ABSTRACT
Chapter 4 discussed patterns and tactics that can be used for creating an architecture of a system. We can take the list of architectural drivers for a given system and, for each driver, consider patterns or tactics that might address design concerns inherent in that driver. When the first driver on the list is considered, it will yield a structure (based on patterns or tactics selected) that will satisfy its design concerns. We can then move to the next driver on the list and examine if the structure resulting from satisfying the first driver also satisfies the design concerns of this driver. If it does, we can move on to the next driver, but if it does not, we must examine how we refine this structure (using additional patterns or tactics) to satisfy these concerns. We continue to repeat this process until the structure has been sufficiently refined to yield a final architecture that addresses all design concerns associated with all the drivers on the list. It should be noted that design concerns
are seldom completely addressed. Conflicting design concerns have to be traded against each other and reasonable compromise has to be reached. Hence, creating an architecture is about finding the middle ground by trading off competing and conflicting objectives.
