a framework, methodology and tool for reusable software components*

REUSE--1

A Framework, Methodology and Tool A Framework, Methodology and Tool for Reusable Software Components*for Reusable Software Components*

Prof. Steven A. Demurjian, Sr.,Jeffrey R. Ellis, Rodrigo Caballero,

Felix Eickhoff, Shaikit Das, and Xiaopei Wang Computer Science & Engineering Department

The University of ConnecticutProf. Donald M. Needham

Computer Science DepartmentU.S. Naval Academy

[email protected]@[email protected]

http://www.engr.uconn.edu/~steve(860) 486 - 4818

*Work supported in part by a grant from Electric Boat, Inc., Groton, CT.

REUSE--2

MotivationMotivation Reuse Afterthought in OO Design/DevelopmentReuse Afterthought in OO Design/Development Majority of Reuse Focuses on “Small” Majority of Reuse Focuses on “Small”

Components with Minimal SavingsComponents with Minimal Savings String Functions, Utility Routines, GUI, etc. Easy to Understand - Easy to Reuse

““Beans” Have Improved Reuse - Still LaggingBeans” Have Improved Reuse - Still Lagging Three Classes of Software Three Classes of Software

Domain-Independent (20%) : Libraries, Utilities, etc. Most Likely to Be Reused

Domain-Specific (65%) : Dedicated SoftwareReused in Other Programs of Same Domain

Application-Specific (15%): UniquenessUnlikely to Be Reused

REUSE--3

MotivationMotivation Popular OO Design Methodologies Omit and Popular OO Design Methodologies Omit and

Ignore Reuse GuidelinesIgnore Reuse Guidelines Unified Modeling Language - UML Design Patterns - Reuse Pattern/Not Software

Current Research Concentrates on Current Research Concentrates on ConsumerConsumer (Reuser) and Not (Reuser) and Not ProducerProducer (Creator) (Creator) Measure Savings from Reuse Calculate Return on Investment

Two-Fold GoalTwo-Fold Goal Elevate Reuse to Equal Partner Starting with

Design Focus on Domain-and-Organization Specific

Reuse

REUSE--4

MotivationMotivation

Three Classes of Softwarein a Typical Software Application

Domain-Independent20% Domain-Specific

65%

Application-Specific15%

REUSE--5

MotivationMotivationWhy Software Reuse?Why Software Reuse?

Increase Software Productivity Increase Software Productivity Shorten Software Development Time Shorten Software Development Time Improve Software System Interoperability Improve Software System Interoperability Develop Software With Fewer People Develop Software With Fewer People Move Personnel More Easily From Project to Move Personnel More Easily From Project to

Project Project Reduce Software Development and Maintenance Reduce Software Development and Maintenance

Costs Costs Produce More Standardized Software Produce More Standardized Software Produce Better Quality Software Produce Better Quality Software Provide a Powerful Competitive AdvantageProvide a Powerful Competitive Advantage

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ObjectivesObjectives Reuse as Equal Partner Starting with DesignReuse as Equal Partner Starting with Design

Iterative Reusability Evaluations at Early and All Stages of Design and Development

Production of Large Reusable Components Capabilities of Evaluation TechniquesCapabilities of Evaluation Techniques

Identify the Reusable Portions of Design Estimate/Measure Reusability Automatically Provide Guidelines on Improving Reusability Usable for

Newly Created Designs Evaluation of Legacy Code for Reuse Potential

Integrated in a Design/Development Environment

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Overview of PresentationOverview of Presentation Cultural and Social Reuse IssuesCultural and Social Reuse Issues Component-Based Design - History & PerspectiveComponent-Based Design - History & Perspective Reuse Framework and MethodologyReuse Framework and Methodology

Subjective Identification of Components General vs. Specific Classes Related Hierarchies to Quantify Components

Objective Measure of Dependencies Classifying Dependencies Measuring Reuse Potential

Reuse Guidelines Methodological Basis for Increasing Reuse Iterative Improvement in Reusability

Prototyping: DRE Tool Family/ExamplesPrototyping: DRE Tool Family/Examples Conclusions and Future ResearchConclusions and Future Research

REUSE--8

Cultural and Social Reuse IssuesCultural and Social Reuse IssuesManagement SupportManagement Support

Motorola Study:Motorola Study: A New Reuse Program there must A New Reuse Program there must have Strong/Unequivocal Management Supporthave Strong/Unequivocal Management Support

Raytheon Report:Raytheon Report: Support from Upper Support from Upper Management Most Important for Successful ReuseManagement Most Important for Successful Reuse

