1. COS50-3 OOSD INTRODUCTION TO OOSD (Week 1) November 7, 2018
Marc Conrad/Dayou Li

2. AIMS AND OBJECTIVES
To understand the software development process, including requirement specification, analysis, design, implementation and testing.
To acquire various methodologies in software development,
To understand the process of modelling real world problems and systems using UML,
To develop skills on object oriented software development.
November 7, 2018
Marc Conrad/Dayou Li

3. EXPECTION AND EXAM Design solutions to complex problems
Evaluate the significance of the object oriented paradigm in the production of complex software
Appraise current and future technologies in their industrial context.
Assignments and Exam:
-- Assignments: 50%
-- Final exam (QuestionMark): 50%
November 7, 2018
Marc Conrad/Dayou Li

4. TEACHING SCHEDULE
“Introduction” – outline OOSD, including the general process of software development, basic methodologies, preliminary on UML and Rational Rose.
“Use cases: a useful tool for capturing requirements” – basic concepts of a use case, reasons for using use cases and how to apply it to capture user requirements.
“Analysis modelling” – management of a software process, analysis models, sequence diagram and CRC card.
“OO designing” – function oriented design, object oriented design and comparison, class diagram and statechart diagram
“Software patterns”
November 7, 2018
Marc Conrad/Dayou Li

5. GOOD BOOKS
Object-Oriented Software Engineering -- a use case driven approach (revised edition) by Ivar Jacobson
UML Distilled (2nd Edition) by Martin Fowler
Software Engineering (4th Edition) by Ian Sommerville
Developing Applications with Java and UML by Paul R and Reed Jr
An Introduction of Object Oriented Programming with Java (2nd Edition) by C Thomas Wu
November 7, 2018
Marc Conrad/Dayou Li

6. SOFTWARE PROCESS A software Process: not just coding
London Ambulance Service (LAS) -- a true disaster of software engineering.
-- Time: from early 1980’s to 1992,
-- Total cost: £7.5 million,
-- Result: abandoned
November 7, 2018
Marc Conrad/Dayou Li

7. SOFTWARE PROCESS (Cont’d)
LAS manual system:      
November 7, 2018
Marc Conrad/Dayou Li

8. SOFTWARE PROCESS (Cont’d)
LAS required system: 
Mapping system
Computer aided dispatch System  
Auto Vehicle Location System
Radio Interface System  
Auto Call Distributor  
November 7, 2018
Marc Conrad/Dayou Li

9. SOFTWARE PROCESS (Cont’d)
Things went wrong from very beginning:
-- End-user hostility -- lack of consultation,
-- Official project issue report process was not followed,
-- Problems were left in later stages, ignored and programmed,
-- Hidden and newly introduced bugs,
-- Test team had no knowledge about changes.
Lessons was taught
-- Software development is like other engineering processes,
-- The process must be strictly followed.
November 7, 2018
Marc Conrad/Dayou Li

10. METHODOLOGIES
Waterfall approach -- requirement, design, coding and test stages, one after another,
Exploratory programming -- working system plus improvement,
Prototyping -- establishing system requirements plus re-implementation,
Formal transformation -- transforming specifications into program,
System assembly from reusable components .
November 7, 2018
Marc Conrad/Dayou Li

11. WHATERFALL MODEL Requirement Specification Analysis Design Implemen-
tation
Testing
November 7, 2018
Marc Conrad/Dayou Li

12. WHATERFALL MODEL (Cont’d)
Requirement specification -- collecting and understanding clients’ requirements.
Analysis -- establishing system’s services, constraints and goals by consultation with system’s users.
Design -- establishing an overall system architecture, including program units and interface between those units,
Implementation -- realising programs or program units and verifying that each unit meets its specification,
November 7, 2018
Marc Conrad/Dayou Li

13. WHATERFALL MODEL (Cont’d)
integration -- integrating the individual program units are testing as a complete system to ensure the the system satisfy users requirements.
Testing -- verification (Does the system work right?) and validation (Do we build up a right system?).
November 7, 2018
Marc Conrad/Dayou Li

14. WHATERFALL MODEL (Cont’d)
Design
Testing
Analysis
Implemen-
tation
User
requirement
November 7, 2018
Marc Conrad/Dayou Li

15. CRISIS ARE STILL WITH US
31% of project will get cancelled before they ever get complete
88% of all projects are over schedule, over budget or both
for every 100 projects started, there are 94 restarts
Average cost overun is 189% of original estimate
Average time overun is 222% of original estimate
November 7, 2018
Marc Conrad/Dayou Li

