Automation vs. Quality in Application Modernization

by Mike Oara
November 1, 2007



Intermediate Models

What types of models capture legacy application functionality to create a new modern implementation? There are many types of models, supported by various tools, but let’s focus on three that have widespread acceptance and support standards:

Unified Modeling Language (UML): In this case, the analyst may extract information in the form of use cases, activity and sequence diagrams, or class diagrams, etc. Most commercially available software tools that support UML also offer a forward-engineering capacity that facilitates high-quality code.

Business rules: Specialized software tools can help locate the business rules of an application; these rules govern the minute computations, decisions or validations in an application and express the specifics of how the business decides to run certain operations.

Data models: Usually, data models can be extracted from data definitions in the application. If the source application and new application are based on the same type of database technology, few model changes are needed. However, in other cases, some model derivation may be necessary. One such example is the transition from a hierarchical to a relational model.

With these three types of models, it’s theoretically possible to express most functional aspects of an application, simultaneously leaving aside the incidental technical implementation details. This presents a great advantage, resulting in a clean design and the freedom to choose the best technical implementation of the transformed application, in view of the organization’s existing software, skills, and preferences. Another advantage is that the model extraction and refinement may be executed at any time before the new implementation is built. The IT organization would immediately benefit from clear documentation of the existing application; actual reimplementation work may start when the time is right and all major decisions regarding architecture are made.

Conclusions

Application modernization projects may greatly benefit from automation, as long as both the possibilities and obstacles are well-known in advance. There’s no unique technology or methodology to address all issues at once, but there’s a large spectrum of partial solutions. Choosing the right portfolio of such solutions is the key to a successful modernization project executed on time and with high-quality results.

Being fully aware of both the benefits and the pitfalls of various automation methods, a team charged with executing an application modernization may choose a portfolio of such solutions that best fit its goals and constraints. For example, data transformation could proceed with a common conversion solution, User Interface (UI) transformation may proceed on a code transformation path, and procedural code may be used in a model-based transformation.