Why? IncreasedWhy? Increased Cost Associated with Constructing Reusable

Components Communication, Coordination Education, Training

Motorola and Raytheon Facilitate by IncentivesMotorola and Raytheon Facilitate by Incentives Both Producer and Consumer Benefits Awards Provided for Demonstrated Efforts

REUSE--9

Cultural and Social Reuse IssuesCultural and Social Reuse IssuesHigh Initial CostHigh Initial Cost

Reports have IndicatedReports have Indicated High Start Up Costs Slow Return on Investment (> 3 years)

Best Success inBest Success in Starting with Small Projects Distributing Components for Reuse Opportunistic Reuse

Reuse Must be Supported byReuse Must be Supported by Libraries to Collect, Classify, and Disseminate

Components Ease of use for Producer and Consumer

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What are Components?What are Components? ADTs as Unit of Abstraction/ConceptualizationADTs as Unit of Abstraction/Conceptualization Classes are OO Equivalent of ADTsClasses are OO Equivalent of ADTs However, in Past 10 YearsHowever, in Past 10 Years

Computing Power has Exploded Application Complexity has Increased Classes are Part of Inheritance Hierarchy Inheritance Hierarchy Part of Application Class

Library In Past 2-3 Years We’ve SeenIn Past 2-3 Years We’ve Seen

Emergence of Java Emergence of Java Beans Component-Based Development Tools

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What are Components?What are Components? How are Applications Conceptualized?How are Applications Conceptualized?

Inheritance Hierarchies Partition Domain Packages as Collections or Related Classes Collections of Classes, Packages, Inheritance

Hierarchies form Application Class Library How are Class Libraries Utilized?How are Class Libraries Utilized?

Use Individual Classes Use Package or Subset of Package Use Major Portions of Inheritance Hierarchies Tools Use at Most a “Few” Select Packages

and/or Hierarchies Tools that Span Application Classes Represent

Poorly Designed Software

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Defining Component ConceptsDefining Component Concepts A A ComponentComponent is Composed of One or More is Composed of One or More

Classes (or Other Components) and is Intended to Classes (or Other Components) and is Intended to Support a “Constructed” Unit of Functionality Support a “Constructed” Unit of Functionality

ClassesClasses Can be Utilized in Can be Utilized in Multiple ComponentsMultiple Components A Class Utilized in Multiple Components A Class Utilized in Multiple Components

Maintains the “Maintains the “SameSame” ” SemanticsSemantics in All of its in All of its ContextsContexts

Our Interest Involves:Our Interest Involves: Reusable Classes Reusable Components A Reusable Component Consists of Classes

and/or Other Components that are Expected to be Reused Together in Future Applications

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Cultural and Social Reuse IssuesCultural and Social Reuse IssuesReuse and Software Design/DevelopmentReuse and Software Design/Development Lesson LearnedLesson Learned

Reuse Often Avoided by SW Engineers due to Fear of Configuration Management Problems

How is Fear Minimized?How is Fear Minimized? Reuse as Integral Part of Development Process Reuse Early and Often Tools that Facilitate Producer Logging

Component and Consumer Finding Component SummarySummary

We’ll Concentrate on Technical Reuse Issues Superior Techniques Will Remain Unpopular

and Unused without Associated Support

REUSE--14

Components vs. ObjectsComponents vs. Objects ComponentsComponents

Business Oriented Coarse Grained Standards Based Multiple Interfaces Provide Services Fully Encapsulated Understood by

Everyone

ObjectsObjects Technology-Oriented Fine Grained Language Based Single Interface Provide Operations Use Inheritance Understood by

Developers

REUSE--15

Reusable Components Reusable Components Types & BenefitsTypes & Benefits

Application Template Application Template Data Model Data Model Data Structure Data Structure System Architecture System Architecture Process Model Process Model Process Definition Process Definition Prototype Prototype Plan Skeleton Plan Skeleton User Interface User Interface

Skeleton/GUISkeleton/GUI Process SkeletonProcess Skeleton Utility ComponentsUtility Components

Organizational Organizational PerspectivePerspective Shorten Development

Time Reduce Costs Increase

Competitiveness Personnel PerspectivePersonnel Perspective

Increase Productivity Customer Perspective Customer Perspective

Achieve Greater User Satisfaction Through the Production of More Flexible Products

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Component-Based Development ProcessComponent-Based Development Process

TOP-DOWN:To determine what is needed to satisfy this need.

BOTTOM-UP:To determine what is available to satisfy this need.

OTHERS:Consider the similarity among concurrent projects.

FUTURE:Consider the possibility of reusing in future projects.

