dispatcher

Dispatcher.scala

package flux

/**
 * Created by IntelliJ IDEA.
 * User: xf
 * Date: 14/10/20
 * Time: 下午5:49
 */

trait Payload[T] {
  def content: T
}

trait Dispatcher {
  var _lastID = 1
  var _prefix = "ID_"
  var isDispatching = false

  type Callback[T] = T => Unit

  var callbacks = Map.empty[String, Callback[_]]
  var _isPending = Map.empty[String, Boolean]
  var _isHandled = Map.empty[String, Boolean]
  var _pendingPayload: Any

  def register[T: Payload](callback: Callback[T]): Unit = {
    val newId = s"$_prefix$_lastID"
    callbacks = callbacks.updated(newId, callback)
    _lastID += 1
  }

  def unregister(id: String): Unit = {
    callbacks = callbacks - id
  }

  def waitFor(ids: Seq[String]): Unit = {

  }

  def dispatch[T: Payload](payload: T): Unit = {
    _startDispatching(payload)
    try {
      for((id, callback) <- callbacks if !_isPending(id)) {
        _invokeCallback(id)
      }
    } finally {
      _stopDispatching()
    }
  }

  protected def _invokeCallback(id: String): Unit = {
    _isPending = _isPending.updated(id, true)
    callbacks(id).apply(_pendingPayload)
    _isHandled = _isHandled.updated(id, true)
  }

  protected def _startDispatching[T: Payload](payload: T):Unit = {
    val unset = {case (k,v) => (k, false)}
    _isPending.map(unset)
    _isHandled.map(unset)
    _pendingPayload = payload
    isDispatching = true
  }

  protected def _stopDispatching(): Unit = {
    _pendingPayload = null
    isDispatching = false
  }

}