/// <summary>
/// Appends only a message when the predicate function returns true.
/// For recursion: Recursion will only occur when the predicate returns true.
/// If no predicate is specified, a default predicate that returns true unless the selector returns default(TMessageType) is used
/// </summary>
/// <typeparam name="TMessageType">The message type
/// </typeparam>
/// <param name="builder">The append decorator builder</param>
/// <param name="predicate">The predicate</param>
/// <returns>A builder</returns>
public static IAppendManyDecoratorBuilder <TMessageType> Where <TMessageType>(this IAppendManyDecoratorBuilder <TMessageType> builder, Func <TMessageType, bool> predicate)
{
if (predicate == null)
{
throw new ArgumentNullException(nameof(predicate));
}
return(builder.Where((message, token) => Task.FromResult(predicate(message))));
}
/// <summary>
/// The function used to select the message to append
/// </summary>
/// <typeparam name="TMessageType">The message type
/// </typeparam>
/// <param name="builder">
/// The append decorator builder
/// </param>
/// <param name="messageSelector">
/// The function used to select the message to append
/// </param>
/// <returns>
/// A builder
/// </returns>
public static IAppendManyDecoratorBuilder <TMessageType> Select <TMessageType>(this IAppendManyDecoratorBuilder <TMessageType> builder, Func <TMessageType, IEnumerable <TMessageType> > messageSelector)
{
if (messageSelector == null)
{
throw new ArgumentNullException(nameof(messageSelector));
}
return(builder.Select((message, token) => Task.FromResult(messageSelector(message))));
}