How do I map my objects correctly to make a list of objects work in mongo + play2 - mongodb

Question

I'm trying to write readers/writers for my case classes after reading:
https://github.com/sgodbillon/reactivemongo-demo-app/blob/master/app/models/articles.scala
https://github.com/zenexity/ReactiveMongo/blob/master/driver/samples/BSON.scala
but I'm having trouble in making it work.
I have a leadCategory that can consist of several word objects.
package models
import org.joda.time.DateTime
import reactivemongo.bson._
import reactivemongo.bson.handlers.{BSONWriter, BSONReader}
import reactivemongo.bson.BSONDateTime
import reactivemongo.bson.BSONString
LeadCategory:
case class LeadCategory(
id: Option[BSONObjectID],
categoryId: Long,
categoryName: String,
creationDate: Option[DateTime],
updateDate: Option[DateTime],
words: List[Word]
)
object LeadCategory {
implicit object LeadCategoryBSONReader extends BSONReader[LeadCategory] {
def fromBSON(document: BSONDocument): LeadCategory = {
val doc = document.toTraversable
LeadCategory(
doc.getAs[BSONObjectID]("_id"),
doc.getAs[BSONLong]("caregoryId").get.value,
doc.getAs[BSONString]("categoryName").get.value,
doc.getAs[BSONDateTime]("creationDate").map(dt => new DateTime(dt.value)),
doc.getAs[BSONDateTime]("updateDate").map(dt => new DateTime(dt.value)),
doc.getAs[List[Word]]("words").toList.flatten)
}
}
implicit object LeadCategoryBSONWriter extends BSONWriter[LeadCategory] {
def toBSON(leadCategory: LeadCategory) = {
BSONDocument(
"_id" -> leadCategory.id.getOrElse(BSONObjectID.generate),
"caregoryId" -> BSONLong(leadCategory.categoryId),
"categoryName" -> BSONString(leadCategory.categoryName),
"creationDate" -> leadCategory.creationDate.map(date => BSONDateTime(date.getMillis)),
"updateDate" -> leadCategory.updateDate.map(date => BSONDateTime(date.getMillis)),
"words" -> leadCategory.words)
}
}
Word:
case class Word(id: Option[BSONObjectID], word: String)
object Word {
implicit object WordBSONReader extends BSONReader[Word] {
def fromBSON(document: BSONDocument): Word = {
val doc = document.toTraversable
Word(
doc.getAs[BSONObjectID]("_id"),
doc.getAs[BSONString]("word").get.value
)
}
}
implicit object WordBSONWriter extends BSONWriter[Word] {
def toBSON(word: Word) = {
BSONDocument(
"_id" -> word.id.getOrElse(BSONObjectID.generate),
"word" -> BSONString(word.word)
)
}
}
}
I'm getting a compile error at:
"words" -> leadCategory.words)
stating:
Too many arguments for method apply(ChannelBuffer)
Type mismatch found: (String, List[Words]) required required implicits.Producer[(String, BsonValue)]
What have I missed? Maybe I have misunderstood the docs...

Answer 1

Try to declare the "Word" implicit objects above the "LeadCategory", if you are putting all of it in the same file.
Scala cannot find the implicit objects for the List[Word] - assuming you are using ReactiveMongo 0.9.

Answer 2

All of your types should a derivative of a BSON type. I think you want to use BSONArray instead of a List.