16. CRISIS ARE STILL WITH US
Causes:
-- Incomplete requirements -- 13%
-- Lack of user involvement %
-- Lack of resources %
-- Unreasonable expectations %
-- No management support %
-- Specification changes %
-- Lack of planning %
-- No longer needed %
Reason and solution:
-- Methodologies are difficult to follow
-- Modelling language for implement the methods
November 7, 2018
Marc Conrad/Dayou Li

17. INTRODUCTION TO UML UML -- Unified Modelling Language
It would help us (software engineers) to modelling real world problems and systems, e.g.
-- Use Cases: to capture requirements
-- Analysis modelling: to establish system specifications
-- Design modelling: to design a system
-- Package: large systems management
November 7, 2018
Marc Conrad/Dayou Li

18. INTRODUCTION TO UML
It allows implementation-independent specification of:
-- user/system interactions (required behaviors)
-- partitioning of responsibility (OO)
-- integration with larger or existing systems
-- data flow and dependency
-- operation orderings (algorithms)
-- concurrent operations
November 7, 2018
Marc Conrad/Dayou Li

19. CONTENTS OF UML Use cases,
Interaction diagrams (Sequence Diagram, CRC, Collaboration Diagram)
Class Diagram (aggregations, composites, interfaces and realisations)
Package
Activity Diagram
State Diagram, State Chart, and Data Flow Diagram
November 7, 2018
Marc Conrad/Dayou Li

20. RATIONAL ROSE Rose is one of products from Rational Software.
It is an expensive CASE (Computer-Aided Software Engineering) tool for object-oriented modeling.
Based on UML (more or less).
It provides semantics (a ‘compiler’) for UML.
It has a reasonably intuitive GUI similar to standard drawing programs, like Illustrator, and is available for Windows and other platforms.
It makes creating and maintaining your UML diagrams easier (or at least more consistent).
Has many bizarre features, including generation of C++ (and other) code from your diagrams.
November 7, 2018
Marc Conrad/Dayou Li

21. RATIONAL ROSE (Cont’d)
You can visit their website:
Getting the Evaluation copy (limited to 15 days):
Rational Rose is also Installed in our CIS Lab (Room 015)
Our practicals will be based on the software.
November 7, 2018
Marc Conrad/Dayou Li

22. RATIONAL ROSE (Cont’d)
Why do we need the Rational Rose? -- We use it to create a series of models for all the steps of OOSD
-- Each model contains views, diagrams, and specifications to visualise and manipulate the elements in the model
-- There are many views of each underlying element
-- Every “object” in the design is represented once in the Rose “model”
-- Rose maintains a consistent semantic representation in the “model”
November 7, 2018
Marc Conrad/Dayou Li

23. RATIONAL ROSE (Cont’d)
What does Rational Rose look like?
-- Standard toolbar
-- Diagram toolbar
-- Browser: a drop-down list of things in your model
-- Documentation window: where you can add notes to a thing in your model
-- Diagram windows: where you draw your pictures
-- Specifications
-- Status bar
November 7, 2018
Marc Conrad/Dayou Li

24. Standard Toolbar Browser Diagram Toolbar Diagram Window Documen-tation
Status
Bar
November 7, 2018
Marc Conrad/Dayou Li

25. SUMMARY Credit Scheme Software process Introduction of UML
Introduction to Rational Rose
November 7, 2018
Marc Conrad/Dayou Li

26. COS50-3 OOSD REQUIREMENT MODEL: USE CASE DIAGRAM (Week 2)
November 7, 2018
Marc Conrad/Dayou Li

27. MODELLING System development is model building
Complexity -- hard to handle many requirements at the same time
Modelling -- an organised way to handle requirements
Models -- standard representations so that everyone can follow
Various types of models -- for different purposes and stages in software development
November 7, 2018
Marc Conrad/Dayou Li

28. MODELLING (Cont’d) Various types of models Requirement model:
capture functional/user’s requirements
Analysis model:
give the system a robust and changeable structure
Design model:
adopt and refine the structure to the current implementation environment
Implementation model:
implement the system
Test model:
verify the system
November 7, 2018
Marc Conrad/Dayou Li

29. MODELLING (Cont’d) Architecture of a modelling language
Model architecture -- a set of modelling language, notation or modelling technique. It contains:
Syntax -- how it looks
Semantics -- what it means
Pragmatics -- heuristics and rules of thumb for using it
November 7, 2018
Marc Conrad/Dayou Li

