Chapter08设计工程

1、1 2 3 4 Spec modeling 5 6 7 8 9 10 door implemented as a data structure manufacturer model number type swing direction inserts lights type number weight opening mechanism 11 open implemented with a knowledge of the object that is associated with enter details of enter algorithm 12 13 open walk to do

2、or; reach for knob; open door; walk through; close door. repeat until door opens turn knob clockwise; if knob doesnt turn, then take key out; find correct key; insert in lock; endif pull/push door move out of way; end repeat 14 15 16 17 18 19 20 easier to build, easier to change, easier to fix . 21

3、22 成本成本/ /模块模块 接口成本接口成本 Region of minimum cost / 模块数目模块数目 开发成本开发成本 M 23 24 25 MODULE Whats inside? How big is it? 26 COHESION - the degree to which a module performs one and only one function. COUPLING - the degree to which a module is connected to other modules in the system. 27 28 29 30 A Flag？ Fl

4、ag B f1f2 fn 控制耦合 31 AB Common公共数据区 AB Common公共数据区 松散的公共 耦合 紧密的公共 耦合 32 A B 进入另一模块内部 多入口模块 AB 模块代码重叠 Entry 1 Entry n 内容耦合 33 Global:A1 A2 A3 Variables: V1 V2 Change V1 to 0 Increment V1 V1 =V2+A1 Component XComponent YComponent Z Common data area and variable names 34 AB CD X 传递 数据 传递数 据结构 A，B为非直接耦合

5、 A，C为数据耦合 A，D为标记耦合 35 36 37 38 建立方程组系数矩阵 高斯消去法 回 代 示例 39 A STROE rec ( ) to N READ X File ADD 1 to z B STROE rec ( ) to N READ X File ADD 1 to z M STROE rec ( ) to N READ X File ADD 1 to z AB 偶然性内聚 40 A 判定参 数 参数 B f1f2 fn 模块B属于逻辑内聚 41 读文件 打印检 验结果 计算A 计算B 合并 新 文 件 文件 加工记录模块 通讯内聚 42 43 44 45 46 47 Spe

6、cification Source Code Design Forward Engineering Restructuring Redocumenting Reverse Engineering Reengineering Bohner 1990 dirty source code Restructure code extract abstractions refine & simplify clean source code initial specification final specification processing interface database 55 56 启发式规则是一种经验规律，启发式规则是一种经验规律， 对改进设计和提高软件质量具对改进设计和提高软件质量具 有重要的参考价值，但不要过有重要的参考价值，但不要过 分拘泥于这些规则分拘泥于这些规则 57 58 59 60 61 A BCDF GH KJI E 62 63 G G中的判定影响中的判定影响C C TOPTOP中的判定影响太远中的判定影响太远 64 65 66 67 68 69 70 71 72 SensorManagementSensor 73 SensorManagement Personal Computer Control Panel Security Security