1. 1 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Supplementary Slides for Software Engineering: A Practitioner's Approach, 5/e Supplementary Slides for Software Engineering: A Practitioner's Approach, 5/e copyright © 1996, 2001 R.S. Pressman & Associates, Inc. For University Use Only May be reproduced ONLY for student use at the university level when used in conjunction with Software Engineering: A Practitioner's Approach. Any other reproduction or use is expressly prohibited. This presentation, slides, or hardcopy may NOT be used for short courses, industry seminars, or consulting purposes.

2. 2 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Slide 26 Chapter 24 Technical Metrics for Object-Oriented Systems

3. 3 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Distinguishing Characteristics  Localization—the way in which information is concentrated in a program  Encapsulation—the packaging of data and processing  Information hiding—the way in which information about operational details is hidden by a secure interface  Inheritance—the manner in which the responsibilities of one class are propagated to another  Abstraction—the mechanism that allows a design to focus on essential details Berard [BER95] argues that the following characteristics require that special OO metrics be developed:

4. 4 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Class-Oriented Metrics  weighted methods per class (WMC)  WMC =  c i for I = 1 to n  Where c i is complexity of method i  Inheritance may complicate the counting  depth of the inheritance tree (DIT)  number of children (NOC)  coupling between object classes (CBO)  response for a class (RFC)  Set of methods that are potentially executed in response to a message  lack of cohesion in methods (LCOM) Proposed by Chidamber and Kemerer (CK Metrics):

5. 5 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Class-Oriented Metrics  class size (CS)  Total number of operations  The number of attributes  too much responsibility would reduce reusability  number of operations overridden by a subclass (NOO)  number of operations added by a subclass (NOA)  specialization index (SI)  Specialization achieved by adding or deleting operations by overriding  SI = (NOO * level)/M level is the level in the class hierarchy, M is number of methods  The higher the SI, the more likely do not conform to the superclass abstraction Proposed by Lorenz and Kidd [LOR94]:

6. 6 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Class-Oriented Metrics  Method inheritance factor (MIF)  The degree of the use of inheritance  Coupling factor (CF)  Connections between elements of the OO design  Polymorphism factor (PF)  Indirect measure of the amount of dynamic binding in a system The MOOD Metrics Suite

7. 7 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Operation-Oriented Metrics  average operation size (OS avg )  LOC or  Number of messages sent by operation  operation complexity (OC)  Use complexity metrics  average number of parameters per operation (NP avg )  Affect the complexity of collaboration Proposed by Lorenz and Kidd [LOR94]:

8. 8 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Testability Metrics  encapsulation related  lack of cohesion in methods (LCOM)  percent public and protected (PAP)  public access to data members (PAD)  inheritance related  number of root classes (NOR)  fan in (FIN)  Indication of multiple inheritance  number of children (NOC) and depth of inheritance tree (DIT) Proposed by Binder [BIN94]:

9. 9 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 OO Project Metrics  number of scenario scripts (NSS)  Number of scenario script/use case is proportional to the number of classes  number of key classes (NKC)  Low probability for reuse  substantial work  number of subsystems (NSUB)  Provides insight into resource allocation, scheduling & integration effort Proposed by Lorenz and Kidd [LOR94]: