Software architecture is the art of drawing lines that I call boundaries. Those boundaries separate software elements from one another, and restrict those on one side from knowing about those on the other. Some of those lines are drawn very early in a project’s life—even before any code is written. Others are drawn much later. Those that are drawn early are drawn for the purposes of deferring decisions for as long as possible, and of keeping those decisions from polluting the core business logic.

Recall that the goal of an architect is to minimize the human resources required to build and maintain the required system. ...

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