2 3 moving from blastoff to writing requirements: understanding the work

Lecture 5Ch. 4: Business Use Cases

SE3821 Software Requirements and SpecificationDr. Rob Hasker (based on slides by Dr. Brad Dennis)

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Today’s Outline• Business Events• Business Use Cases• Product Use Cases• Actors• Use Case Diagrams

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The Volere Process

• Moving from blastoff to writing requirements: understanding the work

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What are business events?• A thing that happens that makes your business respond in some way.• They can happen the moment an adjacent system

decides to do something (inbound).• They can happen when some processing condition

occurs (outbound). • They can happen on some schedule (time-

triggered).• They have inputs, outputs, and often both.

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Styleup Business Events

The work of tailoring weather

appropriate fashion advice.

Weather Forecast Service

Advertisers

Fashion Advisors

CustomerSubscribes

Profile

Fashionrecommendation

Weather

Places ads

Ad data

Fashion advice

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Styleup Business Event Table

Business Event Input Output

Customer subscribes Name and credit card Receipt

Customer adds profile

Customer meta data Confirmation

Weather forecast Forecast data

Advertiser places ads Ad content Acknowledgement

Ad data Report

Fashion advisor advises

Fashion advice

Work sends recommendation

Fashion advice

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How do we respond to Business Events?• This is the Business Use Case (BUC).• You should consider what the work does and what the

adjacent system wants or needs.

Customer

Advising

Stored DataReportin

g

Stored Data

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How do we respond to Business Events?• This is the Business Use Case (BUC).• You should consider what the work does and what the

adjacent system wants or needs.

Customer

Advising

Stored DataReportin

g

Stored Data

work boundary

the work

adjacent system/user/client

event

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What are some advantages of BUCs?• A BUC is a whole, self-contained response.

• It only interacts with other BUC’s via stored data.

• This provides a nice, cohesive way to begin to partition the work.• They are chunks of work that are recognizable to stakeholders.• A BUC happens in a discrete time frame.

• Once triggered, it runs to completion.

• It may aid in identifying more stakeholders, such as SME’s.• We’ve made no assumptions about the product.

• We are modeling what the work is and not missing potentially important aspects.

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Business Use Case Exercise

• Regroup with your partners from Lab 1• Spend the next 10 minutes and model one Business Use

Case for a Business Event from your earlier exercise.

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What’s a product use case?• The portion of the BUC that the product will handle.

Consider a scope that best contributes to the BUC work.

Customer

Advising

Stored DataReportin

g

Stored Data

The PUC

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Why not just focus on the product?• Why do we have business use cases, product use

cases?• Key issue: identifying a useful scope• Focus on product: key issues in ripping music from CD are

formats, bit rates, letting user name the song• But consumer interested in building a music collection

• Important tool: stepping back• Examine scope, look for broader needs

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How does this map to a use case diagram?• A use case is a chunk of functionality that describes

the interaction between a user and a system.

Customer

Advising

Stored DataReportin

g

Stored Data

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How does this map to a use case diagram?• A use case is a chunk of functionality that describes

the interaction between a user and a system.

Customer

Advising

Stored DataReportin

g

Stored Data

Use case diagram

Actors

An actor is person or system that interacts with the system under development.

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UML Use Case Diagrams• UML Use Case Elements

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Styleup-Advisor PUC Diagram

Generate Fashion Advice

Reporter

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Styleup BUC?• UML Use Case Diagram doesn’t have notation for a

data store, so it isn’t suitable for modeling a BUC. BPMN 2.0 is a feature rich language.

Fashion AdviceStart

Evaluate profile and forecast and

generate advice

Profiles, forecasts, advice

advice ready Reporting Process

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Group Exercise

• Regroup with your partners from Lab 1• For the remainder of the class produce a Business Event

table for your Lab 1 scenario. Select one business event and model a BUC. For some portion of that BUC, develop a PUC. You may use the Work Context Diagram generated in Lecture 4. Be prepared to share highlights of the exercise.

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Next Meeting• Lecture 6 – Investigating the Work• Read Chapter 5