REUSE--17

CBD: Component-Based DevelopmentCBD: Component-Based Development

REUSE--18

Supplier /Consumer ModelSupplier /Consumer Model

SUPPLY Build New Wrap Existing Buy

CONSUME Assemble Applications

MANAGE Publish Subscribe Catalog Browse

REUSE--19

SpecificationSpecification

ImplementationImplementation

ExecutableExecutable

InterfacesInterfaces

ComponentComponent

REUSE--20

Components as Assets can GrowComponents as Assets can Grow

Complexity of ComponentComplexity of Component

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What are Component Dependencies?What are Component Dependencies?

Dependency Type of ComponentsDependency Type of Components VersionsVersions AggregationsAggregations FunctionalFunctional InheritanceInheritance AssociationAssociation

What is Impact of Each Dependency on the What is Impact of Each Dependency on the Reusability of a Component?Reusability of a Component?

REUSE--22

Component-Based Tools/Web Sites of NoteComponent-Based Tools/Web Sites of Note

Software Software Composition Composition WorkbenchWorkbench

JavaBeansJavaBeans Visual CaféVisual Café Visual J++Visual J++ Sun’s ForteSun’s Forte Enabler, SoftlabEnabler, Softlab Microsoft Microsoft

RepositoryRepository UREP, UnisysUREP, Unisys Select Software Select Software

Tools, SelectTools, Select

Reusable Software Research Group, Reusable Software Research Group, West Virginia University West Virginia University http://www.csee.wvu.edu/~resolve/scw/rsrg

-brochure-nov-98.html Reusable Software Research Group, Reusable Software Research Group,

Ohio State UniversityOhio State University http://www.cis.ohio-state.edu/rsrg

/index.html Select Software ToolsSelect Software Tools

http://www.selectst.com/ Software Reuse Executive Primer, Software Reuse Executive Primer,

DODDOD http://dii-sw.ncr.disa.mil/ReuseIC/pol-

hist/primer/ Model-Driven Software Reuse, Model-Driven Software Reuse,

Extended Intelligence Inc.Extended Intelligence Inc.

http://www.csee.wvu.edu/~resolve/scw/rsrg-brochure-nov-98.html













http://www.cis.ohio-state.edu/rsrg/index.html









http://www.selectst.com/Component/Default.ASP



http://dii-sw.ncr.disa.mil/ReuseIC/pol-hist/primer/

http://dii-sw.ncr.disa.mil/ReuseIC/pol-hist/primer/

REUSE--23

RepositoryRepositoryBrowserBrowser

HierarchyHierarchy

Component RepositoryComponent Repository

REUSE--24

Multiple Repository SupportMultiple Repository Support

Multiple SupportMultiple Support

REUSE--25

CBD life cycleCBD life cycle

BusinessBusinessDirectionDirection

General BusinessGeneral BusinessRequirementsRequirements

User, BusinessUser, Businessand Data servicesand Data services

Business andBusiness andData servicesData services

ComponentComponentRequirementsRequirements

UserUserServicesServicesHarvestHarvest

REUSE--26

1996: $652 million1996: $652 million 2001: $12 billion2001: $12 billion

IDC forecast CBD marketIDC forecast CBD market

REUSE--27

Web-Site ReferencesWeb-Site References Reusable Software Research Group, West Reusable Software Research Group, West

Virginia UniversityVirginia University http://www.csee.wvu.edu/~resolve/scw/rsrg-brochure-

nov-98.html Reusable Software Research Group, Ohio Reusable Software Research Group, Ohio

State UniversityState University http://www.cis.ohio-state.edu/rsrg/index.html

Select Software ToolsSelect Software Tools http://www.selectst.com/

Software Reuse Executive Primer, DODSoftware Reuse Executive Primer, DOD http://dii-sw.ncr.disa.mil/ReuseIC/pol-hist/primer/

Model-Driven Software Reuse, Extended Model-Driven Software Reuse, Extended Intelligence Inc.Intelligence Inc.

REUSE--28

A Framework, Methodology, and Tool for A Framework, Methodology, and Tool for Reusable Software ComponentsReusable Software Components

Reuse as Equal Partner Starting with DesignReuse as Equal Partner Starting with Design Iterative Reusability Evaluations at Early and All

Stages of Design and Development Production of Large Reusable Components

Capabilities of Evaluation TechniquesCapabilities of Evaluation Techniques Identify the Reusable Portions of Design Estimate/Measure Reusability Automatically Provide Guidelines on Improving Reusability Usable for


Independent Tool/Integrated in Together CC See: http://www.engr.uconn.edu/~steve/DRE/dre.html

REUSE--29

A Framework, Methodology, and Tool for A Framework, Methodology, and Tool for Reusable Software ComponentsReusable Software Components

1. Define Components, Their 1. Define Components, Their Interactions, and Analyze Interactions, and Analyze Their ReusabilityTheir Reusability

2. Store an Iteration of Design2. Store an Iteration of Design3. Implement an Iteration3. Implement an Iteration4. Store and Document 4. Store and Document

Iteration of ImplemenIteration of Implemen..5. Reevaluate an Existing 5. Reevaluate an Existing

Design forDesign for Correcting Errors New Reuse Potential

6. Reuse Existing Design with 6. Reuse Existing Design with a New Implementationa New Implementation

Store &DocumentDesigns

ReusabilityEvaluation

Implementthe System

Re(Design)a System

Store &DocumentImplemens.