30. REQUIREMENT MODEL What are requirements?
Statements of a customer/end-user’s needs and expectations
Descriptions of essential characteristics of the customer/end-user,s goal
Requirements should be problem based and not describe the solution
November 7, 2018
Marc Conrad/Dayou Li

31. USE CASE DIAGRAM Syntax: Actor -- Use case -- Relationship --
System border --
November 7, 2018
Marc Conrad/Dayou Li

32. Rational Rose & Use case diagrams
No system border in Rational Rose!
November 7, 2018
Marc Conrad/Dayou Li

33. USE CASE DIAGRAM (Cont’d)
Semantics:
An actor represents anything that is outside of the system and that needs to exchange information with the system.
-- An individual person (end-user)
-- A group of people
-- An individual can play different roles
-- A machine
-- …..
November 7, 2018
Marc Conrad/Dayou Li

34. USE CASE DIAGRAM (Cont’d)
A use case represents a special sequence of events triggered by an actor.
Example: making an initialisation process user-friendly.
being willing to initialise
choosing a variable
assigning a “wrong” value
assigning a “correct” value
sending a list of variables
giving the range of the variable
giving a warning signal
giving acknowledgement
A use case
November 7, 2018
Marc Conrad/Dayou Li

35. USE CASE DIAGRAM (Cont’d)
Relationship represents information exchange between an actor and a use case and between two use cases.
We have different types of relationship existing between an actor and a use case and between two use cases.
Ordinary relationship: showing that there is a relationship between an actor and a use case or between two use cases.
We use symbol to represent this type of relationship.
November 7, 2018
Marc Conrad/Dayou Li

36. USE CASE DIAGRAM (Cont’d)
Extend relationship exists between two similar use cases where the second one has some extra activities, that is the activities of the first use case are extended in the second one.
The first use case sends information to the second use case to invoke the extra activities.
Terms:
-- the first use case: base use case,
-- the second use case: extending use case
-- the information: extension point.
November 7, 2018
Marc Conrad/Dayou Li

37. USE CASE DIAGRAM (Cont’d)
Example -- think about an Internet search engine. You type in key words and press “submit”. This will trigger a sequence of activities happening in a search engine.
-- If there is no spelling mistake in the key words, the search engine will go ahead to search for items.
--If there is a spelling mistake, the search engine will ask you to confirm the key word.
<<extend>>
search
confirm
Extension point:
spelling info
(spelling info)
November 7, 2018
Marc Conrad/Dayou Li

38. USE CASE DIAGRAM (Cont’d)
Generalisation relationship exists between two similar use cases. The base use case includes basic activities and the second use case contains the alternative activities. Both use cases handle the same thing but the base use case deals with the general situation and the second one deals with special cases.
Generalisation relationship says that alternatives exist.
November 7, 2018
Marc Conrad/Dayou Li

39. USE CASE DIAGRAM (Cont’d)
Example
-- Suppose in an Internet search engine, we have designed two sequences of searching activities: one sequence of activities is the normal search and the other one is intelligent search which is for academy.
-- So we have two use cases corresponding to these two sequences of activities: one contains the normal search activities (called base use case) and the other contains the intelligent search activities.
-- Both handle the request of search, but the second one deal with special request -- academic request.
Normal
search
Intelligent
search
November 7, 2018
Marc Conrad/Dayou Li

40. USE CASE DIAGRAM (Cont’d)
If two or more use cases have a chunk of same activities, we can create a new use case that contains this chunk of activities. The relation from the original use cases to the new one is the Include relationship, which means that the original use cases involve the activities of the new use case. They share the activities of the new use case.
By having the new use case and the include relationship, we can avoid the repeating of the same activities in different use cases.
November 7, 2018
Marc Conrad/Dayou Li

41. USE CASE DIAGRAM (Cont’d)
Example:
-- Both the normal and the intelligent search engines need to read the key words you typed in.
-- The activity of reading key words can then be picked up from the two use cases and placed into a new use case.
normal
intelligent
<<include>>
New case
November 7, 2018
Marc Conrad/Dayou Li

42. USE CASE DIAGRAM (Cont’d)
Pragmatics:
Identify system border -- Which action should be taken by actors and which by system? This is vital important.
Identify actor(s) -- What are “objects” outside of the system which want to exchange information with the system? Can we classify them?
Identify use case(s) -- What are the main tasks of each actor? An use case should link to a main task and contain a complete course of events related to the task.
Add relationship -- We need to pay extra attention on those between use cases.
November 7, 2018
Marc Conrad/Dayou Li

