map a domain to a language, the language to a define 'linked list' functionality in theīase class and implement 'domain' functionality in derived classes a Decorator contains a single base Component, whichĬould be a derived ConcreteComponent or another derived DecoratorĬhain of Responsibility. derived Composites contain one or more base Components,Įach of which could be a derived Compositeĭecorator. the 'model' broadcasts to many possible 'views', andĬomposite. the wrapper models 'abstraction' and the wrappee models Object, and that state object can set the 'next' state objectīridge. the FiniteStateMachine delegates to the 'current' state Įach builder corresponds to a different representation or target the 'reader' delegates to its configured 'builder'. 'double dispatch'Ĭategory: a wrapper wraps an inheritance hierarchyīuilder. define 'accept' method in first inheritance hierarchy,ĭefine 'visit' methods in second hierarchy. define 'createInstance' placeholder in the baseĬlass, each derived class calls the 'new' operator and returns an instance of define algorithm interface in a base class andįactory Method. Up-Down symbol = inheritance hierarchy (promote interface to a base class andīury implementation alternatives in derived classes) wrap an object with a surrogate object that provides wrap a complicated subsystem with an object that provides Interface with an object that supports the desired interfaceįacade. wrap a legacy object that provides an incompatible Left-Right symbol = wrapper/wrappee or delegation or 'has a'Īdapter. Java's new Considered Harmful - Singleton, Flyweight, Factory Method, Abstractįile system (Composite, Proxy, Chain, Iterator,įile system (7 previous patterns, Decorator).Mediator + Observer = Event Notifier (article) Composite, Builder, Iterator, Memento, Visitor demo.

State, Template Method demo (rubber banding).Of indirection to make 2 incompatible objects compatible. Before-and-After refactoring examples.ĭesign Pattern: identify a popular design strategy and document the Dozens of 1-page examples in C++ and Java.

Software wrapper design