/// <summary>
/// Registers a listener for a specific event
/// </summary>
/// <param name="eventType">Event the listener is listening for</param>
/// <param name="listener">Listener receiving messages for the specified event</param>
public void RegisterListener(EventType eventType, IEventHandler listener)
{
List<IEventHandler> listeners = RegisterEvent(eventType);
if (listeners.Contains(listener))
throw new Exception(string.Format("Listener {0} already listen to event {1}", listener, eventType.EventName));
listeners.Add(listener);
}
/// <summary>
/// Create or get an event type instance
/// </summary>
/// <param name="name">Name of the event</param>
/// <returns>Return an instance of EventType</returns>
public static EventType CreateEvent(string name)
{
if (string.IsNullOrEmpty(name)) throw new ArgumentNullException("name");
EventType ev;
AvailableEvent.TryGetValue(name, out ev);
if (ev != null) return ev;
ev = new EventType(name);
AvailableEvent.Add(name, ev);
return ev;
}
/// <summary>
/// Unregisters an event, mediator will stop dispatching message for this event
/// </summary>
/// <param name="eventType">Event to unregister</param>
/// <returns>Return true if the event is unregistered, otherwise false</returns>
private bool UnregisterEvent(EventType eventType)
{
List<IEventHandler> listeners;
_eventListenersMap.TryGetValue(eventType.EventHash, out listeners);
return (listeners != null) && _eventListenersMap.Remove(eventType.EventHash);
}
/// <summary>
/// Registers a new event managed by the mediator, it will dispatches messages
/// for this event
/// </summary>
/// <param name="eventType">Event to register</param>
private List<IEventHandler> RegisterEvent(EventType eventType)
{
List<IEventHandler> listeners = GetListeners(eventType);
if (listeners != null)
return listeners;
listeners = new List<IEventHandler>();
_eventListenersMap.Add(eventType.EventHash, listeners);
return listeners;
}
/// <summary>
/// Gets list of listeners for a specific event
/// </summary>
/// <param name="eventType">Event type</param>
/// <returns>Returns a list of listeners if found otherwise null</returns>
private List<IEventHandler> GetListeners(EventType eventType)
{
List<IEventHandler> listeners;
_eventListenersMap.TryGetValue(eventType.EventHash, out listeners);
return listeners;
}
/// <summary>
/// Unregisters a listener for a specific event
/// </summary>
/// <param name="eventType">Event to stop listening for</param>
/// <param name="listener">Listener</param>
/// <returns>Return true if the listener stop listening, otherwise false</returns>
public void UnregisterListener(EventType eventType, IEventHandler listener)
{
List<IEventHandler> listeners = GetListeners(eventType);
if (listeners == null) return;
listeners.Remove(listener);
}
/// <summary>
/// Unregisters all listeners for a specific event
/// </summary>
/// <param name="eventType">Event to stop listening for</param>
public void UnregisterListener(EventType eventType)
{
List<IEventHandler> listeners = GetListeners(eventType);
if(listeners == null) return;
listeners.Clear();
}