On Applying Design Pattern Approach to Reengineering COBOL Programs

The Design Patterns (DP) approach is one of the mod-ern techniques in the area of Software Engineering. It has been introduced to facilitate and make more effec-tive the process of design and implementation of soft-ware - especially within the object-oriented paradigm (OOP). As usual, each technique that has proven useful for design and development of software is applied, sooner or later, in some other related activities as quali-ty assurance, maintenance, etc. DP approach is actively used in reengineering of existing software systems, too. Unfortunately, when a system is written in an old fash-ioned language like COBOL (in case of the so called legacy system), which is too far away from the OO paradigm, the use of DP is not the most appropriate solution. Business Rules (BR) approach is another technique introduced for the same reason, which is not so closely related to OOP and seems to be more con-venient for reengineering of legacy systems, written in COBOL. The theory and practice of business logic ex-traction in form of BR and using them for improving the design of the legacy system are still under devel-opment. This paper is an attempt to adapt some ideas from DP approach in order to facilitate the process of business logic extraction from programs, written in COBOL.