Hi Kent! Head First Object Oriented Analysis & Design some times say that design patterns are applied at the implementation phase of software development. Head First Design Patterns say that design patterns can be applied at any phase(as I understood: analysis, design, implementation ). I agree, partially, with both. In my humble opinion, some times it is difficult to decide when. Does your book help us clarify moment that we can implent patterns?
Finding the right time to make a decision is as important a skill as knowing how to make the decision. Too much too early and you delay feedback and give yourself a design you have to work around. Too little too late and you start to sink in complexity. Implementation Patterns doesn't address the timing of using patterns thoroughly. The patterns are all intended to be used at coding time. However, I am sure the book contains some of my bias towards deferring decisions until I am certain. I use this strategy whether I am working with architectural, analysis, design, implementation, or optimization decisions.
Kent Beck Three Rivers Institute
Author of <a href="http://www.amazon.com/exec/obidos/ASIN/0596007434/ref=jranch-20" target="_blank" rel="nofollow">JUnit Pocket Guide</a>
subject: Implementation Patterns: When to apply patterns?