Summary

In this chapter, I described what design patterns are. Christopher Alexander says “patterns are solutions to a problem in a context.” They are more than a kind of template to solve one's problems. They are a way of describing the motivations by including both what we want to have happen along with the problems that are plaguing us.

I looked at reasons for studying design patterns. Such study helps to

• Reuse existing, high-quality solutions to commonly recurring problems.

• Establish common terminology to improve communications within teams.

• Shift the level of thinking to a higher perspective.

• Decide whether I have the right design, not just one that works.

• Improve individual learning and team learning.

• Improve the modifiability of code.

• Facilitate adoption of improved design alternatives, even when patterns are not used explicitly.

• Discover alternatives to large inheritance hierarchies.