43. CASE STUDY A recycling machine
System description: The system controls a recycling machine for returnable bottles, cans and crates. The machine can be used by several customers at the same time and each customer can return all three types of item on the same occasion.
November 7, 2018
Marc Conrad/Dayou Li

44. CASE STUDY (Cont’d)
The system has to check, for each item, what type has been returned. The system will register how many items each customer returns and when the customer asks for a receipt, the system will print out what was deposited , the value of the returned items and the total return sum that will be paid to the customer. An operator also uses the system. He asks for a printout of the total number of items that have been deposited at the end of each day. He has right to change the deposit values of the items through a console. When anything wrong with the machine, the operator will be called by a special alarm signal.
November 7, 2018
Marc Conrad/Dayou Li

45. CASE STUDY (Cont’d) Identify actors: operator customer
November 7, 2018
Marc Conrad/Dayou Li

46. CASE STUDY (Cont’d) Identify use cases: Generating daily report
Returning items
Changing item values
November 7, 2018
Marc Conrad/Dayou Li

47. CASE STUDY (Cont’d) “Entire” use case model: November 7, 2018
Marc Conrad/Dayou Li

48. DOCUMENTATION Events/activities of each use case must be documented.
These are activities that need to be documented
Insert an item
customer
Register
Classify
Calculate value
Returning item
Request Receipt
Accumulate
Print out item,s value and sum
November 7, 2018
Marc Conrad/Dayou Li

49. ACTIVITY DIAGRAM
Activity diagram -- showing the sequence of events triggered by an actor and the relationship among the events contained in an use case
Events -- being represented as activity states (of an use case) or activity for short.
November 7, 2018
Marc Conrad/Dayou Li

50. ACTIVITY DIAGRAM (Cont’d)
Syntax
Activity
Fork
Branch
Join
Merge
November 7, 2018
Marc Conrad/Dayou Li

51. ACTIVITY DIAGRAM (Cont’d)
Semantics
Activity -- event which is the response to a stimulus from an actor
Branch -- conditional selection, only one outgoing transition can be taken
Merge -- the end of conditional behaviour started by a branch
Fork -- the start of parallel operations
Join -- the end of parallel operations
November 7, 2018
Marc Conrad/Dayou Li

52. ACTIVITY DIAGRAM (Cont’d)
Example:
Recycling machine -- customers return items
When a customer returns an item to the machine, the following activities should happen in the system:
-- Register the item
-- Classify (crate | can | bottle)
-- Increment item quantity
-- Increment item value
November 7, 2018
Marc Conrad/Dayou Li

53. register
Inc item
Inc value
November 7, 2018
Marc Conrad/Dayou Li

54. Rational Rose activity diagram

55. CASE STUDY
Wessex Fox is a small bus company operating a number of different routes. Each route has a unique route number and is divided into a number of stages. The same stage may occur in several different routes. For example, both the route from Southampton to Fawley and the route from Southampton to Lyndhurst include the stage Millbrook - Totton. Fares are allocated on the basis of how many stages a passenger's journey incorporates.
Each route is associated with a number of scheduled departure times for particular days of the week and estimated arrival times. For reasons of safety, no two buses can depart at exactly the same time.
Once a week, a particular bus and bus driver are allocated to each departure scheduled for the following week. This information is only kept during that current week. The company uses this information to produce a bus timetable for the use of the drivers.
November 7, 2018
Marc Conrad/Dayou Li

56. CASE STUDY (Cont’d) Step 1: System border Wessex Fox November 7, 2018
Marc Conrad/Dayou Li

57. CASE STUDY (Cont’d) Step 2: Actors: -- Drivers, -- Time Table Makers,
-- Manager.
November 7, 2018
Marc Conrad/Dayou Li

58. CASE STUDY (Cont’d) Step 3: Use case:
Driver: request time tables, drive buses, collect fares;
Time table maker: collect departure times, arrival times and information about the allocation of bus drivers, generate new time tables, delete out of date time tables.
Manager: Allocates buses and drivers.
November 7, 2018
Marc Conrad/Dayou Li

59. CASE STUDY (Cont’d) Request DriveBus CollectFare CollectInfo Generate
Allocate
Read
<<include>>
Write
Time table maker
Driver
Manager
November 7, 2018
Marc Conrad/Dayou Li

