Unified Process versus Extreme Programming

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Unified Process versusExtreme Programming

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Outline

• Compare and contrast UP and XP
• Processes / Disciplines
• Management
• Artefacts
• Risk management some thoughts

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Unified Process
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Process Disciplines

• Requirements Specification (Kravspesifikasjon)
• System Analysis (Systemanalyse)
• Design
• Implementation
• Testing
• Deployment (iverksetting)
• Maintenance (Vedlikehold)

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Supporting Disciplines

• Configuration management
• Change management
• Environment
• Project management
• Time
• Risk
• Priorities
• Estimation
• Status Tracking / Follow up

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XP key practices

• Customer is Team Member
• User Stories
• Short Time Boxed Iterations
• Pair Programming
• Test-Driven Development
• Collective Code Ownership
• Sustainable Pace
• Open Workspace
• The Planning Game
• Simple Design
• Refactoring
• Metaphor
• (Coding standards)

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UP Disciplines vs XP Practices

• UP Disciplines
• Requirements Specification
• System Analysis
• Design
• Implementation
• Testing
• Deployment
• Configuration management
• Change management
• Environment
• Project management
• Time
• Risk
• Status tracking

• XP Practices
• Customer in Team
• User Stories
• Short Time Boxed Iterations
• Pair Programming
• Test-Driven Development
• Collective Code Ownership
• Sustainable Pace
• Open Workspace
• The Planning Game
• Simple Design
• Refactoring
• Metaphor

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Business modelling

• UP
• Processes
• Process map
• Use Cases
• Domain
• Domain model ?
• Glossary ?

• XP
• None?

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Requirements Specification

• UP
• Use Cases
• UML artefacts
• Domain model
• Dynamic models
• Non-functional requirement

• XP
• User stories
• Metaphores (?)
• UML Model schetches
• Non-functional requirements

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System Analysis

• UP
• Subtasks
• More detailed Use Case
• UML Domain model
• Prototypes?

• XP
• Subtasks
• UML model schetches
• Acceptance tests
• Working code

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Design

• UP
• UML design model
• Class
• Interaction
• Packages / Modules
• Base Architecture
• Prototypes

• XP
• UML schetches
• Simplest possible design
• Incremental code development
• Refactoring

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Implementation

• UP
• Integrated, executable code after each iteration

• XP
• Integrated, executable code after each iteration
• Test suites automatic tests

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Testing

• UP
• No particular demand for test method
• Types
• Unit tests
• Integration tests
• Acceptance tests
• (Regression testing)
• Test first can be used

• XP
• Test first
• Automatic testing
• Acceptance Testing

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Deployment

• UP
• Deployed system

• XP
• Deployed system

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Configuration Management

• UP
• Version Control
• Iteration releases

• XP
• Collective Ownership
• Refactoring
• Integrated, testable code
• Iteration releases

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Change management

• UP
• Requirements tracking
• Change requests

• XP
• Embrace change
• Planning game
• Refactoring

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Environment

• UP
• No particular demands for working environment
• Artifacts important for communication

• XP
• Pair Programming
• Test-Driven Development
• Collective Code Ownership
• Sustainable Pace
• Open Workspace

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Risk and priority

• UP
• Identify and manage risk
• High risk tasks first
• Prototypes
• Base architecture
• Prioritize use cases
• High priority first
• Use Case driven

• XP
• Identify risk
• High risk tasks early, but only if useful for
  current user stories
• Prioritize user stories
• High priority first
• User driven user in team

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Managing time

• UP
• Time boxing 2 6 weeks
• No particular method

• XP
• Time boxing 1 4 weeks
• Estimate on basis of experience - velocity
• Velocity increases

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Project management (1)

• UP
• (Release planning)
• Iteration planning
• Follow up
• Finished tasks
• Unfinished tasks
• Used time
• Remaining time
• Manager driven?

• XP
• Release planning
• Iteration planning
• Task planning
• Follow up
• Finished tasks
• Unfinished tasks
• Velocity
• Developer driven?

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Project management (2)

• UP
• Course plan for future iterations
• Detailed plan for next iteration
• Users prioritize Use Cases
• Developers estimate tasks

• XP
• Developers continuously involved in estimation
• Weekly plan stable
• Overall plan changes continuously

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Risk some thoughts

• Risk in the waterfall model
• Risk in iterative development
• Managing risk

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Risk in the waterfall model
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Risk in iterative development
R I S K
T I M E
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Risk factors (1)

• Resources
• Lack of people
• Lack of money
• Competence
• Lack of knowledge
• Misunderstanding requirements
• Missing important requirements
• Communication
• Bad coordination
• Misunderstandings
• Bad chemistry

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Risk factors (2)

• Technical risk
• Uncertain solution method
• Uncertain requirements
• Uncertain performance
• Identify uncertain subtasks
• Difficult
• Uncertain of difficult
• Uncertain extent
• Deadlines
• Illness
• Underestimated size of task
• Partners not delivering on time

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Reducing risk

• Manage risks
• Identify risks
• Assess Seriousness and Probability
• Get an idea how to handle a risk if it occurs
• Prioritize work according to risk level
• High risk tasks in early iterations
• Prototypes
• Basic functionality used by many components
• Consider high risk issues in early
  iterationsE.g. Many simultaneous users

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Discussion themes

• MDD vs XP // CASE tools vs XP
• Model is source vs Code is source
• Non-functional requirements in XP
• Have XP sufficient focus?
• Have users sufficient focus?
• Is XP downplaying software architecture?
• When is overall architecture introduced?
• Can refactoring lead to good architecture?
• Is XP too dependant on good people?
• Very little written documents need good memory
• Need helpful team members

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