Round-trip engineering with the Two-Tier Programming Toolkit

A major impediment to the long-term quality of large and complex programs is inconsistency between design and implementation. Conflicts between intent and execution are common because detecting them is laborious, error-prone, and poorly supported, and because the costs of continuously maintaining design documents outweigh immediate gains. A growing inconsistency between design and implementation results in software that is unpredictable and poorly understood. Round-trip engineering tools support an iterative process of detecting conflicts and resolving them by changing either the design or the implementation. We describe a Toolkit which supports a round-trip engineering of native Java programs without interfering with any existing practices, tools, or development environments, thereby posing a minimal barrier on adoption. The Toolkit includes a user-guided software visualization and design recovery tool, which generates Codecharts from source code. A “round-trip” process is possible because Codecharts visualizing source code can be edited to reflect the intended design, and the Verifier can detect conflicts between the intended and as-implemented design. We demonstrate each stage in this process, showing how the Toolkit effectively helps to close the gap between design and implementation, recreate design documentation, and maintaining consistency between intent and execution.