Service/Controller

The MessageController handles all the URLs, or you can say operations, related to messages. To have a separation of concern in our code. The actual job of saving the message, that is the database operations, is delegated to the respective Repository class (MessageRepository):

    /**
      * Exposes the operations related to creating and showing
      * messages through URLs using REST
      */
    @RestController
    @RequestMapping("/message")
    class MessageController(val repository: MessageRepository) {

      val broadcaster = ReactiveBroadcaster()

    /**
      * Creates new message and saves it into DB
      */
    @PostMapping
    @ResponseStatus(CREATED)
    fun create(@RequestBody message: Message): Message {
      val msg = repository.insert(message)
      broadcaster.send(msg)
      return msg
    }

    /**
      * Get list of all the messages
      */
    @GetMapping
    fun list() = repository.findAll()

    /**
      * Get list of messages in the given bounds
      */
    @GetMapping("/bbox/{xMin},{yMin},{xMax},{yMax}")
    fun findByBoundingBox(@PathVariable xMin: Double, @PathVariable  
     yMin: Double,
     @PathVariable xMax: Double, @PathVariable  
     yMax: Double)
     = repository.findByBoundingBox(PGbox2d(Point(xMin, yMin), 
     Point(xMax, yMax)))

        /**
          * Subscribes to receive the updates regarding the messages
          */
     @GetMapping("/subscribe")
     fun subscribe()= broadcaster.subscribe()
    }

@GetMapping and @PostMapping annotations are just method-specific shortcuts for @RequestMapping annotations available since Spring Framework 4.3.