/// <summary>
/// Initializes a new instance of the <see cref="Subscription"/> class.
/// </summary>
/// <param name="handler">The change handler.</param>
/// <param name="filter">The MongoDB collection namespace wildcard filter.</param>
/// <exception cref="ArgumentNullException"><paramref name="handler"/> is <see langword="null" />.</exception>
public Subscription(IHandleChange handler, string filter)
{
if (handler == null)
{
throw new ArgumentNullException(nameof(handler));
}
_reference = new WeakReference(handler);
Filter = filter;
}
/// <summary>
/// Subscribe to change notification with the specified <paramref name="subscriber"/> and collection namespace <paramref name="filter"/>.
/// </summary>
/// <param name="subscriber">The change notification subscriber.</param>
/// <param name="filter">The MongoDB collection namespace wildcard filter.</param>
/// <returns>The subscription instance.</returns>
/// <exception cref="ArgumentNullException"><paramref name="subscriber"/> is <see langword="null" />.</exception>
public ISubscription Subscribe(IHandleChange subscriber, string filter = null)
{
if (subscriber == null)
{
throw new ArgumentNullException(nameof(subscriber));
}
var subscription = new Subscription(subscriber, filter);
lock (_subscribers)
_subscribers.Add(subscription);
return(subscription);
}
