Analysis Class Diagrams And Communication/Sequence Diagrams For Record New Tour Use Case

What is meant by an Analysis Class Diagram and How it is Useful

a). In your own words, briefly describe what is meant by an Analysis Class

Diagram, and how class diagrams can be useful in systems analysis and design. 

By definition, class diagrams are used to describe systems using relationships, operations and attributes between classes. Unified Modeling Language alias UML treats these diagrams as structure diagrams. They are drawn to suit the principles of object oriented programming. This orientation is useful in identifying the interaction between various objects. The class diagram is a collective structure that combines the behaviors of objects. If objects have similar properties, they are grouped together. In simper terms, objects with mutual properties are grouped together into a single class. 

Activity class diagrams are useful in creating models. With the help of UML, intersections, relationships, attributes and operations you can create models. The class diagram helps in identifying paths between classes through associations and aggregations. The diagrams can be used to pass properties and different types of behaviors between classes too! These are considered as generalizations. The class diagram is one of the most critical and essential forms of UML diagrams. They are required to visualize software development. The class diagrams can be used to illustrate the overall structure of systems in a detailed fashion. The class diagrams show all attributes, inter-relationships and operations. 

Activity class diagrams serve as the heart of any UML. They are based on object oriented programing and can be implemented throughout the project. During the phase of analysis, class diagrams appear as domain models. They are used to represent reality between classes. During the phase of design, the class diagrams can be used to model the entire software. And, during the phase of implementation, class diagrams help in generating source code. Activity class diagrams can be used to make software development easier and structured. These diagrams serve as the foundation of all software.

Class diagrams represent huge volumes of objects or class instances with the following common attributes:

• Semantics
• Behavior
• Properties

Activity class diagrams have attributes and operations. The attributes are known as class properties. They depend on a single class. However, the value of attributes within a class can differ greatly. Classes have operations to define its functionality. Operations are nothing but behaviors of the class. The operations are implemented using well-defined methods. Operations can be used to access attributes and modify them.

b). Draw an Analysis Class Diagram for the ‘Record New Tour’ Use Case, using the Use Case description given. This should include all required boundary, control and entity classes with their associations and attributes. Your diagram should be drawn using the Enterprise Architect software, and copied and inserted as a picture into your document.  

Draw an Analysis Class Diagram for the ‘Record New Tour’ Use Case

c). Write a brief summary of the decisions made whilst drawing the diagram,and your reasons for making them. 

During the design of this class diagram, the following assumptions are made:

• Administrative staff have the liberty to assign roles and responsibilities to clerical assistants.
• Clerical assistants are responsible for adding, modifying and deleting tours.
• Clerical assistants are responsible for adding, modifying and deleting customers.
• Clerical assistants are responsible for raising invoices, estimating tours and seeking approval.
• Clerical assistants are responsible for discussing tour rates, venues, schedules and guides with finance officers.

• Clerical Assistant
• Financial Officer/Branch Manager
• Customer
• Tour Leader/Driver

• Clerical Assistant identifies new Tours from Financial Officer
• Clerical Assistant updates tour database with new tour information
• Clerical Assistant introduces new tours to customers
• Clerical Assistant notifies drivers about new tours
• Clerical Assistant notifies tour leaders about new tours

a). In your own words, briefly describe what is modelled in a Communication Diagram, and how Communication Diagrams can be useful in systems analysis and design 

By definition, the communication diagram is an integral part of UML diagrams. It gives a graphical representation of how objects interact between one another. The interactions can be for a specific use case scenario, communication between classes and the execution of operations. It emphasizes on the system’s overall structure. Several communication diagrams can be drawn to enact a specific scenario. Communication diagrams can be used to identify complex behaviors. The communication diagram is similar to sequence diagrams. It is quite similar to sequence diagrams. However, it concentrates on the chronology of messages between objects. 

The communication diagram showcases all objects (these are instances of classes), actors and communication links. These links are also known as instance links. And, the messages shared between objects are shown as a part of the communication diagram too. The messages are numbered to show the instance they are transferred between two interacting objects. The sequence numbers are important because they represent the order in which messages could be exchanged. The communication diagram supports interactions in all directions.

b). Draw a Communication Diagram for the use case ‘Record New Tour’, using the Use Case description given. This should include all control, boundary and entity objects involved in the scenario and sufficient detail of the messages to show that the interaction is feasible and would meet the system requirements. Your diagram should be drawn using the Enterprise Architect software, and copied and inserted as a picture into your document.

