x7utvaoacu7tv7lzn4sr2q

But more convenient directly here on StackOverFlow:


Sorry, I should have chimed in here sooner.

One of the long-standing problems with Rogue was that it was too easy to accidentally make a field that was not serializable as BSON, and have it fail at runtime (when you try to add that value to a DBObject) rather than at compile time.

I introduced the BSONType type class to try to address this. The upside is it catches BSON errors at compile time. The downside is you need to make a choice when it comes to case classes.

If you want to do this the "correct" way, define your case class plus a BSONType "witness" for that case class. To define a BSONType witness, you need to provide serialization from that type to a BSON type. Example:

 case class TestCC(v: Int)

 implicit object TestCCIsBSONType extends BSONType[TestCC] {
   override def asBSONObject(v: TestCC): AnyRef = {
     // Create a BSON object
     val ret = new BasicBSONObject
     // Serialize all the fields of the case class
     ret.put("v", v.v)
     ret
   }
 }

That said, this can be quite burdensome if you're doing it for each case class. Your second option is to define a generic witness that works for any case class, if you have a generic serialization scheme:

 implicit def CaseClassesAreBSONTypes[CC <: CaseClass]: BSONType[CC] =
new BSONType[CC] {
   override def asBSONObject(v: CC): AnyRef = {
     // your generic serialization code here, maybe involving formats
   }
 }

Hope this helps,


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