On the horizon

1
On the horizon

• Chapter twenty-five of
• Szyperski, Clemens et al. Component Software -
  Beyond Object-Oriented Programming. Second
  Edition

2
Contents

• Advanced object composition
• Delegation
• Split Objects
• Environmental acquisition
• Dynamic inheritance
• New forms of object and component abstraction
• Subject-oriented programming
• Aspect-oriented programming
• XML Components

3
Advanced object composition

• Class composition is too static for many
  components applications
• Object composition is usually based on message
  forwarding
• The Loss of identity of the whole causes some
  problems

4
Delegation

• Dependencies between base class and subclass
• Delegation-based object composition problem
• Performance aspects

5
Split Objects

• A web of objects with a common identity
  established by means of delegation
• Individually a fragment of a split object does
  not have object status
• Delegations across split objects is excluded in
  this model
• Hierarchical split objects
• Reorganization

6
Environmental acquisition

• Objects are embedded in a containment hierarchy
• Delegation or forwarding requests are sent up the
  containment hierarchy

7
Dynamic inheritance

• The idea is to generalize the concept of a base
  class to that of a base object selected at object
  construction time
• Rely on delegation between an object and its base
  object

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New forms of object and component abstraction

• Fundamental property of objects
• Traditional inheritance
• Supertype

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Subject-oriented programming

• A subject can associate state and behavior with
  an object identifier as required by that subject
• Association of property
• Separation of concerns along hyperplanes

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Aspect-oriented programming

• AOP is about explicitly slicing programs
  according to the various aspects they address
• AOP weavers
• Post-deployment weaving

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XML Components

• XML world is mostly declarative in nature
• Still be necessary to establish an appropriate
  component concept
• XML web services

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Gamut of markets

• Chapter twenty-five of
• Szyperski, Clemens et al. Component Software -
  Beyond Object-Oriented Programming. Second
  Edition

13
Contents

• Component platforms and infrastructure
• Tools
• Professional Services

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Component platforms and infrastructure

• The value of component platforms and
  infrastructure can exceed that of used
  components
• Approaches to reduce the cost of component
  construction

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Component design and implementation tools

• Rests on environmental specifications
• Should use RAD methods
• Use the same environment to prototype a component
  and implente the component
• Support for the construction of models and
  supporting futher metadata

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Component testing tools

• Testing of components is the single most
  demanding aspect of component technology
• Systematic aproach to testing are needed
• Advisable strategies

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Component assembly tools

• Assembly needs to be automated
• Differences from hardware assembly

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Component system diagnosis and maintenance

• Related to component testing
• Diagnosis is tricky because systems consist of
  components from many different vendors
• Diagnosis tools and ways of operation
• Requirements of maintenance

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Component system and framework architects

• These tasks are extremely demanding
• Independent architecture firms can concentrate
  the expertise
• Few clients X Open markets

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Component assembly consultants

• Component assembly is supposedly simple
• Component specializing in assembly of components
  can find a broad market
• COTS (commercial off the shelf)
• Act knowing well the potential and limitations of
  products and helping gauge the risks and benefits

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Component configuration management

• Outsourcing
• Monitoring of component markets
• Development of gradual migration plans and the
  integration
• Migration from monolithic solutions to
  component-based ones

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Component warehouses, marketing, and consulting

• Traditional aspects
• All activities are likely to be fully electronic
• Legal and practical protection offered by
  physical package becomes unnecessary

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Component operators, web services, application
service providers

• Component paired with a service provider forms a
  marketplace service
• Business model will be concentrated in
  provisioning service combined with availability
  and help desk services

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Any question?