A side by side comparison (now that I finally got it figured out!) of Play Framework v2.2.x promise unwrapping in Java and Scala. Hopefully this will be able to save some of you a bunch of mind numbing ponderings and failures.

<3 /dev/alias

https://gist.github.com/0xdevalias/1d3b44312d8a68ddbaa5

# Java/Scala Future/Promise Map

A side by side comparison (now that I finally got it figured out!) of Play Framework v2.2.x promise unwrapping in Java and Scala.
Java
  public Promise<ObjectNode> getEmployees(final Optional<String> filterEmail)
	{
		// Call the webservice
		Promise<Response> promiseOfEmployees = this.xero.getEmployees(filterEmail);
		
		// Map into an ObjectNode
		Promise<ObjectNode> promiseJson = promiseOfEmployees.map(new F.Function<WS.Response, ObjectNode>()
		{
			@Override
			public ObjectNode apply(final Response response) throws Throwable
			{
				JsonNode responseJson = response.asJson();

				ObjectNode json = Json.newObject();

				json.put("foo", "bar");

				return json;
			}
		});

		// Return
		return promiseJson;
	}

Scala
def getEmployees(filterEmail: Optional[String]): Promise[ObjectNode] = {
    // Call the webservice
    val promiseOfEmployees: Promise[Response] = this.xero.getEmployees(filterEmail)
    
    // Map into an ObjectNode
    val promiseJson: Future[ObjectNode] = promiseOfEmployees.wrapped().map { response =>
      val jsonResponse: JsonNode = response.asJson();
      val json: ObjectNode = Json.newObject()
      json.put("foo", "bar");
      json // Return
    }

    // Return
    return Promise.wrap(promiseJson)
  }

Scala (Implicit)
  def getEmployees(filterEmail: Optional[String]): Promise[ObjectNode] = {
    // Call the webservice
    val promiseOfEmployees = this.xero.getEmployees(filterEmail)

    // Map into an ObjectNode
    val promiseJson = promiseOfEmployees.wrapped().map { response =>
      val jsonResponse = response.asJson();
      val json = Json.newObject()
      json.put("foo", "bar");
      json // Return
    }

    // Return
    return Promise.wrap(promiseJson)
  }

<3 Glenn / devalias