Facilitating Reuse of Software Components using Repository Technology

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Facilitating Reuse of Software Components using
Repository Technology

• J. Lee, J. Kim, and G.S. Shin
• Electronics Telecommunications Research
  Institute
• Tenth Asia-Pacific SE Conference (APS03EC)
• Presentation by Matthew Choi

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Summary

• Component-Based Development provides many
  benefits through its component reuse
• Savings in development effort and time
• Increase in modifiability and maintainability
• Component repository is required to facilitate
  storing and maintaining reusable software
  components efficiently
• Functional requirements need to be considered for
  an effective component reuse
• Description and implementation of the component
  repository for an EJB component (CRECOR)

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Background

• What is a software component?
• Unit of software that has business logic, and
  interfaces to interact with others
• Highly cohesive units provide low coupling when
  integrated
• Component Based Development
• Approach in which software systems are developed
  by assembling preexisting components under
  well-defined architecture or framework
• Notable benefits include reusability, easy
  maintainability, and faster time-to-market

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Implementation of Services in CBD

• Basic steps involved in implementing a range of
  services in component-based software
• Identify a set of compatible components from
  existing components
• Components that do not operate correctly together
  should be modified according to dependencies b/w
  other components
• Modified components are tested to check for
  functionality and correctness of the changes

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Challenges with CBD

• Difficulty in identifying and locating reusable
  components
• What components to reuse, and where to find them
• Poor quality of component documentation and
  specification
• How should the components be used?
• Are there dependencies with other components?
• Difficulty in governance and management of
  components inventory
• Especially as the number of components grow and
  the complexity of components become greater

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Solution Component Repository

• Allows convenient access to reusable components
• Provides reuse functionalities
• Selection
• Analysis
• Adaptation
• Test
• Deployment
• Components should be collectively stored and
  maintained for future reuse
• To be implemented and integrated with COBALT
  (Component-based application development tool)

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Requirements of Reuse Software Component
Repository

• For reuse functionality, requirements include
• Storing and browsing of components
• Ease of access and availability of components
• Detailed documentation with specifications
• Well-defined interfaces and connectors
• Relationships and dependencies with other
  components
• Additional supports needed in reuse process
• Organizational requirements
• Provide categorizations of components
• Components to be newly generated
• Components to be modified

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Reuse Process with CBD

• 2 main activities involving component reuse
• For component reuse
• Composed of purchase, development, and store
  tasks
• With component reuse
• Composed of search, selection, analysis,
  adaptation, assemble, deployment, and test tasks
• Use specification to determine reusable scope of
  the component
• Can be further divided into
• With component reuse
• With component reuse to be adapted

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Reuse Process (Illustration)
LEFT With-component reuse CENTER With-compone
nt reuse to be adapted RIGHT For-component reuse

• Figure 1 Component-based development process

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Example Component Repository for Facilitating EJB
Component Reuse

• EJB component (physically packaged JAR file)
• Class files (interfaces and beans)
• Deployment descriptors
• Information such as JNDI and class names, methods
  signatures of interfaces, referencing resources,
  etc.
• Manifest file
• Component Repository for facilitating EJB
  Component Reuse (CRECOR)
• Provides functions - component browse, selection,
  analysis, adaptation, deployment, and test
• Its GUI provides easy-to-use interface

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COBALT (CB app. development tool)

• Available functions
• A For-component reuse
• ADD
• B With-component reuse
• VIEW
• TEST
• ADAPT
• DEPLOY

• Figure 2 The stitched box represents CRECOR

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Implementation of CRECOR

• Functions in CRECOR
• For-component reuse
• ADD
• With-component reuse
• VIEW, TEST, ADAPT, and DEPLOY
• The individual function is integrated in the tree
  style component-browsing repository, and is
  operated with its own user interface
• The with-component reuse functions are
  implemented and produced in component viewer,
  analyzer, adapter, deplorer, and tester

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CRECOR - Component Analyzer

• Analyzes component information, and shows
  component structure and its interface methods
• Used to determine the reusable part and scope of
  the selected components
• Each tab represents a bean
• Displays interface names, JNDI, and method
  signatures

• Figure 3 Analyze component information

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CRECOR - Component Adapter

• Supports component modification for mismatched
  interfaces
• Unmatched interface method is adapted in
  following viewpoints return type, parameter
  type, parameter order, and method name
• Also allow addition of new attributes or
  interfaces

• Figure 3 Add new attributed activated view

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CRECOR - Component Deplorer

• Supports component packaging and deployment
• Input values are used for component packaging,
  deployment descriptor writing, and deploying in
  various J2EE-based application servers

• Figure 4 J2EE-based component deplorer

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CRECOR - Component Tester

• Supports testing interface methods for determined
  reusable parts of a specific component without
  manual coding
• Available for automatic client program generating
  and interface method self-testing with parameter
  values provided at runtime

• Figure 5 Automatically generates web-based
  client program

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Architecture Diagram Editor

• Provides visualization of component architecture
• Use drag-and-drop to show interconnection of
  reusable components involved

• Figure 6 Visual representation of the CB
  architecture

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Conclusion

• CRECOR is designed and implemented to support
  process for component reuse
• Provides reuse facilities that are almost
  necessary for CBD
• Provides useful functionalities to facilitate a
  successful CBD such as specification viewing,
  component adaptation for compatibility, etc.
• Overall savings in development time, effort, and
  costs

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Critique

• Strengths
• General idea and concept of utilizing repository
  technology with CBD was very interesting
• The description of the tools used for the
  discussion (COBALT CRECOR) were well organized
  and illustrated
• Weaknesses
• Limitations of these tools were not discussed
• Found grammatical errors, and some sentences were
  not easily comprehensible (attributed to ESL)

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Discussion Topics

• The tools described in the paper seems to only
  focus on storing and managing the actual
  components. How else can these types of tools be
  leveraged to improve CBD using this repository
  concept? For example, what other types of
  artifacts should be in the repository? Or what
  other features of the repository might be useful?
• These tools do not seem to address potential
  security and administrative restriction issues.
  Are these necessary? If so, how should it be
  administered?
• Have any of you had exposure to CBD component
  repository? What are some of the recent
  repository systems available today?