Pattern Oriented Software Architecture Volume 5: On Patterns and Pattern Languages

7 Pattern Sequences

I cordially dislike allegory in all its manifestations, andalways have done so since I grew old and wary enoughto detect its presence. I much prefer history, true orfeigned, with its varied applicability to the thought andexperience of readers. I think that many confuse‘applicability’ with ‘allegory’; but the one resides in thefreedom of the reader, and the other in the purposeddomination of the author.

J.R.R. Tolkien

This chapter builds on the pattern relationships discussed thus far in this part of the book. Pattern stories offer a presentation form that describes how patterns have been (or might be) applied concretely to construct a particular system, implement a specified feature, or transform a given situation. Pattern sequences generalize this narrative into something more fundamental, distilling out the actual sequence of patterns applied so that the same sequence can be considered elsewhere. The discussion of pattern sequences allows us to revisit the question of context once again.

7.1 Patterns Tell Software Engineering Success Stories

There is no single privileged view of what a software system is or how it was developed. Each perspective highlights one aspect that may not be visible from another point of view and communicates a slightly different message. For example:

• A code-centric view emphasizes detail and precision. Although modern programming languages have support for expressing modular structure, many of the relationships present in the ...