Component Generalization and Instantiation

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Component Generalization and Instantiation
Master Thesis Defense

• Pengzhou Yin

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Outline

• Software Reuse
• Formal Specifications
• Reuse through Formal Specifications
• Specification Generalization
• Specification Instantiation
• Conclusions
• Future works

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1. Software Reuse

• Solve software crisis
• Over budget
• Miss deadline
• Poor quality
• Two reuse problems
• Development for reuse - how to build reusable
  components?
• Development with reuse - how to use reusable
  components?

1. Software Reuse
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2. Formal Specifications

• Specification language proof theory
• Higher quality of software
• Increase understandability of software
• Only way to verify the correctness of software
• Early prototyping with executable specifications

2. Formal Specifications
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Algebraic Specifications

• Describe algebraic abstract data types
• ACT ONE
• Part of ISO formal techniques
• Constructing mechanisms
• Sound theories
• Supporting tools

2. Formal Specifications
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3. Reuse through Algebraic Specifications

• Development for reuse
• Specification generalization
• Parameterization of ACT ONE
• Development with reuse
• Specification instantiation
• Actualization of ACT ONE

3. Reuse through Formal Specifications
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4. Specification Generalization

• Creating generic components from specific ones
• Existence of a morphism between generic component
  and specific one
• Three Types of Generalizations
• Syntactic Generalization
• Semantic Generalization
• Formal Parameter Generalization

4. Specification Generalization
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Syntactic Generalization
4. Specification Generalization
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Semantic Generalization
4. Specification Generalization
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Formal Parameter Generalization
4. Specification Generalization
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Problem with Generalization

• How to control the level of abstraction?

4. Specification Generalization
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Solution

• Categorized constructors
• Linear order natural
• Container set, queue, list, stack
• Converter record
• Describe constraints of formal parameters

4. Specification Generalization
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Example of Generalization
STACK of NATURAL
Semantic generalization of Linear Order
Semantic generalization of Container
Syntactic generalization
Semantic generalization of Converter
STACK of ELEMENT
GSTACK1 of ITEM
GSTACK2 of CONTAINER
GSTACK3 of RECORDER
Generalize one specific component to several
generic components
4. Specification Generalization
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5. Specification Instantiation

• Replacing formal parameter by several actual data
  types
• Respecting constraints proof obligations
• Types of Instantiation
• Basic Instantiation specific actual data types
• General Instantiation generic actual data types
• Partial Instantiation only some, not all

5. Specification Instantiation
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Benefits of our Instantiation Operations

• Easy Selection of candidate components
• Easy Matching of operations
• Easy Checking and no proof obligations
• Easy Organization for component library
• Easy Development for reusable components

5. Specification Instantiation
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Example of Instantiation
5. Specification Instantiation
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6. Conclusions

• Three main contributions
• Define in detail several algorithms for
  generalization and instantiation
• Propose to use categorized constructors
• Control the abstraction level
• Govern the instantiation
• Applied to any algebraic specification language
  PVS, CafeOBJ

6. Conclusions
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7. Future works

• Describing algorithms formally
• Designing supporting tools
• Validating generic components

7. Future works
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Questions?