public void GetMessagesForSubscriberOfTopic(string topic, NewsSubscriber subscriber)
{
if (messagesQueue.Count == 0)
{
Console.WriteLine("No messages from publishers to display");
}
else
{
while (messagesQueue.Count != 0)
{
Message message = messagesQueue.Dequeue();
if (message.Topic.ToLower().Equals(topic.ToLower()))
{
HashSet <Subscriber> subscribersOfTopic = subscribersTopicMap[topic];
foreach (Subscriber _subscriber in subscribersOfTopic)
{
if (_subscriber.Equals(subscriber))
{
//add broadcasted message to subscriber message queue
List <Message> subscriberMessages = subscriber.SubscriberMessages;
subscriberMessages.Add(message);
subscriber.SubscriberMessages = subscriberMessages;
}
}
}
}
}
}
public void RemoveSubscriber(string topic, NewsSubscriber subscriber)
{
if (subscribersTopicMap.ContainsKey(topic))
{
HashSet <Subscriber> subscribers = subscribersTopicMap[topic];
subscribers.Remove(subscriber);
subscribersTopicMap[topic] = subscribers;
}
}
public static void Main(string[] args)
{
//Instantiate publishers, subscribers and PubSubService
IPublisher sportNewsPublisher = new NewsPublisher();
IPublisher politicalNewsPublisher = new NewsPublisher();
Subscriber sportSubscriber = new NewsSubscriber();
Subscriber politicsSubscriber = new NewsSubscriber();
Subscriber newsSubscriber = new NewsSubscriber();
//Declare Messages and Publish Messages to PubSubService
Message sportMsg1 = new Message("Sport", "Sport news 1");
Message sportMsg2 = new Message("Sport", "sport news 2");
Message politicsMsg3 = new Message("Politics", "politics 1223");
//
PubSubService pubSubService = new PubSubService();
sportNewsPublisher.publish(sportMsg1, pubSubService);
sportNewsPublisher.publish(sportMsg2, pubSubService);
politicalNewsPublisher.publish(politicsMsg3, pubSubService);
//Declare Subscribers
sportSubscriber.AddSubscriber("Sport", pubSubService);
politicsSubscriber.AddSubscriber("Politics", pubSubService);
newsSubscriber.AddSubscriber("Sport", pubSubService);
newsSubscriber.AddSubscriber("Politics", pubSubService);
//Trying unSubscribing a subscriber
//newsSubscriber.unSubscribe("Sport", pubSubService);
//Broadcast message to all subscribers. After broadcast, messageQueue will be empty in PubSubService
pubSubService.Broadcast();
//Print messages of each subscriber to see which messages they got
Console.WriteLine("Messages of Sport Subscriber are: ");
sportSubscriber.printMessages();
Console.WriteLine("\nMessages of Politics Subscriber are: ");
politicsSubscriber.printMessages();
Console.WriteLine("\nMessages of News Subscriber are: ");
newsSubscriber.printMessages();
Console.Write("\nPress Any Key:");
Console.ReadKey();
}
public void AddSubscriber(string topic, NewsSubscriber subscriber)
{
if (subscribersTopicMap.ContainsKey(topic))
{
HashSet <Subscriber> subscribers = subscribersTopicMap[topic];
subscribers.Add(subscriber);
subscribersTopicMap[topic] = subscribers;
}
else
{
HashSet <Subscriber> subscribers = new HashSet <Subscriber>();
subscribers.Add(subscriber);
subscribersTopicMap.Add(topic, subscribers);
}
}
