Structural Patterns Class patterns – inheritance Object patterns – composition - you can change the composed class at run-time

class UsefulClass useful_operation() Class NicksClass UsefulClass myUsefulClass; nicks_operation() { myUsefulClass.useful_operation() }

OtherClass Request()

Bridge Abstraction – the set of operations a class or class hierarchy must support Implementation – Different ways of performing those operations

DataImp UpdateData SQLupdate PickleUpdate changeGrade(name…) Send SQL update cmn To database changeGrade(name…) { Read in data, change it, Write to file

? ? DataImp UpdateData SQLupdate PickleUpdate changeGrade(name…) Send SQL update cmn To database changeGrade(name…) { Read in data, change it, Write to file