Software Engineering with Reusable Components

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Software Engineeringwith Reusable Components

• RiSEs Seminars
• Sametingers book Chapters 11, 12 and 13
• Ednaldo Dilorenzo

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Summary

• Software Engineering (Chapter 11)
• Introduction
• Software Management
• Software Design
• Software Implementation
• Software Testing
• Software Maintenance
• Software Process Models (Chapter 12)
• Waterfall Model
• Exploratory Model
• Prototyping Model
• Spiral Model
• Twin Life Cycle

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Summary

• Domain Engineering
• Domain Analyses
• Domain Analyses Activities
• Domain Analyses Methods
• Foda Feature-Oritented Domain Analyses
• Domain Implementation

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Software Engineering
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Introduction
Software Engineering Chapter 11

• Cost-effective production of high-quality system
  is the primary goal of software engineering
• Software reuse and components provide crucial
  contributions in this direction
• Large software projects are broken up into
  various project phases

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Software Management
Software Engineering Chapter 11

• Software projects tend to run over budget and
  behind schedule
• Software management has to plan a project
• It comprises the following major activities
• Project planning
• Project measuring
• Project estimating
• Project scheduling
• Project controlling

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Software Specification
Software Engineering Chapter 11

• Software specifications serve as contracts
  between customers and manufacturers of software
  systems.
• For complex systems, requirements analyses may be
  necessary.
• A software specification should be complete.
• Functional and nonfunctional requirements are
  among the most important parts of a
  specification.
• Specifications should completely and consistently
  define requirements on components.

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Software Design
Software Engineering Chapter 11

• Software Design is an iterative process and
  involves describing a component at different
  levels of abstraction.
• Design includes various activities
• Architectural design
• Component or interface design
• Data structure design
• Algorithmic design

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Software Design
Software Engineering Chapter 11

• Top-down design is typical for components being
  built from scratch.
• Botton-up design proceeds in the oposite
  direction.
• Good designs are considered to have the following
  characteristics
• Modularity
• Coupling
• Cohesion
• Understandability, Adaptability

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Software Design
Software Engineering Chapter 11

• All these characteristics are related to each
  other.
• Various categories of design methods exist.
• Design methods and software reuse interact in two
  ways.

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Software Implementation
Software Engineering Chapter 11

• Implementation is the process of transforming a
  design into an executable.
• Ideally, the design of a component is independent
  of its implementation.
• We refrain from dealing with implementation in
  greater detail.

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Software Testing
Software Engineering Chapter 11

• The purpose of testing is to ascertain whether a
  component satisfies its requirements by
  discovering as many errors as possible.
• Various kinds of tests include the following
• Specification test
• Component test
• Integration test
• Acceptance test

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Software Testing
Software Engineering Chapter 11

• Various testing methods and strategies include
• Static/dynamic testing
• Black-box/white-box testing
• Top-down/botton-up testing
• With software reuse, software quality can be
  increased and testing efforts can be decreased.

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Software Maintenance
Software Engineering Chapter 11

• Software maintenance is the modification of a
  software component after its first delivery.
• Maintenance activities fall into the following
  categories
• Adaptive maintenance
• Corrective maintenance
• Perfective maintenance
• Preventive maintenance

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Software Maintenance
Software Engineering Chapter 11

• The cost of maintenance has been steadily
  increasing over the past decades.
• Reuse can have a positive influence on
  maintenance costs when high-quality components
  are available and reused for the development of
  software systems.

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Waterfall Model
Software Process Models Chapter 12

• According to the waterfall model, the software
  development process is divided in well-defined
  phases.
• The waterfall life cycle comprises the following
  steps
• Requirements analysis
• Specification
• Design
• Implementation
• Test
• Operation and Maintenance

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Waterfall Model
Software Process Models Chapter 12

• Any step might uncover problems in a previous
  step and necessitate returning and partly or even
  completely redoing earlier work.
• The waterfall model enforces a linear process,
  which implies that executable programs are
  available late in the process.
• Despite its drawbacks, the classic software life
  cycle continues to provide structure for many
  software projects.

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Exploratory Model
Software Process Models Chapter 12

• The classic software life cycle is not practical
  for many of todays software systems.
• In the exploratory model a working system is
  developed as quickly as possible.
• Large, longevous software systems are usually not
  developed by using exploratory programming.
• Exploratory software development involves
  repeatedly applying techniques.

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Exploratory Model
Software Process Models Chapter 12

• Good when both customers and developers dont
  know what they want.
• The exploratory model delivers various
  operational but incomplete products.
• Exploratory development challenge software
  engineers in that they create an open
  architecture.

