Framework Design by Systematic Generalization

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Framework Design by Systematic Generalization

• Jian Tang
• CSCE 896
• Software Framework and Architecture

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Overview

• Introduction
• Framework Design Activities
• Summary

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Introduction

• Framework Domain
• Hot spot VS. Frozen spot
• Framework design requires a great deal of
  experience and experimentation
• Flexibility and Variability
• 3 heuristics
• start with a fixed application
• work on different variable aspects at one time
• capture and specify the degree of variability and
  flexibility

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Framework Design Activities

• Create Class Model of Fixed Application
• Hot-Spot high-Level Analysis
• Detail Analysis and Specification of Hot-spots
• High-Level design of Hot-Spot Subsystem
• Transform Class Model by Generalization with
  Hot-Spot Subsystem

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Step1 Create Class Model of Fixed Application

• Class Model
• fixed entities
• fixed relationship
• Example
• Editor
• Class diagram in next page

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Step1 Create Class Model of Fixed Application
(Contd)

• Class Diagram of Editor

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Hot Spots

• Characteristics
• Name
• Description
• Responsibility
• Concrete examples
• Variability
• Parameterization
• Granularity
• Multiplicity
• Binding time

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Step 2 3 Hot Spot Analysis

• All variables from the framework domain
• Hot Spot high-level analysis
• collects all hot spots
• Hot spot detail analysis
• create hot spot specification for each hot spot

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Step 2 Hot-Spot High-level Analysis

• Identify and collect all hot spots
• overview of all variability and flexibility
• Editor
• Other Elements besides texts (hs1)
• other composition facilities (hs2)
• different formatting algorithms (hs3)
• portability(hs4)
• variable application window embellishment (hs5)
• look-and-feel standards(hs6)

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Step 3 Hot-Spot Detail Analysis and Specification

• Do separately for each hot spot
• Describe its characteristics
• Partition to elementary HS
• Examples in next page

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Hot-Spot Detail Analysis and Specification (HS1)

• HS1 Variability of basic document elements
• Description other elements besides characters
• Responsibility print, width, height
• Concrete examples graphics, raster pic,
  character
• Variability same interface, different
  implementation
• Parameterization no
• Granularity elementary
• Multiplicity one
• Binding time runtime

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Hot-Spot Detail Analysis and Specification (HS2)

• HS2 Variable aggregation of document elements
• Description more facilities to compose a
  document
• Responsibility basic plus aggregation-related
  responsibility
• Concrete examples row, column
• Variability variable hierarchy of aggregation
• Parameterization no
• Granularity elementary
• Multiplicity n
• Binding time runtime, multiple times

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Hot-Spot Detail Analysis and Specification (HS3)

• HS3 Variability of formatting algorithms
• Description different algorithms
• Responsibility format a document on a service
  request
• Concrete examplesdifferent algorithms
• Variability different algorithms can be used
• Parameterization no
• Granularity elementary
• Multiplicity 1
• Binding time runtime, multiple times

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Hot-Spot Detail Analysis and Specification (HS4)

• HS4Variability of window system
• Description portable in different window systems
• Responsibility drawing operations, iconify,
  resize
• Concrete examples Mac, PM, Windows
• Variability can be used in different window
  system
• Parameterization no
• Granularity elementary
• Multiplicity 1
• Binding time creation time

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Hot-Spot Detail Analysis and Specification (HS5
HS6)

• HS5Variability of user interface embellishments
• Description different window embellishments
• Variability attach different decorations to
  object
• Multiplicity n
• Binding time creation time
• HS6Variability of look-and-feel standards
• Description different look-and-feel standards
• Variability create object from different classes
• Multiplicity 1
• Binding time creation time

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Step 4 High-level Design of Hot-Spot Subsystem

• Hot Spot Subsystem
• base class (typically, abstract)
• common R for all HS alternatives
• concrete derived class
• one of the instance
• possibly, additional classes and relationship
• Hot spot Subsystem design
• derives the high-level design of a hot-spot
  subsystem from the hot-spot specification

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Hot Spot Subsystem

• How to introduce variability and flexibility
• Inheritance
• Inheritance-based hot spot subsystem
• aggregation
• Composition-based hot spot subsystem

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Inheritance-based hot spot sub-system and
composition-based sub-system

• Inheritance-based Vs. Composition-based

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Hot Spot Subsystem

• Three categories
• Nonrecursive
• service provided from one subclass object.
• Pattern Ex. Strategy
• 11 (chain-structured) recursive
• service provided by n chained subclass objects
• Pattern Ex. Decorator
• 1n (tree-structured) recursive
• service provided by a tree of n subclass objects
• Pattern Ex. Composite

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Hot Spot Subsystem (contd)

• Diagrams for three categories

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Hot Spot Subsystem (contd)

• Diagrams for three categories (contd)

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Hot Spot Subsystem (contd)

• Design patterns
• describe typical, common and frequently observed
  relationships among classes.
• Characteristics
• provide a different kind of variability and
  flexibility
• center around a base class and subclass
• some contains additional classes
• Get a clue?
• Structuring a hot-spot system following a design
  pattern

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Hot Spot Subsystem High-level Design

• Derives the high-level design of a hot-spot
  subsystem from the hot-spot specification
• Hot-spot specification
• description of variable aspects
• multiplicity
• kind of variability
• select appropriate design pattern
• examples in next page

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Hot Spot Subsystem High-level Design (contd)

• Examples of hot spot subsystem HL design
• HS1
• Multiplicity 1 gt Nonrecursive DP
• Variability common interface with different
  implementationsgtInterface Inheritance Pattern
• HS2
• Multiplicity n gt 1n recursive DP
• Variability flexible hierarchical aggregation gt
  Composite Pattern

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Step 5 Generalization Transformation

• Transforms the framework class structure and
  generalizes it with regard to one aspect
• Transform frozen spot to hot spot subsystem
• replace fixed, specialized class with hot spot
  subsystem.

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Expanding VS. Extending

• Expanding transformation
• the base class of the HS subsystem is introduced
  as a new class
• Extending transformation
• the responsibility of an existing class is
  extended by the responsibility of the base class

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Expanding Transformation

• Example (HS1)

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Extending Transformation

• Example (HS2)

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Transformations Generalizing the Editor

• Introducing Hot spot 4

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Transformations Generalizing the Editor

• Introducing hot spot 1

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Transformations Generalizing the Editor

• Introducing hot spot 2

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Transformations Generalizing the Editor

• Introducing hot spot 5

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Transformations Generalizing the Editor

• Introducing hot spot 6

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Transformations Generalizing the Editor

• Introducing hot spot 4

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Summary

• 5 activities
• Review 3 important phases
• Hot spot specification
• Hot spot subsystem high-level design
• Transformations