Chapter 5 Practice: A Generic View

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Chapter 5Practice A Generic View
Software Engineering A Practitioners Approach,
6th edition by Roger S. Pressman
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What is Practice?

• Practice consists of the
• concepts
• principles
• methods
• tools
• that must be considered as software is planned
  and developed.
• It represents the detailsthe how-tosof the
  software process.

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The Essence of Practice

• George Polya, in a book written in 1945 (!),
  describes the essence of software engineering
  practice
• Understand the problem (communication and
  analysis).
• Plan a solution (modeling and software design).
• Carry out the plan (code generation).
• Examine the result for accuracy (testing and
  quality assurance).
• At its core, good practice is common-sense
  problem solving

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Core Software Engineering Principles

1. Provide Value to Your Users
2. KIS (Keep It Simple)
3. Maintain the Vision
4. What You Produce, Others Will Consume
5. Be Open to the Future
6. Plan Ahead for Reuse
7. Think before You Do

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Software Engineering Practices

• Consider the generic process framework
• Communication
• Planning
• Modeling
• Analysis Modeling
• Design Modeling
• Construction
• Coding
• Testing
• Deployment

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Communication Practices

• Principles
• Listen effectively
• Prepare before you communicate
• Someone should facilitate the activity
• Face-to-face communication is best
• Take notes and document decisions
• Strive for collaboration
• Stay focused, modularize your discussion
• If something is unclear, draw a picture
• Know when to move on
• Negotiation works best when both parties win.

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Planning Practices

• Principles
• Understand the project scope
• Involve the customer in planning
• Recognize that planning is iterative
• Estimate based on what you know
• Consider risk as you define the plan
• Be realistic
• Adjust granularity as you define the plan
• Define how you intend to ensure quality
• Describe how you intend to accommodate changes
• Track the plan frequently and make necessary
  adjustments

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Planning Practices

• Bohems W5HH Organizing Principle. Answers to the
  following questions lead to the project plan
• Why is the system begin developed?
• What will be done?
• When will it be accomplished?
• Who is responsible?
• Where are they located (organizationally)?
• How will the job be done technically and
  managerially?
• How much of each resource is needed?

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Modeling Practices

• Analysis modeling principles
• Represent the information domain
• Represent software functions
• Represent software behavior
• Partition these representations
• Move from essence toward implementation

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Modeling Practices

• Design Modeling Principles
• Design must be traceable to the analysis model
• Always consider architecture
• Focus on the design of data
• Interfaces (both user and internal) must be
  designed
• User interface should consider the user first
• Components should exhibit functional independence
• Components should be loosely coupled
• Design representations should be easily
  understood
• The design model should be developed iteratively

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Modeling Practices

• Agile Modeling Principles Ambler 2002
• The primary goal is to create software, not build
  models
• Dont create more models than you need
• Produce the simplest model that will describe the
  problem
• Build models that are easy to change
• Be able to state an explicit purpose for each
  model
• Adapt the models you develop to the system at
  hand
• Build useful models, not perfect ones
• Focus on the what the model communicates, not its
  syntax
• If you are uncomfortable with a model,
  somethings probably wrong
• Get feedback as soon as you can

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Construction Practices

• Coding Principles
• Preparation. Before you write one line of code,
  be sure you
• Understand of the problem youre trying to solve
• Understand basic design principles and concepts.
• Pick an appropriate programming language.
• Select an appropriate programming environment and
  tools.
• Create unit tests for each component you plan to
  create.

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Construction Practices

• Coding Principles
• Coding. As you begin writing code, be sure you
• Follow structured programming BOH00 practice.
• Select data structures that will meet the needs
  of the design.
• Create interfaces consistent with the software
  architecture.
• Keep conditional logic as simple as possible.
• Create nested loops in a way that makes them
  easily testable.
• Select meaningful variable names and follow other
  local coding standards.
• Write code that is self-documenting.
• Create a visual layout that aids understanding.

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Construction Practices

• Coding Principles
• Validation. After youve completed the first
  pass, be sure you
• Conduct a code walkthrough when appropriate.
• Perform unit tests and correct errors youve
  uncovered.
• Refactor the code.

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Construction Practices

• Testing Principles
• All tests should be traceable to requirements
• Tests should be planned
• The Pareto Principle applies to testing
• Testing begins in the small and moves toward
  in the large
• Exhaustive testing is not possible
• Note A successful test is one that uncovers an
  as-yet-undiscovered error.

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Deployment Practices

• Principles
• Manage customer expectations for each increment
• A complete delivery package should be assembled
  and tested
• A support regime should be established
• Instructional materials must be provided to
  end-users
• Buggy software should be fixed first, delivered
  later