11

55

4466 33

22

REUSE--30

Subjective IdentificationSubjective Identification ofof ComponentComponentss Reuse Historically Occurs at Class LevelReuse Historically Occurs at Class Level Class as “Atomic” Component only Scratches Surface Class as “Atomic” Component only Scratches Surface

in Reuse Potential for OOin Reuse Potential for OO But, Classes InteractBut, Classes Interact

If Reuse One, Often Need Others Thus, Reuse Set of Classes

Expand Reuse from Class to Component LevelExpand Reuse from Class to Component Level Establish Framework for Promoting Design ReuseEstablish Framework for Promoting Design Reuse

Characterize General vs. Specific Classes Quantify Related Components Illustrate via HTSS and Financial Frame

Applications Goal: Increase Reuse Potential by Understanding Goal: Increase Reuse Potential by Understanding

Classes, Components, and their Role within Appl.Classes, Components, and their Role within Appl.

REUSE--31

General/Specific ClassGeneral/Specific Class CharacterizationCharacterization Subjective Characterization by Software DesignerSubjective Characterization by Software Designer Best Estimate on Potential Utility of ClassBest Estimate on Potential Utility of Class General Class (G)General Class (G)

Those Application Classes that Facilitate Domain-and-Organization Specific Reuse

Specific Class (S)Specific Class (S) Those Application Classes that are Limited to

use in a Single Application PurposesPurposes

Determine Classes with Highest Reuse Potential for Organization’s Future Systems

Dependencies from General to Specific are both Non-Reusable and Hinder Reuse

REUSE--32

General/Specific ClassGeneral/Specific Class CharacterizationCharacterization General Class (G)General Class (G)

Expected to be Reused in Future Applications Abstract Classes/Root Classes/Non-Leaf

Classes in Inheritance Hierarchies Domain Independent/Domain Specific What are Some Examples?

Specific Class (S)Specific Class (S) Only Applicable in Current Applications Unlikely to be Reused in Future Applications Classes that Retrieve from Company Database Application Specific What are Some Examples?

REUSE--33

High-Tech Supermarket System (HTSS)High-Tech Supermarket System (HTSS)

Automate the Functions and ActionsAutomate the Functions and Actions Cashiers and Inventory Updates User Friendly Grocery Item Locator Fast-Track Deli Orderer Inventory Control

User System Interfaces User System Interfaces Cash Register/UPC Scanner GUI for Inventory Control Shopper Interfaces Locator and Orderer Deli Interface for Deli Workers

We’ll Introduce and Utilize Throughout Lecture

REUSE--34

The HTSS Software ArchitectureThe HTSS Software Architecture

ICICICIC

CRCRCRCR

CRCR

CRCR

ILILILIL

ILILSDOSDO

SDOSDO EDOEDO

EDOEDO

OrderOrder

PaymentPayment

ItemItemItemDBItemDBLocalLocalServerServer

Non-LocalClient Int.

InventoryInventoryControlControl

ItemDBItemDBGlobalGlobalServerServer

OrderDBOrderDB

SupplierDBSupplierDB

CreditCardDBCreditCardDB

ATM-BanKDBATM-BanKDB

IL: Item IL: Item LocatorLocator

CR: Cash RegisterCR: Cash RegisterIC: Invent. ControlIC: Invent. Control

DO: Deli Orderer forDO: Deli Orderer for Shopper/EmployeeShopper/Employee

REUSE--35

A General Class in HTSSA General Class in HTSS Why is Why is ItemItem General? General? What is Applicability of What is Applicability of ItemItem??

class Item { private: // Private Data int UPC; char* Name; int InStock, OnShelf, ROLimit; float RetailCost; public: // Public Methods Item(int code, char* str, int st1, int st2, int st3, float cost); void CreateNewItem(); int GetUPC(); char* GetName(); int GetQuantity(); int CheckReorderStatus(); void PrintItem(); void UpdatePrice(float new_value); };

