Message modeling is a way of predefining the message formats that are used by your applications.
When you have modeled your messages, WebSphere® Message Broker can use your message models to automatically parse and write your message formats.
When you model messages, you need to understand the following concepts:
A message set project is a specialized project (container) in which you create and maintain all the resources that are associated with exactly one message set.
A message set is a logical grouping of your messages and the objects that comprise them (elements, types, groups). A message set contains the following files:
The message set file provides message model information that is common to all the messages in the message set. You can create this information using the message set editor.
When you have created a message set, you typically import application message formats described by XML DTD, XML Schema, WSDL files, C structures, or COBOL structures, creating and populating message definition files. You can then edit the logical structure of your messages, and create and edit physical formats that describe the precise appearance of your message bit stream during transmission, using the message definition editor. Alternatively, you can create an empty message definition file and create your messages using just the editor.
When your message definition files are complete, you can then generate the message set in a form that can be used by a broker, parser, or application. This might be in one of the following forms:
Messages can be optionally grouped into message categories, both for convenience and to aid the generation of WSDL. You can add messages to message categories using the message category editor.
Each time you save a message set file, message definition file, or message category file, the content is validated to ensure that the message model that you are creating follows certain rules. There are rules for both the logical structure and the physical formats. This 'model validation' ensures the integrity of your model, but does not necessarily prevent you from saving a message model file that is not valid.
WebSphere Message Broker supplies a range of parsers to parse and write message formats. Each parser is suited to a particular class of messages (for example, fixed-length binary, delimited text, or XML) known as a message domain. When you create a message set, you specify which domains the message set supports. This determines which parsers can be used when you parse and write messages that are defined within that message set.