1. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 1 Software Engineering: A Practitioner’s Approach, 6/e Chapter 8 Analysis Modeling Software Engineering: A Practitioner’s Approach, 6/e Chapter 8 Analysis Modeling copyright © 1996, 2001, 2005 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.

2. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 2 Requirements Analysis Requirements analysis Requirements analysis specifies software’s operational characteristics specifies software’s operational characteristics indicates software's interface with other system elements indicates software's interface with other system elements establishes constraints that software must meet establishes constraints that software must meet

3. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 3 Requirements analysis allows the software engineer (called an analyst or modeler in this role) to: Requirements analysis allows the software engineer (called an analyst or modeler in this role) to: elaborate on basic requirements established during earlier requirement engineering tasks elaborate on basic requirements established during earlier requirement engineering tasks build models that depict build models that depict user scenarios, user scenarios, functional activities, functional activities, problem classes and their relationships, problem classes and their relationships, system and class behavior, and system and class behavior, and the flow of data as it is transformed. the flow of data as it is transformed.

4. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 4 A Bridge

5. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 5 Rules of Thumb The model should focus on requirements that are visible within the problem or business domain. The level of abstraction should be relatively high. The model should focus on requirements that are visible within the problem or business domain. The level of abstraction should be relatively high. Each element of the analysis model should add to an overall understanding of software requirements and provide insight into the information domain, function and behavior of the system. Each element of the analysis model should add to an overall understanding of software requirements and provide insight into the information domain, function and behavior of the system. Delay consideration of infrastructure and other non-functional models until design. Delay consideration of infrastructure and other non-functional models until design. Minimize coupling throughout the system. Minimize coupling throughout the system. Be certain that the analysis model provides value to all stakeholders. Be certain that the analysis model provides value to all stakeholders. Keep the model as simple as it can be. Keep the model as simple as it can be.

6. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 6 Domain Analysis Software domain analysis is the identification, analysis, and specification of common requirements from a specific application domain, typically for reuse on multiple projects within that application domain... [Object-oriented domain analysis is] the identification, analysis, and specification of common, reusable capabilities within a specific application domain, in terms of common objects, classes, subassemblies, and frameworks... Donald Firesmith

7. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 7 Domain Analysis Define the domain to be investigated. Define the domain to be investigated. Collect a representative sample of applications in the domain. Collect a representative sample of applications in the domain. Analyze each application in the sample. Analyze each application in the sample. Develop an analysis model for the objects. Develop an analysis model for the objects.

8. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 8 Data Modeling examines data objects independently of processing examines data objects independently of processing focuses attention on the data domain focuses attention on the data domain creates a model at the customer’s level of abstraction creates a model at the customer’s level of abstraction indicates how data objects relate to one another indicates how data objects relate to one another

9. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 9 What is a Data Object? Object —something that is described by a set of attributes (data items) and that will be manipulated within the software (system) eachinstance of an object (e.g., a book) can be identified uniquely (e.g., ISBN #) each plays a necessary role in the system i.e., the system could not function without access to instances of the object each is described by attributes that are themselves data items

10. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 10 Typical Objects external entities (printer, user, sensor) things (e.g, reports, displays, signals) (e.g, reports, displays, signals) occurrences or events (e.g., interrupt, alarm) roles (e.g., manager, engineer, salesperson) organizational units (e.g., division, team) (e.g., division, team) places (e.g., manufacturing floor) (e.g., manufacturing floor) structures (e.g., employee record)

11. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 11 Data Objects and Attributes A data object contains a set of attributes that act as an aspect, quality, characteristic, or descriptor of the object object: automobile attributes: make make model model body type body type price price options code options code

12. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 12 What is a Relationship? relationship —indicates “connectedness”; a "fact" that must be "remembered" by the system and cannot or is not computed or derived mechanically several instances of a relationship can exist several instances of a relationship can exist objects can be related in many different ways objects can be related in many different ways

13. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 13 ERD Notation (0, m) (1, 1) object object relationship 1 2 One common form: (0, m) (1, 1) object 1 object 2 relationship Another common form: attribute

14. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 14 Building an ERD Level 1—model all data objects (entities) and their “connections” to one another Level 1—model all data objects (entities) and their “connections” to one another Level 2—model all entities and relationships Level 2—model all entities and relationships Level 3—model all entities, relationships, and the attributes that provide further depth Level 3—model all entities, relationships, and the attributes that provide further depth

15. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 15 The ERD: An Example (1,1) (1,m) places Customer request for service generates (1,n) (1,1) workorder worktasks materials consistsof lists (1,1) (1,w) (1,1) (1,i) selectedfrom standard task table (1,w) (1,1)

16. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 16 Object-Oriented Concepts Must be understood to apply class-based elements of the analysis model Must be understood to apply class-based elements of the analysis model Key concepts: Key concepts: Classes and objects Classes and objects Attributes and operations Attributes and operations Encapsulation and instantiation Encapsulation and instantiation Inheritance Inheritance

17. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 17 Classes object-oriented thinking begins with the definition of a class, often defined as: object-oriented thinking begins with the definition of a class, often defined as: – template – generalized description – “blueprint”... describing a collection of similar items a metaclass (also called a superclass) establishes a hierarchy of classes a metaclass (also called a superclass) establishes a hierarchy of classes once a class of items is defined, a specific instance of the class can be identified once a class of items is defined, a specific instance of the class can be identified

18. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 18 Building a Class

19. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 19 What is a Class? external entities things occurrences roles organizational units places structures class name attributes: operations:

20. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 20 Encapsulation/Hiding The object encapsulates both data and the logical procedures required to manipulate the data Achieves “information hiding” method # 1 data method # 2 method # 4 method # 5 method # 6 method # 3

21. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 21 Class Hierarchy Chair Table Desk”Chable" instances of Chair PieceOfFurniture (superclass) subclasses of the

22. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 22 Methods (Operations, Services) An executable procedure that is encapsulated in a class and is designed to operate on one or more data attributes that are defined as part of the class. A method is invoked via message passing.

23. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 23 Scenario-Based Modeling “[Use-cases] are simply an aid to defining what exists outside the system (actors) and what should be performed by the system (use-cases).” Ivar Jacobson (1) What should we write about? (2) How much should we write about it? (3) How detailed should we make our description? (4) How should we organize the description?

24. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 24 Use-Cases a scenario that describes a “thread of usage” for a system a scenario that describes a “thread of usage” for a system actors represent roles people or devices play as the system functions actors represent roles people or devices play as the system functions users can play a number of different roles for a given scenario users can play a number of different roles for a given scenario

25. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 25 Developing a Use-Case What are the main tasks or functions that are performed by the actor? What are the main tasks or functions that are performed by the actor? What system information will the the actor acquire, produce or change? What system information will the the actor acquire, produce or change? Will the actor have to inform the system about changes in the external environment? Will the actor have to inform the system about changes in the external environment? What information does the actor desire from the system? What information does the actor desire from the system? Does the actor wish to be informed about unexpected changes? Does the actor wish to be informed about unexpected changes?

26. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 26 Use-Case Diagram

27. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 27 Activity Diagram Supplements the use-case by providing a diagrammatic representation of procedural flow

28. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 28 Swimlane Diagrams Allows the modeler to represent the flow of activities described by the use-case and at the same time indicate which actor (if there are multiple actors involved in a specific use-case) or analysis class has responsibility for the action described by an activity rectangle

29. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 29 Flow-Oriented Modeling Represents how data objects are transformed at they move through the system A data flow diagram (DFD) is the diagrammatic form that is used Considered by many to be an ‘old school’ approach, flow- oriented modeling continues to provide a view of the system that is unique—it should be used to supplement other analysis model elements

30. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 30 The Flow Model Every computer-based system is an information transform.... computerbasedsystem input output

31. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 31 Flow Modeling Notation external entity process data flow data store

32. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 32 External Entity A producer or consumer of data Examples: a person, a device, a sensor Another example: computer-based system Data must always originate somewhere and must always be sent to something

33. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 33 Process A data transformer (changes input to output) Examples: compute taxes, determine area, format report, display graph Data must always be processed in some way to achieve system function

34. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 34 Data Flow Data flows through a system, beginning as input and be transformed into output. computetrianglearea base height area

35. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 35 Data Stores Data is often stored for later use. look-upsensordata sensor # report required sensor #, type, location, age sensor data sensor number type, location, age

36. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 36 Data Flow Diagramming: Guidelines all icons must be labeled with meaningful names all icons must be labeled with meaningful names the DFD evolves through a number of levels of detail the DFD evolves through a number of levels of detail always begin with a context level diagram (also called level 0) always begin with a context level diagram (also called level 0) always show external entities at level 0 always show external entities at level 0 always label data flow arrows always label data flow arrows do not represent procedural logic do not represent procedural logic

37. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 37 Constructing a DFD—I review the data model to isolate data objects and use a grammatical parse to determine “operations” review the data model to isolate data objects and use a grammatical parse to determine “operations” determine external entities (producers and consumers of data) determine external entities (producers and consumers of data) create a level 0 DFD create a level 0 DFD

38. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 38 Level 0 DFD Example user processingrequest videosource NTSC video signal digitalvideoprocessor requestedvideosignal monitor

39. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 39 Constructing a DFD—II write a narrative describing the transform write a narrative describing the transform parse to determine next level transforms parse to determine next level transforms “balance” the flow to maintain data flow continuity “balance” the flow to maintain data flow continuity develop a level 1 DFD develop a level 1 DFD use a 1:5 (approx.) expansion ratio use a 1:5 (approx.) expansion ratio

40. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 40 The Data Flow Hierarchy P a b xy p1 p2 p3 p4 5 a b c d e f g level 0 level 1

41. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 41 Flow Modeling Notes each bubble is refined until it does just one thing each bubble is refined until it does just one thing the expansion ratio decreases as the number of levels increase the expansion ratio decreases as the number of levels increase most systems require between 3 and 7 levels for an adequate flow model most systems require between 3 and 7 levels for an adequate flow model a single data flow item (arrow) may be expanded as levels increase (data dictionary provides information) a single data flow item (arrow) may be expanded as levels increase (data dictionary provides information)

42. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 42 Process Specification (PSPEC) PSPEC narrative pseudocode (PDL) equations tables diagrams and/or charts bubble

43. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 43 Maps into DFDs: A Look Ahead analysis model design model

44. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 44 Control Flow Diagrams Represents “events” and the processes that manage events Represents “events” and the processes that manage events An “event” is a Boolean condition that can be ascertained by: An “event” is a Boolean condition that can be ascertained by: listing all sensors that are "read" by the software. listing all sensors that are "read" by the software. listing all interrupt conditions. listing all interrupt conditions. listing all "switches" that are actuated by an operator. listing all "switches" that are actuated by an operator. listing all data conditions. listing all data conditions. recalling the noun/verb parse that was applied to the processing narrative, review all "control items" as possible CSPEC inputs/outputs. recalling the noun/verb parse that was applied to the processing narrative, review all "control items" as possible CSPEC inputs/outputs.

45. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 45 The Control Model the control flow diagram is "superimposed" on the DFD and shows events that control the processes noted in the DFD control flows—events and control items—are noted by dashed arrows a vertical bar implies an input to or output from a control spec (CSPEC) — a separate specification that describes how control is handled a dashed arrow entering a vertical bar is an input to the CSPEC a dashed arrow leaving a process implies a data condition a dashed arrow entering a process implies a control input read directly by the process control flows do not physically activate/deactivate the processes—this is done via the CSPEC

46. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 46 Control Flow Diagram

47. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 47 Control Specification (CSPEC) The CSPEC can be: state diagram (sequential spec) state transition table decision tables activation tables combinatorial spec

48. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 48 Guidelines for Building a CSPEC list all sensors that are "read" by the software list all interrupt conditions list all "switches" that are actuated by the operator list all data conditions recalling the noun-verb parse that was applied to the software statement of scope, review all "control items" as possible CSPEC inputs/outputs describe the behavior of a system by identifying its states; identify how each state is reach and defines the transitions between states focus on possible omissions... a very common error in specifying control, e.g., ask: "Is there any other way I can get to this state or exit from it?"

49. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 49 Class-Based Modeling Identify analysis classes by examining the problem statement Identify analysis classes by examining the problem statement Use a “grammatical parse” to isolate potential classes Use a “grammatical parse” to isolate potential classes Identify the attributes of each class Identify the attributes of each class Identify operations that manipulate the attributes Identify operations that manipulate the attributes

50. Grammatical Parse The Safehome security function enables the homeowner to configure the security system when it is installed, monitors all sensors connected to the security system, and interacts with the homeowner through the Internet, a PC, or a control panel. During installation, the Safehome PC is used to program and configure the system. Each sensor is assigned a number and type, a master password is programmed for arming and disarming the system, and telephone number(s) are input for dialing when a sensor event occurs. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 50

51. The Safehome security function enables the homeowner to configure the security system when it is installed, monitors all sensors connected to the security system, and interacts with the homeowner through the Internet, a PC, or a control panel. The Safehome security function enables the homeowner to configure the security system when it is installed, monitors all sensors connected to the security system, and interacts with the homeowner through the Internet, a PC, or a control panel. During installation, the Safehome PC is used to program and configure the system. Each sensor is assigned a number and type, a master password is programmed for arming and disarming the system, and telephone number(s) are input for dialing when a sensor event occurs. During installation, the Safehome PC is used to program and configure the system. Each sensor is assigned a number and type, a master password is programmed for arming and disarming the system, and telephone number(s) are input for dialing when a sensor event occurs. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 51

52. Verbs are Safehome processes Verbs are Safehome processes Nouns are external entities, data or control objects, or data stores (or attributes of data objects) Nouns are external entities, data or control objects, or data stores (or attributes of data objects) These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 52

53. Potential classes Safehome security function Safehome security function Homeowner Homeowner security system security system Sensors Sensors Internet Internet PC PC control panel. control panel. installation installation Number Number Type Type master password master password telephone number(s) telephone number(s) sensor event sensor event These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 53

54. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 54 Analysis Classes External entities (e.g., other systems, devices, people) that produce or consume information to be used by a computer-based system. External entities (e.g., other systems, devices, people) that produce or consume information to be used by a computer-based system. Things (e.g, reports, displays, letters, signals) that are part of the information domain for the problem. Things (e.g, reports, displays, letters, signals) that are part of the information domain for the problem. Occurrences or events (e.g., a property transfer or the completion of a series of robot movements) that occur within the context of system operation. Occurrences or events (e.g., a property transfer or the completion of a series of robot movements) that occur within the context of system operation. Roles (e.g., manager, engineer, salesperson) played by people who interact with the system. Roles (e.g., manager, engineer, salesperson) played by people who interact with the system. Organizational units (e.g., division, group, team) that are relevant to an application. Organizational units (e.g., division, group, team) that are relevant to an application. Places (e.g., manufacturing floor or loading dock) that establish the context of the problem and the overall function of the system. Places (e.g., manufacturing floor or loading dock) that establish the context of the problem and the overall function of the system. Structures (e.g., sensors, four-wheeled vehicles, or computers) that define a class of objects or related classes of objects. Structures (e.g., sensors, four-wheeled vehicles, or computers) that define a class of objects or related classes of objects.

55. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 55 Selecting Classes—Criteria classes maybe useful if … 2- needed services: have a set of operations to change its attributes. 3- multiple attributes: to be major enough. 4- common attributes: for all its instances. 5- common operations: for all its instances. 6- essential requirements: those who provide essential inf., usually external entities. usually external entities. 1- retained information: its inf. shall be remembered.

56. Potential classes: reject or accept according to the criteria? Safehome security function Safehome security function Accepted Accepted Homeowner Homeowner Reject, 1,2 fail, although 6 applies Reject, 1,2 fail, although 6 applies security system security system The same as Safehome security function The same as Safehome security function Sensors Sensors Accepted: all apply Accepted: all apply Internet Internet ? PC PC ? control panel. control panel. Accepted: al apply Accepted: al apply These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 56

57. Installation Installation rejected rejected Number, Type Number, Type Rejected, attributes of sensor, 3 fails Rejected, attributes of sensor, 3 fails master password master password rejected, 3 fails rejected, 3 fails telephone number(s) telephone number(s) Rejected, 3 fails Rejected, 3 fails sensor event sensor event Accepted, all apply Accepted, all apply Audible alarm Audible alarm Accepted:2,3,4,5,6 apply Accepted:2,3,4,5,6 apply These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 57

58. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 58 Class Diagram Class name attributes operations Identification inf Alatm respose inf Activation/deactivation inf

59. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 59 Class Diagram

60. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 60 CRC Modeling Analysis classes have “responsibilities” Analysis classes have “responsibilities” Responsibilities are the attributes and operations encapsulated by the class Responsibilities are the attributes and operations encapsulated by the class Analysis classes collaborate with one another Analysis classes collaborate with one another Collaborators are those classes that are required to provide a class with the information needed to complete a responsibility. Collaborators are those classes that are required to provide a class with the information needed to complete a responsibility. In general, a collaboration implies either a request for information or a request for some action. In general, a collaboration implies either a request for information or a request for some action.

61. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 61 CRC Modeling

62. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 62 Class Types Entity classes, also called model or business classes, are extracted directly from the statement of the problem (e.g., FloorPlan and Sensor). (persist) Entity classes, also called model or business classes, are extracted directly from the statement of the problem (e.g., FloorPlan and Sensor). (persist) Boundary classes are used to create the interface (e.g., interactive screen or printed reports) that the user sees and interacts with as the software is used. (like cameraWindow) Boundary classes are used to create the interface (e.g., interactive screen or printed reports) that the user sees and interacts with as the software is used. (like cameraWindow) Controller classes manage a “unit of work” from start to finish (design time). That is, controller classes can be designed to manage Controller classes manage a “unit of work” from start to finish (design time). That is, controller classes can be designed to manage the creation or update of entity objects; the creation or update of entity objects; the instantiation of boundary objects as they obtain information from entity objects; the instantiation of boundary objects as they obtain information from entity objects; complex communication between sets of objects; complex communication between sets of objects; validation of data communicated between objects or between the user and the application. validation of data communicated between objects or between the user and the application.

63. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 63 Responsibilities How to allocate responsibilities to classes: System intelligence should be distributed across classes to best address the needs of the problem System intelligence should be distributed across classes to best address the needs of the problem Each responsibility should be stated as generally as possible (high enough in hierarchy) Each responsibility should be stated as generally as possible (high enough in hierarchy) Information and the behavior related to it should reside within the same class (encapsulation) Information and the behavior related to it should reside within the same class (encapsulation) Information about one thing should be localized with a single class, not distributed across multiple classes. Information about one thing should be localized with a single class, not distributed across multiple classes. Responsibilities should be shared among related classes, when appropriate. Responsibilities should be shared among related classes, when appropriate.

64. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 64 Collaborations Classes fulfill their responsibilities in one of two ways: Classes fulfill their responsibilities in one of two ways: A class can use its own operations to manipulate its own attributes, thereby fulfilling a particular responsibility, or A class can use its own operations to manipulate its own attributes, thereby fulfilling a particular responsibility, or a class can collaborate with other classes. a class can collaborate with other classes. Collaborations identify relationships between classes Collaborations identify relationships between classes Collaborations are identified by determining whether a class can fulfill each responsibility itself Collaborations are identified by determining whether a class can fulfill each responsibility itself

65. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 65 Composite Aggregate Class

66. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 66 Reviewing the CRC Model All participants in the review (of the CRC model) are given a subset of the CRC model index cards. All participants in the review (of the CRC model) are given a subset of the CRC model index cards. Cards that collaborate should be separated (i.e., no reviewer should have two cards that collaborate). Cards that collaborate should be separated (i.e., no reviewer should have two cards that collaborate). All use-case scenarios (and corresponding use-case diagrams) should be organized into categories. All use-case scenarios (and corresponding use-case diagrams) should be organized into categories. The review leader reads the use-case deliberately. The review leader reads the use-case deliberately. As the review leader comes to a named object, she passes a token to the person holding the corresponding class index card. As the review leader comes to a named object, she passes a token to the person holding the corresponding class index card. When the token is passed, the holder of the class card is asked to describe the responsibilities noted on the card. When the token is passed, the holder of the class card is asked to describe the responsibilities noted on the card. The group determines whether one (or more) of the responsibilities satisfies the use-case requirement. The group determines whether one (or more) of the responsibilities satisfies the use-case requirement. If the responsibilities and collaborations noted on the index cards cannot accommodate the use-case, modifications are made to the cards. If the responsibilities and collaborations noted on the index cards cannot accommodate the use-case, modifications are made to the cards. This may include the definition of new classes (and corresponding CRC index cards) or the specification of new or revised responsibilities or collaborations on existing cards. This may include the definition of new classes (and corresponding CRC index cards) or the specification of new or revised responsibilities or collaborations on existing cards.

67. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 67 Associations and Dependencies Two analysis classes are often related to one another in some fashion Two analysis classes are often related to one another in some fashion In UML these relationships are called associations In UML these relationships are called associations Associations can be refined by indicating multiplicity (the term cardinality is used in data modeling) Associations can be refined by indicating multiplicity (the term cardinality is used in data modeling) In many instances, a client-server relationship exists between two analysis classes. In many instances, a client-server relationship exists between two analysis classes. In such cases, a client-class depends on the server-class in some way and a dependency relationship is established In such cases, a client-class depends on the server-class in some way and a dependency relationship is established

68. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 68 Association - Multiplicity

69. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 69 Dependencies

70. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 70 Analysis Packages Various elements of the analysis model (e.g., use-cases, analysis classes) are categorized in a manner that packages them as a grouping Various elements of the analysis model (e.g., use-cases, analysis classes) are categorized in a manner that packages them as a grouping The plus sign preceding the analysis class name in each package indicates that the classes have public visibility and are therefore accessible from other packages. The plus sign preceding the analysis class name in each package indicates that the classes have public visibility and are therefore accessible from other packages. Other symbols can precede an element within a package. A minus sign indicates that an element is hidden from all other packages and a # symbol indicates that an element is accessible only to packages contained within a given package. Other symbols can precede an element within a package. A minus sign indicates that an element is hidden from all other packages and a # symbol indicates that an element is accessible only to packages contained within a given package.

71. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 71 Analysis Packages

72. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 72 Behavioral Modeling The behavioral model indicates how software will respond to external events or stimuli. To create the model, the analyst must perform the following steps: The behavioral model indicates how software will respond to external events or stimuli. To create the model, the analyst must perform the following steps: Evaluate all use-cases to fully understand the sequence of interaction within the system. Evaluate all use-cases to fully understand the sequence of interaction within the system. Identify events that drive the interaction sequence and understand how these events relate to specific objects. Identify events that drive the interaction sequence and understand how these events relate to specific objects. Create a sequence for each use-case. Create a sequence for each use-case. Build a state diagram for the system. Build a state diagram for the system. Review the behavioral model to verify accuracy and consistency. Review the behavioral model to verify accuracy and consistency.

73. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 73 State Representations In the context of behavioral modeling, two different characterizations of states must be considered: In the context of behavioral modeling, two different characterizations of states must be considered: the state of each class as the system performs its function and the state of each class as the system performs its function and the state of the system as observed from the outside as the system performs its function the state of the system as observed from the outside as the system performs its function

74. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 74 State Diagram for the ControlPanel Class

75. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 75 The States of a System state—a set of observable circum- stances that characterizes the behavior of a system at a given time state—a set of observable circum- stances that characterizes the behavior of a system at a given time state transition—the movement from one state to another state transition—the movement from one state to another event—an occurrence that causes the system to exhibit some predictable form of behavior event—an occurrence that causes the system to exhibit some predictable form of behavior action—process that occurs as a consequence of making a transition action—process that occurs as a consequence of making a transition

76. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 76 Behavioral Modeling make a list of the different states of a system (How does the system behave?) make a list of the different states of a system (How does the system behave?) indicate how the system makes a transition from one state to another (How does the system change state?) indicate how the system makes a transition from one state to another (How does the system change state?) indicate event indicate event indicate action indicate action draw a state diagram or a sequence diagram draw a state diagram or a sequence diagram

77. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 77 Sequence Diagram

78. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 78 Writing the Software Specification Everyone knew exactly what had to be done until someone wrote it down!

79. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 79 Specification Guidelines

80. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 80 Specification Guidelines

81. These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 81 Specification Guidelines

82. Excercises 7.1 a,b 7.1 a,b 8.6a, 8.7a, 8.9a, 8.12 8.10,8.14,8.15,8.18 8.6a, 8.7a, 8.9a, 8.12 8.10,8.14,8.15,8.18 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 6/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001, 2005 82