REUSE--36

Another General Class in HTSSAnother General Class in HTSS Collection Classes of General Classes are General Collection Classes of General Classes are General

class ItemDB {private: int Num_Items; int Curr_Item; Item* AllItems[Max_Items];

int FindFirstItem(); int FindNextItem(); int FindItemUPC(int code); int FindItemName(char* name); public: ItemDB(); // Constructor void InsertNewItem(Item* new_one); void DeleteExistingItem(int code); void FindDisplayItemUPC(int code); void FindDisplayItemName(char* name); void PrintAllItems(); };

REUSE--37

Yet Another General Class in HTSSYet Another General Class in HTSS GUI-Based Class for Supporting Inventory GUI-Based Class for Supporting Inventory

Control Actions Can be Domain IndependentControl Actions Can be Domain Independent

class InvControlGUI { private: int Curr_Option; // Current menu option public: InvControl(); // Constructor void PrintMenuSetOption(); void ActivateController(); void EnterNewItem(); void RemoveExistingItem(); void FindItem(); void InvSearchQuantity(); void InvSearchReorder(); void GenerateAnOrder();};

REUSE--38

Specific Classes in HTSSSpecific Classes in HTSS

General Classes are Refined to Represent General Classes are Refined to Represent Particular Items, Yielding Specific ClassesParticular Items, Yielding Specific Classes

...

Item

DairyItemProduceItem DeliItem

DeliOrdererGUI

OrdererGUI

REUSE--39

Levels of General ClassesLevels of General Classes Not All General Classes Created EquallyNot All General Classes Created Equally Level of Generality Based on Role in ApplicationLevel of Generality Based on Role in Application

PurposesPurposes Accommodate Large Systems with Multiple,

Different Reusable Components Reusable Components can Overlap, but Still be

Distinct Reusable Units

S,...,G,G,G 2100G

2G0G 0G

1G

2G S

S1G views as General if i j views as Specific if i < j

iG jG

jGiG

REUSE--40

...

Can you Identify Different Levels Can you Identify Different Levels of General Classes?of General Classes?

Item

DairyItemProduceItem DeliItem

NonPerishItem PerishItem

)(G0

)(G1 )(G1

REUSE--41

...

Can we Identify Different Levels Can we Identify Different Levels of General Classes?of General Classes?

DairyItem DeliItem

Item

ProduceItem


)(G0

)(G1 )(G1

)(G2)(G2

BigYProdItem DoleProdItem BigYDairyItem HoodDairyItem

Where can ItemWhere can Itembe Reused?be Reused? Where can Where can

NonPerishItem NonPerishItem and PerishItemand PerishItembe Reused?be Reused?

Where can ProduceItem and Where can ProduceItem and DairyItem be Reused?DairyItem be Reused?

Are DoleProdItem and HoodDairyItem Specific?Are DoleProdItem and HoodDairyItem Specific?

REUSE--42

Properties of General/Specific ClassesProperties of General/Specific Classes Level of Generality Strictly Ordered in HierarchyLevel of Generality Strictly Ordered in Hierarchy A Descendant of a General Class Must have an A Descendant of a General Class Must have an

Index Greater Than or Equal to Itself or be SpecificIndex Greater Than or Equal to Itself or be Specific A Specific Class Can only have Specific A Specific Class Can only have Specific

DescendantsDescendants

S,...,G,G,G 2100G

2G0G 0G

1G

2G S

S1G views as General if i j views as Specific if i < j

iG jG

jGiG

REUSE--43

Generality and Specificity Generality and Specificity within One Inheritance Hierarchywithin One Inheritance Hierarchy

G

GG

S

G

G

SS

S

SS

Fi g . G e n e r a l ( G ) / S p e c i f i c ( S ) C l a s s e s o f a H i e r a r c h y

REUSE--44

Generality/Specificity/DependenciesGenerality/Specificity/DependenciesAcross Multiple HierarchiesAcross Multiple Hierarchies

G

SG

GS

S

S

SS

G

GG

S

G

G

SS

S

SS

Fi g . Ty p e s o f C o u p l i n g s b e t w e e n C l a s s H i e r a r c h i e s

REUSE--45

General/Specific Paradigm in HTSSGeneral/Specific Paradigm in HTSS

Abstraction from Abstraction from HTSSHTSS to to Domain IndependentDomain Independent Inventory Control ApplicationInventory Control Application

Separation of Supermarket Domain SpecificsSeparation of Supermarket Domain Specifics Leverage Commonalties for Leverage Commonalties for

Focused, Independent Design/Development Future Products

RelevanceRelevance Domain-and-Organization-Specific Reuse Expand to 24 hour Mom & Pop Stores Expand to Other Retail Markets

E.g., Auto parts, Clothing, Toy, etc.

REUSE--46

Reusability in HTSS DomainReusability in HTSS Domain

Where do Changes for Other Domains Occur?Where do Changes for Other Domains Occur?

