themillhousegroup / mondrian   0.9.1

MIT License GitHub

Another layer over Play-ReactiveMongo supplying classic CRUD boilerplate for Mongo-persisted objects

Scala versions: 2.12 2.11


An extra layer supplying the classic CRUD operations for Play-ReactiveMongo objects.


Bring in the library by adding the following to your Play project's build.sbt.

For Scala 2.12 & Play 2.6.x (and Reactive Mongo 0.12.6):
libraryDependencies += "com.themillhousegroup" %% "mondrian" % "0.9.1"


Once you have mondrian added to your Play project, you can start using it like this:

Enable the ReactiveMongoModule in your application.conf

You may already have this if you've been using the vanilla Reactive Mongo Module:

play.modules.enabled += "play.modules.reactivemongo.ReactiveMongoModule" 

Define the mongodb.uri in your application.conf

If you're coming from Play-ReactiveMongo you'll already have something appropriate in your application.conf, e.g.:

mongodb.uri="mongodb://user:[email protected]:12345/mydb"

Define a model object that extends the MongoEntity trait

You may already have models defined. A MongoEntity simply includes an _id: Option[MongoId] field like this:

import com.themillhousegroup.mondrian.{MongoEntity, MongoId}

case class Vehicle(
  val _id: Option[MongoId],
  val name: String,
  val manufacturer:Manufacturer,
  val yearFirstOffered:Int,
  val yearLastOffered:Option[Int]) extends MongoEntity

Define an implicit Play-JSON Format for your new object

Again, you may have already written a Format if you've been sending/receiving JSON over HTTP. You can extend MongoJson to get the implicit conversion for the MongoId; perhaps something like this:

import play.api.libs.json.Json

object VehicleJson extends MongoJson {
  import ManufacturerJson.manufacturerFormat
  implicit val vehicleFormat = Json.format[Vehicle]

Extend TypedMongoService[T] appropriately

This Service joins together your domain object, the name of the MongoDB collection that will hold it, and the Format to read/write it.

If you just want basic CRUD operations defined for your model object, you just need ONE line of code (plus the appropriate imports):

For Play 2.4.x:
import com.themillhousegroup.mondrian._
import models.VehicleJson._ 
class VehicleService extends TypedMongoService[Vehicle]("vehicles")
For Play 2.5.x (dependency injection is required):
import javax.inject.Inject
import com.themillhousegroup.mondrian._
import models.VehicleJson._ 
class VehicleService @Inject() (val reactiveMongoApi:ReactiveMongoApi) extends TypedMongoService[Vehicle]("vehicles")

Because of the VehicleJson._ import, the compiler is able to find the implicit JSON Format it needs. You can supply it explicitly if you prefer, as shown next. Of course you can add extra methods that are useful; for example:

import javax.inject.Inject
import com.themillhousegroup.mondrian._
import models.VehicleJson 
class VehicleService @Inject() (val reactiveMongoApi:ReactiveMongoApi) extends TypedMongoService[Vehicle]("vehicles")(VehicleJson.vehicleFormat) {
  def findVehiclesFirstSoldIn(year:Int):Future[List[Vehicle]] = {
    listWhere(Json.obj("yearFirstOffered" -> year))

Note how the query is built by using the Play JSON library to create an object.

In the above example, the listWhere(JsValue) function from the superclass is being used, but there are many more that you can utilize, for example findOne(JsValue), cursorWhere(JsValue) and enumerateWhere(JsValue). See the next section for the details.

Inject your new Service into your Controller classes

For example:

class VehicleController @Inject()(val vehicleService:VehicleService) extends Controller {
  // ...

Available Methods

Public Methods

As soon as you extend TypedMongoService[T], your Service will have the following public methods available. All of them return Futures of some sort, in keeping with the Reactive philosophy.

