Design Patterns Java™ Workbook

Comparing Strategy and State

The refactored code consists almost entirely of simple methods in simple classes. This is an advantage in its own right and makes adding new strategies easy. The refactoring relies primarily on the idea of distributing an operation across a related group of classes. In this regard, STRATEGY is identical to STATE. In fact, many developers wonder whether these are really different patterns.

On the one hand, in the real world, strategies (such as recommending a firework) and states (such as a carousel door with a one-touch control button) are clearly different ideas. This real difference leads to different problems in modeling states and strategies. For example, transitions are important when modeling states but usually ...