Reuse, Reface or Rewrite?
In the RAMP context the decisions about Reusing (5250 screens) versus Refacing (using Screen Wrappers) versus Rewriting (new VL component) are complex.
Next time you hear someone say “I could rewrite that in a week”, you need to ensure that they have accounted for:
1. Time to discover and understand all the existing functionality and interfaces.
2. Time to redesign with a modernized UI.
3. Time to code and unit test (this step might actually be a week, as stated).
4. Time to (re)test all the existing functionality and interfaces.
When you hear people say “I can rewrite that in a week” you will often mentally double or triple that to allow for testing, etc. Any x2 or x3 factor you apply might actually need to be x10 or more in rewrite situations (ie: step 3 may be less that 10% of the whole job).
The chum/wrapper solution is useful because it radically reduces the time required to complete steps 1 and 4.
Also, if you are looking at using some sort of template/wizard/code generation techniques, remember that you are only likely to speed up step 3.
ie: If step 3 is only 10% of the job, and you do it twice as fast, you will only have improved the whole project by 5%, not by 50%.