Creation / Update
Method Returns Description
save(obj:T) Future[Boolean] Persist obj. If its _id is None, will insert. Else will update
save(objs:Iterable[T]) Future[Iterable[Boolean]] Persist each of the objs as per save
saveAndPopulate(obj:T) Future[Option[T]] Persist obj as per save, and return it with the _id field populated
saveAndPopulate(objs:Iterable[T]) Future[Iterable[Option[T]]] Persist each of the objs as per saveAndPopulate
saveIfNew(obj:T) Future[Option[T]] If no similar object found, save obj as per saveAndPopulate. Otherwise, return the existing object from the collection
Method Returns Description
countAll Future[Int] Count the number of objects in the collection
countWhere(jsQuery:JsValue) Future[Int] Count the number of matches for jsQuery
cursorWhere(jsQuery:JsValue, size: Option[Int] = None, startFrom: Option[Int] = None, sortWith: Option[JsObject] = None, jsProjection: Option[JsValue] = None) Cursor[T] Returns a reactivemongo.api.Cursor of jsQuery matches
enumerateWhere(jsQuery:JsValue, size: Option[Int] = None, startFrom: Option[Int] = None, sortWith: Option[JsObject] = None) Enumerator[T] Returns a play.api.libs.iteratee.Enumerator of jsQuery matches
findOne(jsQuery:JsValue) Future[Option[T]] Attempt to find one object that matches jsQuery
findOne(example:T) Future[Option[T]] Attempt to find one object that matches the example
findById(id:String) Future[Option[T]] Attempt to find the object identified by id
findById(ids:Iterable[String]) Future[Iterable[T]] Attempt to find as many matches as possible for the supplied IDs
findByIdInOrder(ids:Iterable[String]) Future[Iterable[Option[T]]] Attempt to find each object denoted by its ID - a None in any position means no object was found for the corresponding ID
listAll Future[Seq[T]] Returns all in the collection
listAll(size: Option[Int] = None, startFrom: Option[Int] = None) Future[Seq[T]] Returns all in the collection, paginated
listWhere(jsQuery:JsValue, size: Option[Int] = None, startFrom: Option[Int] = None, sortWith: Option[JsObject] = NonejsProjection: Option[JsValue] = None) Future[Seq[T]] Returns jsQuery matches with optional pagination & sorting
Method Returns Description
deleteById(id:String) Future[Boolean] Delete the object identified by id
deleteWhere(jsQuery:JsValue) Future[Boolean] Delete all objects matching jsQuery

Protected Methods

Your Service that extends TypedMongoService[T] also gets access to protected methods to make writing additional T-specific methods easy:

Method Returns Description
findAll reactivemongo.api.collections.GenericQueryBuilder Get a GQB for all objects in the collection
findWhere(jsQuery:JsValue) reactivemongo.api.collections.GenericQueryBuilder Get a GQB for matching objects in the collection

A note about Write Concerns

By default, Mondrian uses the same MongoDB Write Concern as Play-ReactiveMongo - which is (currently) Acknowledged.

Should you wish to specify a different level of Write Concern, override the defaultWriteConcern in your Service, like this:

import com.themillhousegroup.mondrian._
import models.VehicleJson 
import reactivemongo.api.commands.WriteConcern
class VehicleService extends TypedMongoService[Vehicle]("vehicles")(VehicleJson.vehicleFormat) {

  // Writes will be written to the journal and we'll wait until
  // one Mongo instance has acknowledged this write.
  override val defaultWriteConcern = WriteConcern.Journaled 
  // ...


For an entity defined as:

case class ExampleEntity (
  _id: Option[MongoId],
  createdAt: DateTime,
  foo: Long,
  bar: String,
  bazzes: Seq[HeavyweightBaz]
) extends MongoEntity

Here's how some common service operations might look:

class ExampleEntityService @Inject() (val reactiveMongoApi:ReactiveMongoApi)
  extends TypedMongoService[ExampleEntity]("exampleEntities") {

  // Return the 'n' most recently-created documents:
  def listMostRecent(howMany:Option[Int]): Future[Seq[ExampleEntity]] = {
      Some(Json.obj("createdAt" -> -1)),
      Some(Json.obj("bazzes" -> 0)) // Drop this heavyweight array - saves a lot of latency
  // Find documents that have a 'bar' value of "Cat" OR "Dog"
  def listCatsAndDogs: Future[Seq[ExampleEntity]] = {
    // Create a MongoDB '$or' using standard Play JSON:
    val catsOrDogsQuery = Json.obj(
      "$or" -> Json.arr (
        Json.obj ("bar" -> JsString("Cat")),
        Json.obj ("bar" -> JsString("Dog"))


Add the following to your logback.xml to enable the maximum level of logging in Mondrian. In particular you'll see the gory details of the save and saveAndPopulate functions, which might help in debugging issues with persistence:

<logger name="com.themillhousegroup.mondrian" level="TRACE" />