Specific Applications for Big Y or Shaw’s or Stop/Shop (S)

Root classes for Items, ItemDB, etc., which are Most General.

Inventory Control/Other Components.

Classes Specific to Grocery Store Domain.

)(G0

)(G1

)(G2

REUSE--47




Inventory ControlOther Components.


)(G0

)(G1

)(G2

Inventory Control Tool for Ordering Items from Suppliers

Cost Accounting Tool for Tracking Net and Gross Profit

REUSE--48





Classes Specific to Grocery Store Domain.)(G0

)(G1)(G2

Classes forLargeSupermarket

Classes forSpecialtySupermarket

Classes for24 HourConvenience

REUSE--49

The FinancialFrame ApplicationThe FinancialFrame Application

A Commercial C++ Framework Containing 441 A Commercial C++ Framework Containing 441 Classes, Proprietary of FinancialCompClasses, Proprietary of FinancialComp

Designed for Reuse in Various Financial Apps.Designed for Reuse in Various Financial Apps. Provides Basic Functionalities of Financial SystemProvides Basic Functionalities of Financial System FinancialFrame’s Challenge - Manage ChangesFinancialFrame’s Challenge - Manage Changes

Framework Constantly Evolving New Functions and Modify Existing Functions

Conceptual Relevance:Conceptual Relevance: Provide Realistic Context for Our Approach Domain-and-Organization-Specific Reuse

REUSE--50

The FinancialFrame ApplicationThe FinancialFrame Application

Our Purpose: Work with Existing CodeOur Purpose: Work with Existing Code Establish General and Specific Classes Characterize Related Components Evaluate the Goodness of G/S Characterization

and Identify Potential Problem Areas General Components that are Specific Specific Components that are General

Problematic Relevance:Problematic Relevance: Demonstrate Ability of Approach to Localize

Effect of Changes Describe Ways to Increase FinancialFrame’s

Reuse Potential

REUSE--51

General and Specific Classes in General and Specific Classes in FinancialFrameFinancialFrame

FinancialCompTrader )(G2

FinancialCompAccount )(G2

FinancialCompDesk )(G2

)(G0Main

FinancialCompMain OtherMain

SpecificFCMain (S) SpecificOtherMain (S)

)(G2 )(G2 ...

)(G0YieldModel

DiscountIndexBond )(G1 )(G1 Bill )(G1

)(G0CashFlowAnalyzer

...

REUSE--52

Related Classes and HierarchiesRelated Classes and Hierarchies Class X is Related to Class YClass X is Related to Class Y if they are Related if they are Related

and Concept and are and Concept and are Expected to be ReusedExpected to be Reused TogetherTogether in Future Systems in Future Systems

Class X Related to Class Y is Class X Related to Class Y is Subjectively Subjectively AssignedAssigned by Software Engineer (Producer) by Software Engineer (Producer)

When Class X is Related to Class YWhen Class X is Related to Class Y X and All of X’s Descendants are Related to

Y and All of Y’s Ancestors Thus, to Reuse X or X’s Descendants, you

Must Reuse Y and All of Y’s Ancestors Class X Related to Y if Y at Same or Higher

Level! Related Classes Promote Reuse, Since They are Related Classes Promote Reuse, Since They are

Expected to be Reused TogetherExpected to be Reused Together

REUSE--53

Related Hierarchies/Reusable Related Hierarchies/Reusable ComponentsComponents

Two Sub-Hierarchies are Related if to Reuse One, Two Sub-Hierarchies are Related if to Reuse One, you Must Reuse the Otheryou Must Reuse the Other

Purpose: Purpose: Identify Reusable Dependencies Among Identify Reusable Dependencies Among Related ClassesRelated Classes

Reusable Component: Reusable Component: A Set of Related Classes that A Set of Related Classes that are Expected to be Reused as a Groupare Expected to be Reused as a Group

0G

0G 0G

S0G

0G

S0G

S

A Sub-Hierarchies BA Sub-Hierarchies B

RR

REUSE--54

Related Characterization in Related Characterization in Levels of Components - HTSSLevels of Components - HTSS

Item


)(G0

)(G1 )(G1 Environ )(G1RR

DairyItemProduceItem DeliItem SubZero RTemp

Does Does RR from Environ to PerishItem Make Sense? from Environ to PerishItem Make Sense? Should Should RR be from PerishItem to Environ? be from PerishItem to Environ?

REUSE--55

Related Characterizations in Related Characterizations in Levels of Components - HTSSLevels of Components - HTSS

Where do Changes for Other Domains Occur?Where do Changes for Other Domains Occur?





)(G0

)(G1

)(G2

REUSE--56

Related Characterization in Related Characterization in Levels of Components - FinancialFrameLevels of Components - FinancialFrame

...

