Business Modeling and Analysis

Business Modeling and Analysis

REQUIREMENT

ANALYSIS

DESIGN

IMPLEMENTATIONTEST

Purpose of requirements workflow

Aim development toward the right systemOther workflows focus on building the system right

Describe what the system should and should not doan agreement between customer (including user) and development

organizationin the language of the customer/user

TasksList candidate requirementsUnderstand system contextCapture functional requirementsCapture non-functional requirementsValidate requirements (not well-developed in RUP)

Starting points

SystemRequirements

Detailed customer requirements document

Business model

Domain object model

Vision statement

Similar systems

Vague Overly Detailed

List candidate requirements Feature list

Candidate features that could become requirementsgood ideas added to feature listfeatures taken off list when they become formal requirements

Planning values: status, cost, priority, risk

Understand system context Business or domain model

Domain modelIdentify and name important concepts and entities in the

system contextIdentify and name relations between domain objectsGlossary for now, possible classes in analysis and design

workflows

Business modelDomain (object) model plus

processes/behaviors workers, their responsibilities and operations

Decide whether to build a business model, a domain model, or simply a glossary of terms

Capture functional requirements Use cases

Capture requirements as use casesUse case: a user’s way of using the systemWhen an actor (user or external subsystem) uses the system,

the system performs a use caseAll use cases = all the things the system must do

Capture user interfaces that support the use cases

Capture non-functional requirements Supplementary requirementsand use cases

System propertiesenvironmental or implementation constraints

e.g. must have remote access or must run on Linux or WinNT

“-ilities”: performance, reliability, security, maintainability, extensibility, usability, etc.

Tie to use cases or domain concepts, where possiblethose that cannot be tied (they are general) are listed as suppleme

ntary requirements

Requirements in the life cycle phases

Inceptionidentify most of the use cases to define scopedetail critical use cases (10%)

Elaborationdetail the use cases (80% of the requirements)

Constructionidentify and detail remaining use cases

Transitiontrack and capture requirements changes

Domain modeling

Objects or concepts: things in the system context that the system must manipulate or keep track of

Events that transpire in the system contextCapture as UML class diagrams or (for small

systems) as a glossary of termsCreates a common language for customer and

developerFocus on domain modeling; defer system internal

modeling to analysis, design, and implementation

Business modeling

“Business:” the working context of the system, even if it is not a business application

Business use case modelprocesses (use cases) and users (actors) in rolesrepresents system from a usage perspective and outlines how it provides

value to its users

Business object modelhow each use case is realized by a set of workers who are using business

entities and work unitscapture as UML class diagrams (as in domain modeling), interaction

diagrams and activity diagramsalso capture business rules and constraintsmay use UML business stereotypes (see Fig. 6.4 p. 124)

Requirements definition/specificationRequirements definition

A statement in natural language plus diagrams of the services the system provides and its operational constraints. Written for customers

Requirements specificationA structured document setting out detailed descriptions of the

system services. Written as a contract between client and contractor

Software specificationA detailed software description which can serve as a basis for

a design or implementation. Written for developers

Iterations of one documentor

“Waterfall” series of documents

Business Engineering

Business engineering delivers models as a chart for the futureSimilar artifacts are delivered as those for a

software system. Main difference is that the ‘system’ being modeled is now a business organization instead of a software system.

An OO business engineering project results in the implementation of a new organization defined by business actors, business use cases, worker types, business entity object types(work products) and competence units (organizational group of workers)

Business ModelsBusiness modeling is a technique to help answer

critical questions, such as:How do you know you have identified all system use

cases?What do the workers (users) do before using our

system?What business value does the system bring?What is the business system this computer system

will be supporting?

Packaging

Business model

Order entry

finance

manufacturing

The Business Object Model DescriptionThe Business Object Model work product identifies objects of importance

to a business and documents the relationships between them in terms of responsibilities and behavior.

Its emphasizes the roles performed in the business area and their active responsibilities. It uses a subset of notation from the Unified Modeling Language (UML).

The Business Object Model brings the notions of structure and behavior together.

It is a bridging work product that articulates business concerns in a way that is similar to methods of software development while retaining a purely business content.

It is a consolidation of what is known about the area of business concern expressed in terms of objects, attributes, and responsibilities.

A Business Object Model is not a “model of business objects.” It is an “object model of the business.”

The difference is a matter of perspective. The term “business objects” connotes the part of a software solution that directly

represents items of interest to business. The software domain is associated with the scope of a planned implementation. This implementation-free view of the software space is the subject of an analysis object

model

The Business Object Model Purpose

The Business Object Model is positioned firmly on the bridge between the world of business and the world of information systems development.

