简介 Define an object that encapsulates how a set of objects interact. Med...

简介 Represent an operation to be performed on the elements of an object s...

简介 Allow an object to alter its behavior when its internal state changes...

简介 Without violating encapsulation, capture and externalize an object's ...

简介 Encapsulate a request as an object,thereby letting you parameterize c...

简介 Advoid coupling the sender of a reuest to its receiver by giving more...

简介 Provide a way to access the elements of an aggregate object sequenti...

简介 观察者模式（Observer Pattern），又叫 发布-订阅（Publish/Subscribe）模式、模型-视图（Model/Vie...