public void Register(IPostalUser postalUser)
{
if (postalUser == null)
{
throw new ArgumentNullException(nameof(postalUser));
}
if (!this._usersByPostalCode.ContainsKey(postalUser.PostalCode))
{
this._usersByPostalCode.Add(postalUser.PostalCode, postalUser);
}
}
public void Send(IPostalUser fromPostalUser, string toPostalCode, Parcel parcel)
{
if (fromPostalUser == null)
{
throw new ArgumentNullException(nameof(fromPostalUser));
}
if (this._usersByPostalCode.TryGetValue(toPostalCode, out IPostalUser toPostalUser))
{
toPostalUser.ReceiveParcel(fromPostalUser.PostalCode, parcel);
}
// Make sure the sender is not rejecting parcels, otherwise we may end up with an infinite callback.
else if (!(fromPostalUser is RejectingParcelUser))
{
// Send it back, we couldn't find the recipient
fromPostalUser.ReceiveParcel(toPostalCode, parcel);
}
}
