软件架构复习笔记6

1、 HYPERLINK http:/blog.sheimi.me/note/2012/06/20/software-architecture-review-7.html 软件架构复习笔记(6) - 模块化20 Jun 2012At NJUPinciplesGlobal Vriables Consider HarmfulTo be explicitDo not RepeatProgramming to InterfaceGet Specified, Design by Contract(Suffered Interface: Specified vs Required Interface: Use

2、d)CouplingContent CouplingCommon Coupling: Global ValueModification Coupling: Do not RepeatControl Coupling: pass data and control elementsStamp Coupling: pass data more than necessaryData Coupling: passing dataReduce couplingEncapsulation reduce coupling: Data encapsulationSubdividing the potential

3、 shared elements into groupsLimiting each group access to the smallest possible subset of modulesConnections that address or refer to a module as a whole by its name yield lower coupling than connections referring to the internal elements of another module(Programming to interface)CohesionCoincident

4、al: No BindingLogical: Binding by logical similarityTemporal: Binding by logical similarity + timeCommunicational: Binding by the same dataSequential: Binding by the same problemFunctional: Binding by the same goalinformationOO CouplingComponent couplingInheritance CouplingMessage passing coupling(k

5、eep it low)Data abstraction coupling(keep it low)Module coupling(keep it low)Component couplingWhole variable: Aggregation(Global)Parameter: Method parameter(Local)Creator: Creator in some mehods localHidden: Given by another object (worst:implicit)The law of demeterYou can play with yourselfYou can

6、 play with your own toy but you cant take them apertYou can play with toys that were given to youYou can play with toys youve made yourselfInheritance CouplingModification (Implicit, Harm)Refinement (Necessary)Extension (LSP)OO CohesionProcedural CohesionSingle Abstraction Cohesion (to achieve a common purpose)Cohesion of AttributeSeparableMultifacetedNon-delegatedConcealedModel: informational strengthThe best objectsInformation cohesion (maintain consi