Automatic Proof of Refinement among Design Patterns using the TLC Model Checker

Design patterns are reuse artifacts meant to improve the quality of software designs as well as the productivity of designers. Patterns (and their relationships) are mostly described in an informal fashion which leads to ambiguity and limits tools support. This has worsened with the growing number of well-established and candidate patterns. This paper discusses how to formally specify the "solution element" of patterns and their relationships using TLA+, the formal specification language of Temporal Logic of Actions (TLA). The paper first classifies and formally defines the most common relationships between patterns. Then, it shows how to automatically proof the existence of a "refines" relationship between patterns using TLC− the TLA+ Model Checker.