7.2. Background on This Exercise: Building the System

Interestingly, I’ve found that when designing modular software, it’s tough to identify the modules early in the life cycle. Instead, shifts typically occur, and as things unfold, the modules become more apparent as development progresses. With a SOLID object-oriented design, it’ll make it much easier to move things around and create new modules. So to start, although the system is small, I favor coarser-grained and heavier-weight modules.

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SOLID principles, 319

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As specific needs emerge, we’ll break larger modules out into a bunch of finer-grained and lighter-weight modules that address specific functional and nonfunctional needs. Remember that the material in the first six chapters describes the essence of my motivation here. If you skipped right to the code and haven’t read any of the previous material, I encourage you to check it out now. (Of course, you can choose to wait and see what I’m talking about, because we’ll experience this phenomenon as we move through this chapter’s exercise. I hope that will peak your curiosity and you’ll review the material in the previous chapters.)