Converting Legacy Add-in VBA to Smart View Add-in VBA

If you attended my session at ODTUG Kaleidoscope '10 you found out that if you want to convert legacy (classic) add-in VBA solutions to Smart View that there will be some work.  In the session I broke the conversion process into 3 steps; Evaluate, Redesign, and Rewrite.

Evaluate :

• Are there new Smart View features that user want or need to leverage?
• Maybe the custom code has been replaced with a standard Smart View feature.
• Does my current VBA application use the Essbase Visual Basic API? 
• If yes conversion will take longer or may not be possible.
• Are there calls I am making that are deprecated or no longer valid with Smart View?   For Example:
• EssVGetHctxFromSheet
• EssVGetDataPoint
• EssMenuLock
• Perform a code review and understand the scope of the changes you will need to make.
• This is key, make sure you treat the conversion like a ‘real’ development effort!
• Determine if the application can be done with Smart View.
• There will be some cases where conversion is not possible; YET.  This will likely be the case for solutions that heavily leverage the VB API for Essbase.
• Does it make sense to convert.
• What is the size of the applications user base and how long will it be in service.  Maybe the conversion effort is just not worth it and another solution will be better.
• Is there another application that will do the job?
• Maybe your organization has outgrown planning in Spreadsheet and looking at a the Planning product might be a good idea.

Answering these questions and reviewing these points will help you determine when to convert and how large the conversion effort will be.

Redesign:

• Consider what Smart View features can be used to redesign the application.   There maybe new features that will influence how your application works.  For Example:
• POV Toolbar
• Reporting Objects
• Smart Slices
• Understanding the improved Smart View architecture may also guide the redesign.
• TCP/IP vs HTTP(s)
• New Connectivity Model (providers and connections)
• Single Sign On (SSO)

All of these items and more will likely make so that a redesign to some degree is needed and wanted.

Rewtrite:

This is the one that most people hate to hear about.  You cannot do a find and replace and make this work!

• Be sure to back up all your code.
• Do not rewrite on the fly in the project files.
• Use some kind of source control if possible.
• Treat this like a new project and do not roll it out before it is ready.
• Run a test and beta cycle to make sure all the bugs are flushed out prior to releasing your custom application.
• Get a partner involved if you do not have the skill sets in house.

During the session I demo’ed a conversion utility that will assist during the Evaluate stage of this process and it is going to be posted on OTN shortly so be on the look out.  I will be sure to do a blog post when the utility is available.