C# Hub

README.md

C# Hub

Usage:

var hub = new Hub();

hub.On((YourMessage message) => {
  // do stuff
});

// or

hub.On<YourMessage>(message => {
  // do stuff
});

hub.Notify(new YourMessage());

Available methods are On, Once, Off, Notify and Dispose.

The Hub class meant to be used while Hub<T> class meant to be inherited.

Hub.cs

using System;
using System.Collections.Generic;

public abstract class Hub<T> : IDisposable where T : Hub<T>
{
    private Dictionary<Type, List<MulticastDelegate>> subscribers = new Dictionary<Type, List<MulticastDelegate>>();
    private bool disposed;

    private void CheckDisposed()
    {
        if (disposed)
        {
            throw new ObjectDisposedException(GetType().FullName);
        }
    }

    public T On<M>(Action<M> action)
    {
        CheckDisposed();

        var type = typeof(M);

        if (!subscribers.ContainsKey(type))
        {
            subscribers[type] = new List<MulticastDelegate>();
        }

        subscribers[type].Add(action);

        return (T)this;
    }

    public T Once<M>(Action<M> action)
    {
        CheckDisposed();

        Action<M> proxy = null;

        proxy = message =>
        {
            action(message);
            Off(proxy);
        };

        return this.On(proxy);
    }

    public T Off<M>(Action<M> action)
    {
        CheckDisposed();

        var type = typeof(M);

        if (subscribers.ContainsKey(type))
        {
            subscribers[type].Remove(action);
        }

        return (T)this;
    }

    public T Notify<M>(M message)
    {
        CheckDisposed();

        var type = typeof(M);

        if (subscribers.ContainsKey(type))
        {
            foreach (var action in subscribers[type].ToArray())
            {
                action.DynamicInvoke(message);
            }
        }

        return (T)this;
    }

    public virtual void Dispose()
    {
        if (!disposed)
        {
            subscribers = null;
            disposed = true;
        }
    }
}

public sealed class Hub : Hub<Hub>
{
}

HubTest.cs

using System;

class HubTest
{
    class HelloWorldMessage
    {
    }

    static void Main(string[] args)
    {
        var hub = new Hub();

        var notified = 0;

        var action = new Action<HelloWorldMessage>(message =>
        {
            notified++;
        });

        hub.On(action);

        hub.Notify(new HelloWorldMessage());

        if (notified != 1)
        {
            throw new Exception();
        }

        hub.Off(action);

        if (notified != 1)
        {
            throw new Exception();
        }

        hub.Once(action);

        hub.Notify(new HelloWorldMessage());

        if (notified != 2)
        {
            throw new Exception();
        }

        hub.Notify(new HelloWorldMessage());

        if (notified != 2)
        {
            throw new Exception();
        }
    }
}