5.3 When to use the aXes Terminal Server Activities
In general, preferred LANSA Composer techniques for integrating with an existing IBM i application would include direct integration with:
- the application's database using Transformation Maps, and/or
- application program interfaces provided by the application using CALL_3GL, CALL_FUNCTION or CALL_JAVA activities or by creating custom activities.
Using such techniques will generally provide the most resilient and the best performing solution as well as being the easiest to maintain.
However, there can be instances where the above types of integration are not possible. For example when the necessary domain knowledge is NOT available or it is NOT technically feasible to:
- directly access the application database using transformation maps.
- use application program interfaces or such interfaces do not exist.
In these circumstances, being able to drive the 5250 screens may provide a level of integration with the application that may not otherwise be possible. Where this is the case, LANSA Composer's aXes terminal server activities can provide the solution.
A solution employing LANSA Composer's aXes terminal server activities will be most suitable where:
- alternative (preferred) forms of integration (as above) have been ruled out;
- the solution will require a relatively limited amount of 5250 interaction
- the solution will involve a manageable set of individual data items (sent to or received from the 5250 screens) that can be transferred to and from the LANSA Composer processing sequence variable pool without excessive performance or maintenance burden;
- the performance of the 5250 interactions in relation to the overall solution is not critical.
If you are unsure whether your solution will meet those criteria, there are alternative techniques you may wish to consider. These can still provide the benefits of both the aXes terminal server and of LANSA Composer, but provide reduced complexity. They do, however, mean that program code must be written.
For example, you could code custom activities or functions that use LANSA Integrator's aXesTerminalService directly to complete all the 5250 interaction associated with a known transaction in one step. Then the custom activity or function can be included in the LANSA Composer process along with associated transport, transformation and other activities and directives as required.
Alternatively, you could code directly to an aXes API for an even more efficient and direct solution.