The communication diagram is useful in refining a description or use case behavior. The approach is extremely useful in various stages of requirements analysis. That is because the communication diagram helps in identifying all associations and classes that were not seen during the initial stages of design. For example, interactions between the Clerical Assistants and Financial Officers will become much more detailed when the communication diagram is drawn. The conversations between the actors can be formalized. As mentioned previously, several communication diagrams can be drawn to represent the New Tour Record scenario. These communication diagrams are useful in discovering all the classes and pertinent objects. Once the classes are identified, it becomes easier to understand and deduce associations.  

Decisions Made While Drawing the Analysis Class Diagram

c). Write a brief summary of the decisions made whilst drawing the diagram, and your reasons for making them.

• Control objects
• Entity Objects
• Boundary Objects

• Clerical Assistant gets details of tours from administrative staff.
• Clerical Assistant checks if the tour exists in the database before entering details.
• The system screens error messages if the clerical assistant enters incorrect data.
• The clerical assistant discusses about the tour with financial officers before entering them into the system.

• Clerical Assistant
• Financial Officer/Branch Manager
• System DB
• Driver and Tour Leaders

• Adding new Tour records into the system
• Modifying tour records in the system
• Assigning tours to drivers through the system (in most cases the tour leaders should be notified of the assignment too)
• Assigning multiple drivers to the new tour records (this is a recursive call in the communication link diagram. The call happens till all drivers are assigned with tours)
• System checks if valid tour information is entered into the system.

a). In your own words, briefly describe what is modelled in a Sequence Diagram, and how Sequence Diagrams can be useful in systems analysis and design 

The sequence diagram is used to show timely interactions between various objects. The interactions are showcased in sequential order. Unlike class diagrams where the sequence is an exclusive factor, the sequence diagrams depend on the order of interactions. It helps in understanding how businesses communicate with one another. It gives a clear picture of how various objects engage in lively interactions. Apart from using sequence diagrams to document the organization’s current functionalities, the sequence diagrams can be used at business level. These diagrams are useful in identifying the way future system implementations can be done. During the phase of requirements gathering, system analysts work on use cases and provide better levels of refinement. The use cases or scenarios can be refined into several sequence diagrams. All use cases don’t have to be presented in a single sequence diagram. e sequence diagram for “Record New Tours” the organization’s technical staff (including the clerical assistant) will be able to document the future behavior of the system. During various stages of system development and design, both developers and architects will be able to use the diagram and force details about object interactions. This is a way of fleshing the entire system design. By default, the sequence diagram helps in transiting requirements from various user scenarios to formal details. 

The “Record New Tours” is a use case scenario that can be broken into the following sequence diagrams:

• Use case scenario when a single driver is associated to a tour
• Use case scenario when multiple drivers are associated to a tour
• Use case scenario when the tour details are existing in the system
• Use case scenario when details must be gathered from the administrative staff, financial officers (or branch managers) and tour leaders.
• Use case scenario when invalid details are entered into the system

• Clerical assistant
• Financial Officer (branch manager)
• System Database 

b). Draw a Sequence Diagram for the use case ‘Record New Tour’. This should include all control, boundary and entity objects involved in the scenario and the sequence of interactions that take place in order to meet the system requirements. Your diagram should be drawn using the Enterprise Architect software, and copied and inserted as a picture into your document. 

c). Write a brief summary of the decisions made whilst drawing the diagram, and your reasons for making them. 

• The Clerical Assistant initiates the process of adding a new tour into the system
• The system has a user interface with all fields that must be entered by the clerical assistant.
• The system initiates the process of assigning drivers to the tour.
• The clerical Assistant has the freedom to decide if a single driver or multiple drivers should be assigned to the tour.
• The system allows the clerical assistant to enter multiple tours in the database.
• The system is responsible for displaying error messages when incorrect record details are entered. The clerical assistant doesn’t have to be concerned about them.