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Prototyping Model
Software Process Models Chapter 12

• Rapid prototyping has become popular for the
  development of software systems with complex user
  interfaces.
• The purpose of the prototype is to enable
  customer and developer to agree on what the
  software system is supposed to do.
• Prototypes are useful for software components as
  well, especially those with complex user
  interfaces.

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Spiral Model
Software Process Models Chapter 12

• The key characteristics of this model are regular
  assessments of management risks and actions to
  counteract these risks.
• Each cycle of spiral have the following steps
• Specifying objectives
• List alternatives and their constraints
• Assessing each of the alternatives against each
  objective
• The spiral model incorporates other process
  models.

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Twin Life Cycle
Software Process Models Chapter 12

• Different organizational groups are involved in
  systematic reuse
• Domain groups
• Component groups
• Application groups
• Software process models and software reuse
  interact in two ways
• Design with reuse
• Design for reuse
• Provides only a rough overview, but it clearly
  demonstrates activities of groups.

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Domain Analyses
Domain Engineering Chapter 13

• Common objects and operations are likely to occur
  in multiple applications within a domain.
• Domain analyses stresses the reusability of
  analyses and design, not code.
• Domain-specific reuse is usually accomplished by
  separating domain engineering and application
  engineering.

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Domain Analyses
Domain Engineering Chapter 13

• Information Sources
• Existing applications
• Domain experts
• Products
• Domain definition
• Domain model
• Domain requirements model
• Architecture model
• Domain taxonomy
• Domain language
• Domain standards
• Reusable components

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Domain Analyses
Domain Engineering Chapter 13

• In the context of domain analysis we can
  distinguish the following categories
• General purpose
• Domain-specific components
• Product-specific components
• Benefits
• Reuse of domain knowledge
• Reuse of components in a certain context
• Domain-specific model for classification
• Framework for tooling and systems synthesis from
  reusable components
• Large-grain reuse across products
• Identification of reusable software components

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Domain Analysis Activities
Domain Engineering Chapter 13

• Activities in domain analysis have been described
  by various authors.
• Arango has compared several domain analysis
  methods and extracted a common process with the
  following activities
• Domain Definition and Preparation
• Data Collection
• Data Analysis and Classification
• Evaluation

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Domain Definition and Preparation
Domain Engineering Chapter 13

• It is important that a domain be clearly defined
  and its boundaries be established
• After the definition of the domain, relevant data
  has to be identified and collected for the
  acquisition of domain knowledge

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Data Collection
Domain Engineering Chapter 13

• Different approaches for data collection can be
  used, e.g., reviews of literature, interviews of
  experts, analysis of applications.
• In determining reusable components various levels
  can be chosen for analysis
• Different sources of information provide
  different types of information

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Data Analysis and Classification
Domain Engineering Chapter 13

• It is crucial to analyze similarities, variations
  and combinations of data.
• The activities in this step are not entirely
  different from activities in developing a single
  software system.
• Domain information is prepared by abstracting and
  generalizing functions, objects and their
  relationships.

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Evaluation
Domain Engineering Chapter 13

• Besides using and refining models, it helpful to
  evaluate the domain
• Real application developments are the best
  evaluation and test of a domain

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Domain Analysis Methods
Domain Engineering Chapter 13

• Domain analysis methods provide some sort of
  systematic proceeding to do domain analyses
• Argo has presented, compared and evaluated eight
  domain analysis methods
• They are essentially similar, with the main
  differences in
• Emphasis on certain data acquisition means over
  others
• Approach to modeling, e.g., functional vs.
  object-oriented techniques
• Overlapping subsets of notations
• Different groupings of activities with different
  names
• Same names with slightly different meanings

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Foda Feature-Oriented Domain Analysis
Domain Engineering Chapter 13

• It was developed at the Software Engineering
  Institute
• Foda contains the basic phases
• Context Analysis
• Domain Modeling
• Architecture Modeling

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Context Analysis
Domain Engineering Chapter 13

• Define the scope of the domain and its
  relationships to other domain
• Context model
• Structure diagrams
• Data flow diagrams

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Domain Modeling
Domain Engineering Chapter 13

• Analyze commonalties and differences of problems
  being addressed by applications in the domain
• Feature analysis
• Entity relationship modeling
• Functional analysis

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Architecture Modeling
Domain Engineering Chapter 13

• Provide a software solution to problems defined
  during domain modeling.
• The Foda architecture model is a high-level
  design of applications in the domain.

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Domain Implementation
Domain Engineering Chapter 13

• Domain implementation means the use of the
  information collected in domain analysis to
  create reusable components and new systems.