Play Framework: Arrow ("->") in routing

Question

The Play + Java + CRUD Activator has the following route file, and I don't understand what -> does in it.

# Routes
# This file defines all application routes (Higher priority routes first)
# ~~~~

# Home page
# Home page
GET     /               controllers.Application.index()
# CRUD Controllers and REST API
->     /                play.crud.Routes

Answer 1

In my opinion, the Play documentation for this is poor. I will explain based on a nice sample on Github.

In conf/routes you may have:

->         /admin                admin.Routes
->         /customer             customer.Routes
->         /common               common.Routes

then, for example, admin.Routes, you can resolve as follows:

Look for the definition for admin which is in Build.sbt:

// Admin Portal
lazy val admin = project.in(file("modules/admin"))
  .dependsOn(common)

You see that it's in modules/admin. Head over to modules/admin/conf/routes where you'll see more routes:

GET        /index               controllers.admin.Application.getIndex()

So, Play puts that together with the original path /admin becoming /admin/index. That is, if you bring up /admin/index in the browser, controllers.admin.Application.getIndex() will be used to serve this route.