)(G0YieldModel


Bond )(G1

R

Bond is Related to IndexBondBond is Related to IndexBond When Bond is Reused, so Must IndexBond and When Bond is Reused, so Must IndexBond and

YieldModel YieldModel Hence, IndexBond and its Ancestor (YieldModel) are Hence, IndexBond and its Ancestor (YieldModel) are

Reused!Reused!

REUSE--57

Related Characterizations in Related Characterizations in Levels of Components - FinancialFrameLevels of Components - FinancialFrame

Classes/Sub-Hierarchies can be Related if and only Classes/Sub-Hierarchies can be Related if and only if Classes (or Sub-Hierarchy Roots) are General if Classes (or Sub-Hierarchy Roots) are General and at the Same or Higher Leveland at the Same or Higher Level

Specific applications at FinancialComp (S)

Root classes of strategies andother most General classes (Main)

Bond or other strategy Components

Classes specific to FinancialComp

)(G0

)(G1

)(G2

REUSE--58

What are Dependencies Among Classes?What are Dependencies Among Classes?

Object Inclusion: Object Inclusion: Class Contains a Instance of Class Contains a Instance of Another ObjectAnother Object

Attribute Definition: Attribute Definition: Class Contains Attribute that Class Contains Attribute that is the Type of Another Objectis the Type of Another Object

Method Invocation: Method Invocation: Class Invokes a Method Class Invokes a Method Defined on Another ObjectDefined on Another Object

GoalsGoals Classify and Understand Dependencies Assess “Good” vs. “Bad” Dependencies Change “Bad” to “Good” by

Changing Class from S to G or G to S Moving Code and/or Method Calls Splitting a Class into Two Classes Merging Two Classes

REUSE--59

Reusing Sub-Hierarchies in Reusing Sub-Hierarchies in Different Components - HTSSDifferent Components - HTSS

Will be reused with Componentsfor another domain,e.g., Toy Store

Will be reused with Componentsfor different Super-market Companies

Item

...DairyItemProduceItem DeliItem


REUSE--60

Reusing Sub-Hierarchies in Reusing Sub-Hierarchies in Different Components - FinancialFrameDifferent Components - FinancialFrame

Dependencies Among General Related ClassesDependencies Among General Related Classes Not a Hindrance to Reuse Represents Valuable Design Knowledge

)(G0Main

FinancialCompMainOtherMain

SpecificFCMain (S)SpecificOtherMain (S)

)(G2)(G2

Will be reused with Componentsutilizing another company’s databases

Will be reused with Componentsutilizing FinancialComp’s database

REUSE--61

Transitivity in Inheritance and Transitivity in Inheritance and Related RelationshipsRelated Relationships

Base CaseBase Case: Related Characterization is : Related Characterization is TransitiveTransitive, , but not but not CommutativeCommutative

A B CR R

Case 1Case 1: A is : A is notnot related to X related to X Dependencies from A to X Dependencies from A to X are are notnot Desirable Desirable

Recall: We Reuse X and AllRecall: We Reuse X and All of Its Ancestors, But Not of Its Ancestors, But Not B’s Ancestors to Reuse AB’s Ancestors to Reuse A

A

B

C

XR

REUSE--62

An Example of Case 1 in FinancialFrameAn Example of Case 1 in FinancialFrame FinancialCompMain FinancialCompMain RR FinancialCompTrader FinancialCompTrader

Thus, Dependencies Between are DesirableThus, Dependencies Between are Desirable Main is Main is not Rnot R to FinancialCompTrader to FinancialCompTrader

Thus, Dependencies Between Hinder ReuseThus, Dependencies Between Hinder Reuse For For “Blue” “Blue” Component, we Don’t Want to Have to Component, we Don’t Want to Have to

Reuse FinancialCompTrader with Main!Reuse FinancialCompTrader with Main!

)(G0Main

FinancialCompMainOtherMain )(G2)(G2

FinancialCompTrader )(G2

R

REUSE--63

Transitivity in Inheritance and Transitivity in Inheritance and Related RelationshipsRelated Relationships

B

A

C

X

R

Case 2Case 2: X is Related to A : X is Related to A Dependencies from X to Dependencies from X to Both A and B are Both A and B are DesirableDesirable

When Reuse X, Since X When Reuse X, Since X Related to B, we Reuse B and Related to B, we Reuse B and All of Its Ancestors (A)All of Its Ancestors (A)

Thus, Dependencies Between Thus, Dependencies Between X and A are Okay!X and A are Okay!

REUSE--64

An Example of Case 2 in FinancialFrameAn Example of Case 2 in FinancialFrame

...