It explores the essence of business area knowledge in a way that provides a transition from thinking about business issues to thinking about software applications.

Its creation is a way of verifying requirements to be enabled or supported by the information system to be built.

Agreement between business object definitions and relationships, and the names for the objects and relationships permits business area knowledge to be represented in a precise manner that can be understood and validated by business area experts.

In addition, the Business Object Model Helps to scope what is inside and outside the specific application being developed. The boundaries of the application are explored through an object view of the business area. Can be reused by many development projects.

To the extent that it is it free of design details and is also free of application boundaries, a good Business Object Model is a key asset that a company can build, maintain, and reuse in many applications within the business area

Business Object Model

A Business Object Model is complete when it reflects all important business concepts within the intended scope as specified by the classified business terms.

A quality Business Object Model is one in which:The names of object types accurately reflect either concepts in the business area

or abstractions that structure the model. Class names are appropriate. Names should convey intent. Be suspicious of

names such as Controller and Manager as these often indicate a centralization of control.

No design artifacts are present.

This is a simplified drawing as it is intended to convey business information in a way that is conducive to thoughts of objects collaborating in a software space. There are some structural relationships, but the thrust of the drawing is to convey behavior between the role objects and others.

Gift Registry - Business Object Model

*

1..*WishLister

Product

Clothing HousewaresProductOption

CustomerDefiner

EventCoordinator

ProductSelector

WishList

WishListItem

InterStoreCommunicator

**

** Complements

IsAlternativeFor1

Creates

RequestsBroadcast AccessesToTransmit

CustomerAddress

BeforeEventAddress

AfterEventAddress

Event

CustomerGuestLocation Store

BroadcastsTo

MatchesRequirement

GathersToTransmit

CustomerRecordCommunicatesAt

Authenticates

ClothingSizes ClothingColors

Establishes RequestsCreation

ProvidesShippingRadius

Adds

RequestsAuthenticationShipToBefore ShipToAfter ProvidesRequirements ConveysSelection

RegistersGifts

EnsuresCompleteness

*

11

Establishes

1

1

1

0..1

1

* *

The following example is based on a business process model from a retail store gift registry process. This is a view on a more comprehensive model of the retail store operation. There are various roles that have been defined in the gift registry process, and these are reflected in the model below as active object types, such as EventCoordinator, WishLister, CustomerDefiner, and ProductSelector. These are shown at the center of the view, collaborating to ensure that the customer is defined, the WishList is created, Products are selected and associated witWishListItems, etc

Gift Registry - Business Object Model

*

1..*WishLister

Product

Clothing HousewaresProductOption

CustomerDefiner

EventCoordinator

ProductSelector

WishList

WishListItem

InterStoreCommunicator

**

** Complements

IsAlternativeFor1

Creates

RequestsBroadcast AccessesToTransmit

CustomerAddress

BeforeEventAddress

AfterEventAddress

Event

CustomerGuestLocation Store

BroadcastsTo

MatchesRequirement

GathersToTransmit

CustomerRecordCommunicatesAt

Authenticates

ClothingSizes ClothingColors

Establishes RequestsCreation

ProvidesShippingRadius

Adds

RequestsAuthenticationShipToBefore ShipToAfter ProvidesRequirements ConveysSelection

RegistersGifts

EnsuresCompleteness

*

11

Establishes

1

1

1

0..1

1

* *

UMLThe UML provides different diagrams. Each UML diagram provides a

different view of the business:use case diagrams describe the business context.activity diagrams describe behaviors in the business, or business

workflows.class diagrams describe the static structure in the business.interactions diagrams (sequence diagrams and collaboration

diagrams) describe the dynamic interactions between employees and things that they manipulate. Thus they indicate how the behaviors described in activity diagrams are realized.

Business Modeling with the UML

The Use Case ModelUse case model

Actors and use casesUse cases represent processes

Accept customer orderAllow a customer to order

Actors represent agents impacting the processCustomerEmployeeVendor

IntroductionMajor effort in requirements :

Develop a Model of the System to be built.Employ usecases to build such a model.

Functional Reqs are structured as usecases. Non Functional Requirements are specific to a

single usecase.Remaining Non-Functional requirements are kept in

a separate document called the supplementary requirements.

Importance of UsecaseOffers a systematic and intuitive way to capture the

functional requirements.By using usecases the analysts are forced to think in

terms of who users are and what business or mission needs can be fulfilled through them.

It drives the entire development process.

The Requirements Workflow

The artifacts created in the requirements workflow.The workers participating in the requirements

workflow.The requirements capture workflow, including each

activity in more details

ArtifactsUse Case ModelActorsUse cases

Flow of EventsSpecial Requirements

Architecture Description Glossary

The Use Case Model

* *

1

Use Case Model

Use Case System

Actor Use Case

Artifact - The Use Case ModelAgreement on requirements between developers and

customers, i.e, the condition or capability to which the system must conform..

Provides essential input for analysis, design and testing.A use-case model is the model of the system containing

actors and their usecases and their relationships.For large number of usecases in a system, packages may be

introduced in the model to manage its size.Presents Model in diagrams that presents the actor and

usecases from different viewpoint and different purpose.

Artifact - ActorParties outside the system that collaborate with the systemOften corresponds to workers in a business.An actor plays one role for each case with it collaborates.

Each time a specific user interacts with the system, the corresponding actor instance is playing the role.

An instance of an actor is thus a specific user interacting with the system.

Any entity that conforms to an actor can act as an instance of the actor.

Artifact - ActorActors are not a part of the system.Anyone or anything that must interact with the system.An Actor may

Only input information to the system.Only receive information from the system.Input & receive information to and from the

system.

Artifact - Identifying Actors Typically found in the problem statement.Conversation with the customers or Domain Experts.By asking the following questions :

Who is interested in a certain requirement?Where in the organization is the system used?Who will benefit from the use of the system?Who will supply, use and remove the information from the system?Who will support and maintain the system.Does the system use an external resource.Does one person play several different roles?Do several people play the same role.Does the system interact with a legacy system?

Artifact - UsecaseEach way a actor uses the system is represented as a

usecase.Are “chunks” of functionality that the system offers

to add a result of value to its actors.Sequence of actions, including alternatives of the

sequence, that the system can perform, interacting with actors of the system.

Specification of the behavior of the dynamics of the system.

Artifact - UsecaseUsecase is a classifier – It has attributes and

operations.Usecase description include the following:

State Chart Diagrams Activity Diagrams Collaboration Diagrams Sequence Diagrams.

Usecase InstanceExecution of usecase.Interacts with the actor instance and performs a

sequence of actions as specified by the usecase.This sequence is specified by a state chart or activity

diagram..Many paths are possible through a usecase and many

are very similar. These are the alternatives through the Usecase.

Path in a usecasePath through a use case looks as follows:The Use-Case is instantiated and put in a start state.Invoked by external message from actor.It transitions to another state by performing a sequence of

actions. Such a sequence contains internal computations, selection of path and message output.

It awaits, in its new state, another message from an actor.It is invoked again by a new message and so on.It goes over many states until the usecase is terminated.

Usecase instance - CharacteristicsHave attributes that is manipulated during usecase execution.Usecase instance is atomic.A Usecase instance does not interact with other instances.The only interaction that happens in a Usecase is between Actor

instances & Usecase instances.The interference issues between different uses of a system is

resolved in the Analysis and design phase when we realize these usecases as collaboration classes and subsystems.

Usecases - Flow of EventsDescribes what the system does when a specified usecase is

performed.Also specifies how the system interacts with actors when the usecase

is performed.Flow of events for each usecase can be captured as a separate textual

description of the use-case's sequence of action.Description includes a set of sequence of actions that are suitable to

modify, review, design, implement and test together and to describe as a section or subsection in the user manual.

Usecase – Special Reqmnts.Textual description that collects all requirements on

a usecase.Primarily non-functional requirements that are

related to the usecase and that are needed to be handled in subsequent workflows such as analysis, design or implementation.

Usecase – How to identify?

The following question may be used to help identify the usecases of the system.

What are the task of each actor?Will any actor create, store, change, remove or read values from the

system?What usecases will create, store, change, remove or read values

from the system.Will any actor need to be informed of certain occurrences in the

system?Will any actor need to inform the system of any external

occurrences? What usecases will support and maintain the system?Can all functional requirements be performed by the usecases?

Artifact - Architectural Description

Architectural View of the usecase model depicting the architecturally significant usecases.

Should contain all usecases that describe some important and critical functionality or that involves certain requirements that must be developed early in the software cycle.

This view is used as an input when the usecases are prioritized to be developed within an iteration.

Artifact - GlossaryUsed to define important and common terms. Used by the

analysts when they describe the system.Is useful in reaching a consensus among developers regarding

the definition of various concepts and notations to reduce the risk of misunderstandings in general.

