Browse Prior Art Database

Message Data Conversion

IP.com Disclosure Number: IPCOM000115117D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 115K

Publishing Venue

IBM

Related People

Halliwell, H: AUTHOR

Abstract

Problems can arise in message queue managers because of differences in the representation of application message data. Typically, a message queue manager will provide conversion of the fixed auxiliary information when a message is passed (asynchronously) between disparate systems; there is no conversion of the application message data itself.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 46% of the total text.

Message Data Conversion

      Problems can arise in message queue managers because of
differences in the representation of application message data.
Typically, a message queue manager will provide conversion of the
fixed auxiliary information when a message is passed (asynchronously)
between disparate systems; there is no conversion of the application
message data itself.

      The differences in the data representation of the messages can
occur because the communicating applications are operating on
machines with different architectures, or because they use character
strings in different code pages or CCSIDs.  The following
considerations have to be addressed:
  o  The message data is to be converted only when necessary.  For
      example, no conversion is needed when the sending and receiving
      applications handle the message using the same data
      representation.
  o  The above consideration is also to apply in a "multi-hop"
message
      transfer - where the message passes through one or more
      intermediate queue managers before it reaches its destination
      queue and the server application.  There is to be at most one
      message conversion.
  o  Some compilers may generate code for different data
      representations on a single platform.  Hence the need for data
      conversion that can apply to messages between local
applications
      as well as those sent across a network.
  o  The method needs to be able to work where the application runs
on
      a client workstation, and executes the messages calls on a
queue
      manager server.
  o  A queue manager provided with a message conversion capability
has
      to exchange messages with other queue managers in the family
      which do not necessarily have that capability.

      The method described below was developed for the IBM* MQSeries*
queue manager products.  These provide the following facilities:
  o  When an application PUTs a message, it sends auxiliary data as
      well.  This "header" contains information that describes the
      message.  An application that GETs the message receives the
      descriptive header too.
  o  Message headers are always converted by MQSeries queue managers.
       They have a fixed structure, so the queue managers know
        what type of conversion is required.  The requirements of the
        queue managers can lead to extra conversion being performed
when
        a message passed through an intermediate system.
  o  Among the contents of the header are the "Representation" and
      "Format" of the message it describes.  The "Format" is a name
for
      the shape of the application data.

      In this context the addition of the following features deals
effectively with the problem discussed above.
  1.  The interface to GET a message includes the requi...