/// <summary>
/// Validates the specified handler.
/// </summary>
/// <typeparam name="T">Type of the message to process.</typeparam>
/// <param name="handler">The handler.</param>
/// <exception cref="EventBusException"></exception>
private void ValidateMessageHandler <T>(IEventBusMessageHandler <T> handler) where T : IEventBusMessage
{
if (!handler.IsValid())
{
string logMessage = $"Can't add invalid handler for message tag {handler.MessageTagInfo.MessageTagString} " +
$"and event id {handler.MessageEventId} " +
$"from {handler.CreatorId}; please, set all needed fields properly.";
throw new EventBusException(logMessage);
}
}
/// <summary>
/// Adds the event message hanlder for the specific message event ID.
/// </summary>
/// <param name="handler">The handler.</param>
public void AddMessageHanlder <T>(IEventBusMessageHandler <T> handler) where T : IEventBusMessage
{
this.ValidateMessageHandler(handler);
if (!this.Connect())
{
throw new EventBusException($"Can't establish connection to finish adding message handler for {handler}");
}
this.EventHandlers.Add(handler as IEventBusMessageHandler <IEventBusMessage>);
this.OnMessageHandlerAdd(handler);
}
/// <summary>
/// Performs bus-specific ops after addition of event message handler.
/// </summary>
/// <typeparam name="T">Type of the message to process.</typeparam>
/// <param name="handler">The handler.</param>
protected override void OnMessageHandlerAdd <T>(IEventBusMessageHandler <T> handler)
{
string messageQueue = handler.MessageTagInfo.MessageTagString;
if (this.EventHandlers.Count(h => h.MessageTagInfo.MessageTagString == handler.MessageTagInfo.MessageTagString) == 1)
{
this.subscriberChannel.ExchangeDeclare(this.BusId, ExchangeType.Direct);
string tag = this.subscriberChannel.BasicConsume(messageQueue, false, this.basicConsumer);
consumerTags[messageQueue] = tag;
}
this.subscriberChannel.QueueBind(messageQueue, this.BusId, handler.MessageEventId);
}
/// <summary>
/// Performs bus-specific ops after addition of event message handler.
/// </summary>
/// <param name="handler">The handler.</param>
protected override void OnMessageHandlerAdd <T>(IEventBusMessageHandler <T> handler)
{
List <string> subscriptions = this.consumer.Subscription ?? new List <string>();
string topic = handler.MessageTagInfo.MessageTagString;
if (!subscriptions.Contains(topic))
{
subscriptions.Add(topic);
this.consumer.Subscribe(subscriptions);
}
if (this.EventHandlers.Count == 1)
{
this.StartNewPoll();
}
}
/// <summary>
/// Performs bus-specific ops after addition of event message handler.
/// </summary>
/// <typeparam name="T">Type of the message to process.</typeparam>
/// <param name="handler">The handler.</param>
protected override void OnMessageHandlerAdd <T>(IEventBusMessageHandler <T> handler)
{
this.pubSubClient.Subscribe(new RedisChannel(handler.MessageEventId, RedisChannel.PatternMode.Literal),
this.handlerAction);
}
/// <summary> /// Performs bus-specific ops after addition of event message handler. /// </summary> /// <typeparam name="T">Type of the message to process.</typeparam> /// <param name="handler">The handler.</param> protected abstract void OnMessageHandlerAdd <T>(IEventBusMessageHandler <T> handler) where T : IEventBusMessage;