Can often be derived from a business model or domain model, but because it is less formal it is easier to maintain and more intuitive to discuss with users and customers.

Tends to be more focused on the system to be built instead of system’s context.

Artifact – User Interface PrototypeHelps during requirements capture to understand and

specify the interaction between human actors and system.

Helps us in developing a better user interface and to understand usecases better.

Workers – System analyst

Usecase Model Actor Glossary

System Analyst

Workers – Usecase specifier

Use Cases

Usecase Specifier

Workers – User Interface Designer

User Interface Prototype

User Interface Designer

Workers – Architect

Architecture Description

Architect

Usecase Model

Architectural View

WORKFLOWA Sequence of activities which are ordered so that

one activity produced output that is used as an input for the next activity.

When workers perform activities they create and modify artifacts.

An activity may be revisited several times and each visit may entail carrying out only a fraction of the activity.

Workflow – SequencePerform Find Actors and usecases.Find architecturally significant usecases to provide

input to the prioritization of usecases to be developed in the current iteration.

Detail the usecases.Suggest suitable user interface for each actor based

on the usecases.

Find Actors & Usecases - WhyDelimit our system from its environment.Outline who and what will interact with the system

and what functionality is expected from the system.

Capture and define a glossary of common terms that are essential for creating a detailed description of the system’s functionality.

Find Actors & Usecases - ActivityFinding the actorsFinding the usecasesBriefly describing the usecaseDescribing the usecase model as a whole.

The above steps are performed concurrently.

Find Actors & Usecases - Activity

Business Model

System Analyst

Supplementary Requirements

Feature List

Use-Case Model

[Outlined]

Glossary

Find Actors and Use Cases

Find Actors and Usecases - Example

Briefly describing each usecase

Identify the usecases and explain them in a few words.

Later describe each usecase briefly in a few sentences.

Later a step by step description of what the system needs to do when interacting with its actors.

Refer to Page 150 of the book for an Example.

Describing the usecase model as a whole

Prepare diagrams and descriptions to explain the use case model as a whole, particularly how the usecase relate to each other and the actors.

To ensure consistency while describing several usecases concurrently, it is practical to develop some glossary of terms.

Terms are derived from classes in domain or business model.

Refer to Page 151 of the book for an Example.

Prioritizing UsecasesDetermine which one needs to be developed in

earlier iterations and which can be developed in later iterations.

The results are captured in architectural view of the usecase model.

Prioritizing Usecases

Business Model

Architect


Feature List

Architectural Description view of the

usecase modelPrioritizing

Detailing a UsecaseDescribe flow of events in details including how the

usecase starts, ends and interacts with actors.With usecase model and associated usecase diagrams

as starting point, the individual usecase specifiers can now describe each usecase in details.

Detail the step-by-step description of each usecase into a precise specification of the sequence of actions.

Detailing a UsecaseHow to structure the description to specify all the

alternative paths to the usecase.What to include in a usecase description.How to formalize the use-case description when

necessary.

Detailing a Usecase

Use-Case Specifier


Use Case [Detailed]

Detail a Usecase

Use-Case Model

Glossary

Structuring a Usecase Desc.Defines the state that use-case instances may enter

and possible transition between those states.Each such transition is a sequence of actions that are

performed by a usecase instance when triggered by an event such as a Message.

Artifact – State Transition Diagram.

What to include in Usecase Desc.Start State as Pre-conditionHow and When the use-case startsRequired order in which order must be performed.How and when the usecase ends.Post Conditions or End States.Paths of execution that are not allowed.Alternative Paths.System Interaction with the actors and what they exchange.Usage of objects, values and resources in the system.Describe what the system & actors do.

Formalizing the Usecase DescWhen describing a usecase, ensure that we cover all

possible cases.When usecases become very complex, a structured

description technique may be needed.

State ChartsActivity DiagramsInteraction Diagrams

Prototype User InterfaceBuild a prototype of the User Interface.Start with a use case and try to discern what is needed from th

e user interfaces to enable usecases for each actor (Logical User-Interface Design).

Then Create Physical User Interface design and develop prototypes that illustrates how how users can use the system to perform the usecases.

Result of this activity is a set of user-interface sketches and user-interface prototypes that specify the look and feel of the user Interface for actors.

Structuring Use Case ModelTo Extract general and shared descriptions of

functionality that can be used by more specific use-case descriptions.

Extract additional and optional description of functionality that can extend more specific use-case description.

Business Modeling and Analysis

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