Template method pattern
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Intent: Define the skeleton of an algorithm in an operation, deferring some steps to subclasses. TemplateMethod lets subclasses redefine certain steps of an algorithm without changing the algorithms's structure. DesignPatterns, p. 325
http://rampages.onramp.net/~huston/dp/templateMethod.html
http://wiki.cs.uiuc.edu/PatternStories/TemplateMethodPattern
CategoryPattern | CategoryBehavioralPatterns