Status: IN
Observer's push-vs-pull notification models and Strategy's two data-passing approaches instantiate an isomorphic design tension: eagerly providing all data (simpler protocol but couples the receiver to unused information) versus letting the receiver pull what it needs (more flexible but requires a back-reference to the data source).
Both patterns independently discover the same push-vs-pull data flow tradeoff
Depends on (SL): gof-observer-push-vs-pull-models, gof-strategy-data-passing-two-approaches