From Business To System Use Cases

1
From Business To System Use Cases

• Presented by
• Leslie Munday

2
Agenda/Contents

• The purpose of this presentation is to give an
  overview of the connection between the Business
  Modeling, Enterprise Architecture and
  Requirements disciplines of the PRC Dev Case.
• In the next two hours we will cover
• Business Use Cases (BUCs)
• Traceability From BUCs To Stakeholder
  Requirements
• Allocation Of Business Activities
• Candidate System Use Cases (CSUCs)
• Traceability From CSUCs To BUCs
• System Use Cases (SUCs)
• Traceability From SUCs To BUCs

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Intended Audience

• This presentation will demonstrate how AWS
  relates business use cases to system use cases.
• At the end of this presentation you will
  understand how to
• allocate business activity to systems
• create a candidate system use case model
• manage traceability between BUCs and SUCs.

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Prerequisites

• In order to fully understand this presentation
  you should have previous experience with
• Business use case modeling.
• System use case modeling.
• Modeling with Rational Rose.
• Managing traceability with RequisitePro.

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Use Cases Revisited

• What is a Use Case
• Primary actor - Initiates the use case
• Secondary actors - Interfaces with the use case
• Precondition - The state immediately before the
  use case begins
• Basic flow step - A required step in the use case
  flow
• Alternative flow step - An unexpected step in the
  use case flow
• Postcondition(s) - A state immediately after the
  use case completes.

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Types Of Use Case

• Business(BUC) Describes a story involving the
  interaction of people and the things they are
  manipulating or using.
• System(SUC)
• Describes a story of an interaction between an
  actor (could be a person or a machine) and the
  system being constructed.
• System use cases are the result of a desire to
  automate parts of business use case.
• Candidate System Use Case(CSUC)
• An allocation of a BUC step to a SUC.

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Rose-ReqPro Association

• Associate package to project.
• Disassociate package from Project.

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Use CaseReqPro Association

• New Create item in ReqPro.
• Associate Link to ReqPro item.
• Open Display associated ReqPro item.
• Disassociate Unlink from associated ReqPro item.

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Use Case-ReqPro Commands

• Requirement Properties ? New - Creates an
  associated ReqPro requirement of the appropriate
  type (SUC or BUC).
• Use Case Document ? New Creates a use case
  specification of the appropriate type (SUC or
  BUC) and creates an associated ReqPro
  requirement.
• Requirement Properties ? Associate Links the
  use case to a ReqPro requirement.
• Use Case Document ? Associate - Links the use
  case to a ReqPro to a Specification.
• View RequisitePro Association Shows you which
  project this use case is linked to.

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Traceability Tree

• Shows how Stakeholder Requests are realized by
  Business Use Cases.

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Activity Diagrams

• Describe the steps in a use case, as activities
  connected by transitions.
• Show alternate flows, as transitions leaving
  decision boxes.
• Show parallel activities with synchronization
  bars.
• Indicate the preconditions to the use case, as a
  start state.
• Indicate postconditions of the use case, as end
  states.
• Show who performs the business activities, and
  what systems they are allocated to by placing
  activities in swimlanes.
• (Optionally) Defines objects that are produced
  and consumed by activities.

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BUC Diagram
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A BUC Activity Diagram
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A System Use Case Diagram
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What Is The Connection?

• Steps in a BUC must be realized by a SUC,
  otherwise they are manual activities.
• The SUC automates steps in a BUC in an order to
  reduce
• manual effort.
• the risk of making mistakes.
• duplication of work.
• other factors (cost, speed, etc).

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Swimlanes In Business Activity Diagrams

• Swimlanes allow the activities in the BUC to be
  allocated to actors.
• Actors may be people or systems.
• Add a swimlane for each actor, worker and
  potential system that will perform and activity.
• Place the activity in its appropriate swimlane.

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Swimlane Example
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Linking BUCs And SUCs

• Create a requirement specification in ReqPro for
  the BUC.
• Create a requirement in ReqPro for the SUC.
• Open the properties window for the SUC and add a
  Trace From BUC link.
• OR
• Open the properties window for the BUC and add
  Trace To SUC link.
• A BUC will have many SUC links. A SUC may have
  many BUC links.

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Create Requirements For Steps

• Each activity in the BUC has an equivalent step
  in the BUC specification.
• Each step in the BUC specification is associated
  with an equivalent requirement in the ReqPro BUC
  package.
• Each activity is labeled with the identifier
  given by ReqPro to the equivalent requirement.

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ReqPro BUC Steps
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Activity Diagram With Identifiers
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Traceability Report Between BUC Steps and BUC
activities
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Candidate System Use Cases

• Are how we get from BUCs to SUCs in Rational
  Rose.
• In the Candidate System Use Case Package, a CSUC
  exists for each activity in the BUC activity
  diagram.
• The CSUC is given the same name as the activity
  (including identifier).
• The CSUC is not linked to the BUC Activity, so we
  use a SoDA report to check consistency.
• Using the trace to link in the CSUC requirement,
  the CSUC is linked to the actual SUCs.)

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Business Allocation Diagram

• Shows activities allocated to candidate systems

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CSUC Diagram

• Shows CSUCs Traced to the BUC

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SoDA Report Of Rose Traceability

• Return Book
• BUCS1.Requesting Patron Details gt
  BUCS1.Requesting Patron Details
• Traceability to Return Book found.
• BUCS4.Changing Customer Record gt BUCS4.Changing
  Customer Record
• Traceability to Return Book found.
• BUCS6.Filing Customer Record gt CS6.Filing
  Customer Record
• Traceability to Return Book found.
• BUCS8.Finding Who Book Is Checked To gt No
  Candidate System Use Case found.
• BUCS9.Changing Check-Out Details gt
  BUCS9.Changing Check-Out Details
• No traceability link found.

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CSUC Diagram II

• Shows CSUCs Traced to SUCs

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BUC To SUC Traceability

• Enter the traceability links into ReqPro

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Traceability Tree
Traceability tree showing how Stakeholder Requests
are realized by System Use Cases.
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Summary

• STRs manually entered into ReqPro, or through the
  Vision document.
• BUCs entered into Rose and attached to BUC
  requirements in ReqPro.
• BUC specifications attached to BUC requirements
  in ReqPro.
• BUC requirements traced from STRs in ReqPro.
• BUC activities attached to BUC in Rose activity
  diagram.
• BUC Activities traced to BUC specification using
  a SoDA report.
• BUC activities allocated to systems in Rose BAD.
• BUC traced to CSUCs using a Rose traceability
  diagram.
• BUC activities traced to CSUCs using a SoDA
  report.
• CSUCs traced to SUCs in Rose traceability
  diagram.
• SUCs attached to SUC requirements in ReqPro.
• SUCs trace to BUCs in ReqPro.

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Traceability Overview