Insert document with ReactiveMongo does not use BSONWriter or Reader - mongodb

Question

I have the following class:
case class DeviceRegistration(deviceData: DeviceData,
pin: String,
created: DateTime) {}
Type DeviceData is defined simply as 4 string fields.
I've been trying unsuccessfully to insert a type of DeviceRegistration to a mongo collection. I want to make sure the date is stored as a ISODate and not a NumberLong, so I implemented custom readers and writers.
implicit object DeviceDataWriter extends BSONDocumentWriter[DeviceData] {
def write(data: DeviceData): BSONDocument = BSONDocument(
DEVICE_ID_KEY -> data.deviceId,
MODEL_KEY -> data.model,
BRAND_KEY -> data.brand,
MANUFACTURER_KEY -> data.manufacturer)
}
implicit object DeviceRegistrationWriter extends BSONDocumentWriter[DeviceRegistration] {
def write(registration: DeviceRegistration): BSONDocument = BSONDocument(
DEVICE_DATA_KEY -> registration.deviceData,
PIN_KEY -> registration.pin,
CREATED_KEY -> BSONDateTime(registration.created.getMillis))
}
implicit object DeviceDataReader extends BSONDocumentReader[DeviceData] {
def read(doc: BSONDocument): DeviceData = {
val deviceId = doc.getAs[String](DEVICE_ID_KEY).get
val model = doc.getAs[String](MODEL_KEY)
val brand = doc.getAs[String](BRAND_KEY)
val manufacturer = doc.getAs[String](MANUFACTURER_KEY)
DeviceData(deviceId, model, brand, manufacturer)
}
}
implicit object DeviceRegistrationReader extends BSONDocumentReader[DeviceRegistration] {
def read(doc: BSONDocument): DeviceRegistration = {
val deviceData = doc.getAs[DeviceData](DEVICE_DATA_KEY).get
val pin = doc.getAs[String](PIN_KEY).get
val created = doc.getAs[BSONDateTime](CREATED_KEY).map(dt => new DateTime(dt.value))
DeviceRegistration(deviceData, pin, created.get)
}
}
I'm trying to insert the document with the following code:
def save(deviceRegistration: DeviceRegistration): Future[DeviceRegistration] = {
deviceRegistrations.insert(deviceRegistration).map(result => deviceRegistration)
}
To retrieve, I'm doing this:
def findDeviceRegistrationRequest(deviceConfirmationData: DeviceConfirmationData) = {
deviceRegistrations.find(BSONDocument("pin" -> deviceConfirmationData.pin))
.one[DeviceRegistration](ReadPreference.Primary)
}
The record is stored as this:
{ "_id" : ObjectId("56dea8d0d8cadd6ff70690d8"), "deviceData" : { "deviceId" : "kdsajkldjsalkda" }, "pin" : "9914", "created" : NumberLong("1457432783921") }
The created date is clearly not being serialized by my writer. It seems reactivemongo is using some default writer.
Likewise, when I read, I get an exception:
Caused by: java.lang.RuntimeException: (/created,List(ValidationError(List(error.expected.date),WrappedArray())))
So it's clearly also not using my reader.
I didn't have any luck googling around. What am I missing?
I also tried to find a way to specifically set the writer and reader I want to use (instead of relying on the implicit mechanism), but I was not able to figure it out.
Any pointers in the right direction would be most appreciated.