60. Case Study in Rational Rose
November 7, 2018
Marc Conrad/Dayou Li

61. SUMMARY Various models Use case diagram Activity diagram
November 7, 2018
Marc Conrad/Dayou Li

62. Object Oriented Analysis
COS50-3 OOSD
Object Oriented Analysis
(Week 3)
November 7, 2018
Marc Conrad/Dayou Li

63. OBJECT
An object is an entity which consists of a number of operations and a state which remembers the effect of the operations.
State is regarded as information which is saved in a set of variables.
Operations read and/or affect the information.
The only part that can be seen by an outsider is the operations. For this reason, operations are also known as behaviours.
Information is hidden to the outsider.
November 7, 2018
Marc Conrad/Dayou Li

64. OBJECT (Cont’d) Example: a person as an object Information: Behaviour:
Name,
Age,
Address,
Friends,
...
Behaviour:
jump
bend legs
stretch legs
lift arms,
...
walk
talk
November 7, 2018
Marc Conrad/Dayou Li

65. CLASS and INSTANCE
Class is a template or abstract description of the same type of objects. It defines the common features of the objects, that is the operations and information structure.
Instance is an object created from a class.
An instance’s behaviour and information structure is defined in the class.
Its current state (values of instance variables) is determined by operations performed on it.
November 7, 2018
Marc Conrad/Dayou Li

66. INHERITANCE
Inheritance takes place when a subclass of a superclass is created.
A subclass inherits behaviours and information structure (class members) from its parent class.
It can refine the operations and can even add some extra operations and information.
Note: not all operations and information a subclass can inherit. Pay attention to the the specifiers of class members of a superclass.
Access private members is not easy.
November 7, 2018
Marc Conrad/Dayou Li

67. POLYMORPHISM
Very original meaning -- Microorganism propagates itself and no two individuals are exactly the same. So we obtain a variety of individuals.
Original meaning -- the sender of a stimulus doesn’t need to know the receiver’s class.
Extension -- different receivers can interpret the message in their own way.
Consequence -- different receivers can response to the same stimulus based on their interpretation. So we can have a variety of objects who process the same piece of data in different ways.
Method overloading and overwriting.
November 7, 2018
Marc Conrad/Dayou Li

68. ENCAPSULATION
Encapsulation is the process of hiding the implementation details of an object.
The only access to manipulate the object data is through its interface.
It protects an object’s internal state from being corrupted by other objects.
Also, other objects are protected from changes in the object implementation.
Encapsulation allows objects to be viewed as ‘black boxes’.
Communication is achieved through an ‘interface’.
November 7, 2018
Marc Conrad/Dayou Li

69. ANALYSIS
In software engineering, analysis is the process of converting the user requirements to system specification (system means the software to be developed).
System specification, also known as the logic structure, is the developer’s view of the system.
Function-oriented analysis -- concentrating to the decomposition a complex function to simply ones.
Object-oriented analysis -- identifying objects and the relationship between objects. (An object-oriented model of a system consists of a number of objects which are the parts of the system.)
November 7, 2018
Marc Conrad/Dayou Li

70. OO ANALYSIS OO analysis contains the following activities:
-- identifying objects: objects must be essential, i.e. always exist, so the system is stable,
-- organising the objects: classifying the objects identified, so similar objects can later be defined in the same class,
-- identifying relationships between objects: this helps to determine inputs and outputs of an object,
-- defining operations of the objects: the way of processing data within an object,
-- defining objects internally: information held be the objects.
November 7, 2018
Marc Conrad/Dayou Li

71. OO ANALYSIS MODEL
A model is required to represent the system specification.
The model must be robust and stable. To achieve these, the model must be implementation environment independent, so that any change in the implementation environment will not affect the logic structure of the system.
The model must be able to capture information, behaviour (operations) and presentation (inputs and outputs).
November 7, 2018
Marc Conrad/Dayou Li

72. OO ANALYSIS MODEL
The model is defined in information -- behaviour -- presentation space.
behaviour
information
presentation
November 7, 2018
Marc Conrad/Dayou Li

73. OO ANALYSIS MODEL (Cont’d)
Syntax
Within an use case, we employ three types of objects (in Rational Rose, they are known as three types of entities or stereotypes):
Entity
Boundary / Interface
Control
On information -- behaviour plane and incline to information axis
On the presentation axis
On information -- behaviour plane but incline towards behaviour axis
November 7, 2018
Marc Conrad/Dayou Li

