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

13 On Patterns versus Pattern Languages

The leader has to be practical and a realist,yet must talk the language of the visionary and the idealist.

Eric Hoffer, American social writer

This chapter compares and contrasts stand-alone patterns and pattern languages. Based on our explorations of both concepts, we summarize their commonalities and differences, and conclude that we have learnt valuable lessons of practice and theory from both concepts and their expression.

13.1 Patterns and Pattern Languages: Similarities

There are several questions that often arise when talking about patterns and pattern languages: in what ways are the two ideas similar? And in what ways do they differ? The answers to these questions help us to understand and appreciate the roles that each play in the pattern concept.

Common Core Properties

Comparing our exploration of patterns with that of pattern languages reveals that ‘good’ and whole patterns and pattern languages share almost all of their core properties, including their documented forms. In particular:

• Each defines a process and a thing. For example, in a design pattern the ‘thing’ is a particular design outline or code detail for a specific problem. For design-centric pattern languages, the ‘thing’ is the design or implementation of an entire system or a system aspect from a specific application or technical domain. For an organizational pattern, the ‘thing’ is a specific workflow or part of an organization. For an organizational pattern language, ...