Modeling tools are powerful and capable of improving the quality of your system analysis and design process. With the right CASE Tools, you can translate requirements into high quality systems. Companies should use Modeling tools iteratively during analysis and design. This way, a better understand between the IT and business team can be achieved. The UML tools help with understanding processes and system requirements that should be met. 

What is Modelled in a Communication Diagram and How it is Useful

During the initial stages, UML tools help in identifying the overall objectives of the system. These objectives can be validated against requirements through CASE tools and use case analysis. The actors and initial use cases must be identified as a part of the first-and-foremost iteration. In the subsequent iterations, the system has to be refined further. This involves the development of use case scenarios, sequence diagrams, collaboration diagrams, class diagrams and statechart diagrams. With every iteration, the system gets a much more detailed look. 

Once system analysis comes to an end, you will have an accurate list of activities, classes, sequencing and scenarios. Results from CASE Models help in relating to the thoroughness of system analysis and design. It will reduce the time required to develop a high quality product. The ultimate idea of using “Computer Aided Software Engineering (CASE)” technology is to improve the developer’s productivity by offering a collection of labor-saving and well-integrated tools.

Here are few reasons why analysts and designers should use CASE tools during the software development lifecycle:

CASE Tools are useful in improving the speed of various tasks in the software development life cycle. You will have the time to accomplish plenty of tasks. This includes tasks with specifications and diagrams. According to studies, CASE Tools have improved productivity by 120 to 300% in many organizations.

CASE Tools and UML modeling methods can increase accuracy. These tools offer an edgy way of error checking and debugging. It is important to spot and remove defects at an earlier point of time. Indeed, CASE Tools are useful in shaping modern software solutions. (early defect removal is very important in the SDLC. When corrections are made during the design stage, modifications will become easier as the system grows).

CASE Tools can reduce the overall maintenance lifetime. This is a result of automatic code generation, better analysis and better designs. Additionally, the tools help with better documentation too. This is how companies reduce the overall cost and effort required during maintenance. CASE offers a wide range of re-engineering tools too. These tools can be used to make processes quicker, efficient and cheaper.

CASE Tools and UML Models focus on object oriented technologies. These technologies help in developing better programs. With lower CASE Tools, it is possible to develop applications from the very first design & analysis phase.

Software programs developed with the help of CASE Tools offers better user participation levels. This improves the rate at which new systems are accepted. Additionally, it reduces the overall learning curve for developers. 

On the whole, companies like “World Wide Tour Management System” should use CASE Tools and UML Modeling methods during software development. These tools help with information handling and a better understanding of the solution. It makes it easier to know and position stakeholders at a better level. Also, system analysis and designers will be able to break all the operations into small, handle able ones. 

References 

Booch, G., J. Rumbaugh and Jacobson, I. The Unified Modeling Language User Guide, 2^nd, Boston, U.S. Addison-Wesley, 2005

Fowler, M. UML Distilled: A Brief Guide to the Standard Object Modeling Language, 3^rd, Boston, U.S. Addison-Wesley Professional, 2003

Booch, G., J. Rumbaugh and Jacobson, I. The Unified Modeling Language User Guide, 2^nd, Boston, U.S. Addison-Wesley, 2005

Dennis, A. Systems Analysis and Design, 5^th, Hoboken, NJ, John Wiley & Sons, 2012

Alhir, S. S. UML in a Nutshell, U.S., O'Reilly Media, Inc., 1998.

Williams, L. A Survey of Agile Development Methodologies,   https://agile.csc.ncsu.edu/SEMaterials/UMLOverview.pdf (accessed 3 August 2017)

Booch, G. et al. Object –Oriented Analysis and Design with Applications, 3^rd, Boston, U.S. Addison-Wesley Professional, 2007

Necco, C., N. Tsai and S. Chang. The Impacts and Benefits of Using CASE Tools in the System Development Life Cycle. Journal of International Information Management, 3, no. 1, 1994, pp. 67-77

Baik, J., and B. Boehm. Empirical Analysis of CASE Tool Effects on Software Development Effort.  https://sunset.usc.edu/TECHRPTS/2000/usccse2000-504/usccse2000-504.pdf (accessed 3 August 2017)