abstract_factory (1) adapter (1) algorithm (1) architecture (1) book (11) books (1) codeownership (1) collaborative filtering (1) composite (1) culture (1) decorator (1) design pattern (1) design_pattern (11) facade (1) factory_method (1) geohash (1) gof (11) observer (1) oop (1) recommendation (1) singleton (1) strategy (1) template_method (1) theory (14) translate (3) web (2)