/// <summary>
/// This method checks if the command line has a valid length and a valid editor command in the first place.
/// </summary>
/// <param name="commandLine">The command line the user has written.</param>
/// <returns>
/// A full instanced command if the command line is valid or null if the command line is not valid.
/// </returns>
/// <exception cref="ArgumentNullException">
/// If commandLine is null or whitespace.
/// </exception>
public IEditorCommand Parse(string commandLine)
{
if (string.IsNullOrWhiteSpace(commandLine))
{
throw new ArgumentNullException();
}
string[] possibleCommands = commandLine.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
string editorCommand = possibleCommands[0].ToLower();
if (possibleCommands.Length > 4)
{
return(null);
}
else
{
switch (editorCommand)
{
case "add":
return(AddCommand.Parse(commandLine));
case "clear":
return(ClearCommand.Parse(commandLine));
case "insert":
return(InsertCommand.Parse(commandLine));
case "remove":
return(RemoveCommand.Parse(commandLine));
case "new":
return(NewCommand.Parse(commandLine));
case "run":
return(RunCommand.Parse(commandLine));
default:
return(null);
}
}
}