1. A message processing system including: a set of selectable parsers, each selectable parser being adapted for analyzing a respective set of message data formats and being selectable in response to identifying a message data format within the respective set; a process for invoking, by a data processing apparatus in the message processing system, a parser from the set, wherein at least one of said selectable parsers: parses a first component of a message having a message data format within the respective set; identifies the data format of a second component of the message; responsive to said identification, selects another one of said set of parsers and for invoking the selected parser to parse the second message component; and includes a repository of message format templates, each template representing the field structure of a particular format of message component, wherein said at least one parser is adapted to parse the first component and then to read a format field of a second component of the message to identify the data format of the second component, and wherein invoking the selected parser to parse the second component includes providing to the selected parser an identification of the message format template corresponding to the identified format.