alisol911/play-cake-pattern

Play! Scala cake pattern implementation

Example Play! Scala app with Cake Pattern

I was looking at these tutorials:

• http://playlatam.wordpress.com/tag/cake-pattern/
• http://www.cakesolutions.net/teamblogs/2011/12/19/cake-pattern-in-depth/
• http://jonasboner.com/2008/10/06/real-world-scala-dependency-injection-di/

... and got curious enough to implement it myself in the latest release version of Play! Scala to date (2.2.0-M2). It makes use of some 2.2 additions like Action.async, database evolutions including generating data, has tests on different layers of the cake pattern in order to look at how dependency injection might be used, actually uses a real entity with implicit json read/writes (all the examples I found lacked the actual definition of the entity they were passing around) and lastly I configured the app to run an H2 in memory database with MySQL compatibility, so if you want to check this out and run it on something else that should be easy enough.

How this is organized

/app
  /components
    Default            - trait to extend all the default services
                         and repositories you would want to use
                         by default.
  /controllers
    Application        - defines app config (namely inheriting
                         components.Default) for all other
                         controllers
    Landing            - renders HTML for landing route
    Users              - JSON API for Users, makes use of UserService
                         (and thereby the UserRepository)
  /entities
    User               - the only entity in the entire app, has
                         implicit JSON serialization and Anorm SQL
                         Result mapping
  /repositories
    UserRepository     - traits and classes for handling data layer
                         for Users, implementation of Anorm
  /services
/conf                  - some configs
/project
  Build.scala          - note that while Play 2.x bundles specs2
                         and mockito for testing it does not do so for
                         simply running the app
/test
  /repositories
    UserRepositorySpec - bit redundant to write tests on this with
                         a FakeApplication since the routes spec covers
                         the same code, was just being thorough :)
  /routes
    LandingRouteSpec   - just being thorough, covers the only HTML
                         route
    UserRouteSpec      - covers the JSON Users API with FakeApplication
                         instances
  /services
    UserServiceSpec    - unit tests the UserService by mocking
                         UserRepository with Mockito (doesn't really test
                         anything, just showing for demo purposes)
  package.scala        - helper method for FakeApplication config