74. OO ANALYSIS MODEL (Cont’d)
Semantics
An entity object models information that shows the state of a system. This information is often used to record the effects of operations and therefore is related to the behaviours of the system.
A boundary/interface object models inputs and outputs and operations that process them.
A Control object models functionality/operations regarding to validate and decide whether to process and pass information from interface object to entity object, or the way around.
November 7, 2018
Marc Conrad/Dayou Li

75. OO ANALYSIS MODEL (Cont’d)
Pragmatics
Identifying interface objects -- functions directly related to actors.
Identifying entity objects -- information used in an use case and functions of processing the information.
Identifying control object -- functions that link interface objects and entity objects
November 7, 2018
Marc Conrad/Dayou Li

76. OO ANALYSIS MODEL (Cont’d)
Example: Recycling machine
Three tasks are often tangled together
We normally start from the refinement of the use case diagram.
Then we identify objects.
At the “same time”, we organise and identify relationships.
November 7, 2018
Marc Conrad/Dayou Li

77. OO ANALYSIS MODEL (Cont’d)
Refinement of the use case diagram
-- Refine use cases by considering include, extend and generalisation.
Print
<<include>>
Return item
Generating daily report
November 7, 2018
Marc Conrad/Dayou Li

78. OO ANALYSIS MODEL (Cont’d)
-- Refine actors by considering superclass/subclass and inheritance.
Receipt receiver
inheritance
Customer
Operator
November 7, 2018
Marc Conrad/Dayou Li

79. OO ANALYSIS MODEL (Cont’d)
-- Refinement also includes adding use cases which are “forgotten” at the previous stage.
Operator
Customer
Print
Return item
Gene D Report
Change item
Handle alarm
R Receiver
November 7, 2018
Marc Conrad/Dayou Li

80. OO ANALYSIS MODEL (Cont’d)
Identify boundary/interface objects
R Receiver
Receipt printer
Customer
Operator panel
Operator
Customer panel
Alarm
November 7, 2018
Marc Conrad/Dayou Li

81. OO ANALYSIS MODEL (Cont’d)
Identify relationship (also know as association) between the identified objects.
Customer panel
Receipt printer
Operator panel
Alarm
November 7, 2018
Marc Conrad/Dayou Li

82. OO ANALYSIS MODEL (Cont’d)
When a customer returns a deposit item, it is measured by the system. The measurements are used to determine what kind of can, bottle or crate has been returned. If acceptable, the total number of items of this type returned by the customer increments. If not, the light for “Not Valid” is highlighted on customer panel.
When the customer presses the receipt button, the printer prints the date. The total number of items he returned and the lump sum is calculated. The following is printed out:
customer number, number returned, deposit value, total of this type and lump sum
November 7, 2018
Marc Conrad/Dayou Li

83. OO ANALYSIS MODEL (Cont’d)
Identify entity objects. (Let us focus on return item use case.)
-- long term information (for all customer): deposit values of bottle, can and crate,
-- short term information (for a customer): the total number of items of each type returned by the customer, the total number of items he returned and the lump sum should be paid to him.
November 7, 2018
Marc Conrad/Dayou Li

84. OO ANALYSIS MODEL (Cont’d)
Generalisation
Receipt basis
Deposit items
Storing short term info
Can
Bottle
Crate
Storing long term info
November 7, 2018
Marc Conrad/Dayou Li

85. OO ANALYSIS MODEL (Cont’d)
When a customer returns a deposit item, it is measured by the system. The measurements are used to determine what kind of can, bottle or crate has been returned. If acceptable, the total number of items of this type returned by the customer increments. If not, the light for “Not Valid” is highlighted on customer panel.
When the customer presses the receipt button, the printer prints the date. The total number of items he returned and the lump sum is calculated. The following is printed out:
customer number, number returned, deposit value, total of this type and lump sum
November 7, 2018
Marc Conrad/Dayou Li

86. OO ANALYSIS MODEL (Cont’d)
Identify control objects. (We still focus on return item use case.)
-- There are entity and boundary objects in this use case.
-- Items coming from customer panel need to be measured and decision on whether passing the information needs to be made according the measurement.
-- decision on whether print out information also needs to be made.
November 7, 2018
Marc Conrad/Dayou Li

87. OO ANALYSIS MODEL (Cont’d)
deposit item receiver
receipt basis
deposit items
Customer panel
Receipt printer
November 7, 2018
Marc Conrad/Dayou Li

88. OO ANALYSIS MODEL (Cont’d)
Customer panel
Receipt printer
Deposit item receiver
Receipt basis
Deposit items
can
bottle
crate
November 7, 2018
Marc Conrad/Dayou Li