/// <summary>
/// Creates an instance of the <see cref="IMessenger"/> class by using the
/// factory class that was defined in the specified configuration node.
/// </summary>
/// <param name="provider">A <see cref="MessengerProviderNode"/> object
/// containing informations that will be used to create the designated
/// type.</param>
/// <returns>A reference to the newly created object.</returns>
/// <exception cref="ArgumentNullException"><paramref name="provider"/>
/// is null.</exception>
/// <exception cref="ProviderException">A valid instance of the factory
/// could not be created -or - a exception was throwed by the factory.
/// </exception>
/// <remarks>
/// <para>
/// If the factory could not be instantiated or if it throws an exception
/// it won't be propagated to the caller. This method packs the exception
/// into a <see cref="ProviderException"/> and throw it.
/// </para>
/// </remarks>
public static IMessenger CreateInstance(MessengerProviderNode provider)
{
if (provider == null)
{
throw new ArgumentNullException("provider");
}
IMessengerFactory factory;
Type type = ProviderHelper.GetTypeFromProviderNode(provider);
if (type == null)
{
throw new ProviderException(string.Format(
StringResources.Type_CreateInstanceOf, "IMessengerFactory"));
}
try {
factory = Activator.CreateInstance(type) as IMessengerFactory;
if (factory == null)
{
throw new ProviderException(string.Format(
StringResources.Type_CreateInstanceOf, "IMessengerFactory"));
}
IMessenger messenger =
factory.CreateMessenger(provider.Name, provider.Options);
// Sanitu check for nulls. By default messenger factories should not
// return nulls, but we can trust on others code.
if (messenger == null)
{
throw new ProviderException(string.Format(
StringResources.Type_CreateInstanceOf, "IMessengerFactory"));
}
return(messenger);
} catch (Exception e) {
// pack the throwed exception and rethrow it.
throw new ProviderException(string.Format(
StringResources.Type_CreateInstanceOf, "IMessenger"), e);
}
}