)(G0YieldModel


Bond )(G1

R

Class Bond Class Bond RR to both IndexBond and YieldModel to both IndexBond and YieldModel Thus, Dependencies from Bond to IndexBond and Thus, Dependencies from Bond to IndexBond and

YieldModel are Desirable and Reusable!YieldModel are Desirable and Reusable! When Bond is Reused, So is IndexBond and When Bond is Reused, So is IndexBond and

YieldModel!YieldModel!

REUSE--65

Evaluative Metrics and MethodologyEvaluative Metrics and MethodologyObjective Measures of DependenciesObjective Measures of Dependencies

Object-Oriented Design: Object-Oriented Design: Collection of General and Specific Classes, with Related Characterizations

Recall Dependencies Among ClassesRecall Dependencies Among Classes Object Inclusion: Another Instance within Class Attribute Defn.: Attribute Type of Class Method Invocation: Defined on Another Class

Quantify Dependencies for ReuseQuantify Dependencies for Reuse Good: Promotes Reuse - Leave Alone Bad: Hinders Reuse - Try to Change Okay: No Impact on Reuse - Can be Improved

GoalsGoals Classify and Understand Dependencies Measure Reuse Potential

REUSE--66

Dependencies Among Related ClassesDependencies Among Related Classes Remember, G/S are Subjectively Assigned by Remember, G/S are Subjectively Assigned by

Software DesignerSoftware Designer The Two G classes are Related The Two G classes are Related Related Classes are Intended to be Reused Related Classes are Intended to be Reused

TogetherTogetherGood (1)

G

S

G

SOkay (5)

Okay (7)

Bad (3)

REUSE--67

Sample Dependencies in HTSSSample Dependencies in HTSS

InvCont

DeliIC

Item

DeliItem

Good (1)

Okay (5)

Okay (7)

Bad (3)

InvCont and Item are Related InvCont and Item are Related ClassesClasses

InvCont to Item Dependencies InvCont to Item Dependencies are Good: Reused Togetherare Good: Reused Together

Dependency from InvCont to Dependency from InvCont to DeliItem is ProblemDeliItem is Problem Don’t Want to Reuse

InvCont with DeliItem ManagerGUI with InvCont

Includes Useless DeliItem Dependencies from DeliIC to Dependencies from DeliIC to

Item and/or DeliItemItem and/or DeliItem Don’t Impact Reuse Can Reuse Item and

DeliItem w/o DeliIC

REUSE--68

Dependencies Among Non-Related Dependencies Among Non-Related ClassesClasses

Remember, G/S are Subjectively Assigned by Remember, G/S are Subjectively Assigned by Software DesignerSoftware Designer

The Two G Classes are Not RelatedThe Two G Classes are Not Related Non-Related Classes are Non-Related Classes are NOT NOT Intended to be Intended to be

Reused TogetherReused Together

Okay (6)

Okay (8)

G

S

G

S

Bad (2)

Bad (4)

REUSE--69

Sample Dependencies in HTSSSample Dependencies in HTSS

InvCont

DeliIC

Person

Shopper

Bad(2)

Okay (6)

Okay (8)

Bad (4)

InvCont and Person are Classes InvCont and Person are Classes that are Not Relatedthat are Not Related

InvCont to Person or Shopper InvCont to Person or Shopper Dependencies are BadDependencies are Bad Don’t Want to Reuse

Person/Shopper with InvCont

Must Reuse - Problem! Dependencies from DeliIC to Dependencies from DeliIC to

Person and/or ShopperPerson and/or Shopper Don’t Impact Reuse Can Reuse Person and

Shopper w/o DeliIC However, Poor Design if

DeliIC Needs Person or Shopper!

REUSE--70

Summarizing Couplings ofSummarizing Couplings ofRelated ClassesRelated Classes

Type 1: Good for ReuseType 1: Good for Reuse Two General Classes are Reused Together

Type 3: Bad for ReuseType 3: Bad for Reuse General to Specific To Reuse, Specific Must be Included Added Functionality with No Purpose Change to Type 1 or 5/7

Types 5/7: Okay for ReuseTypes 5/7: Okay for Reuse No Impact Specific Classes Not Reused in New

Application May Improve Reuse if Changed to Type 1

REUSE--71

Summarizing Couplings ofSummarizing Couplings ofNon-Related ClassesNon-Related Classes

Type 2: Bad for Reuse - Two General Classes Type 2: Bad for Reuse - Two General Classes Not Expected to be Reused Together since Not

Related Change to Type 6/8

Type 4: Bad for ReuseType 4: Bad for Reuse General to Specific To Reuse, Specific Must be Included Added Functionality with No Purpose Change to Type 6/8

Types 6/8: Okay for ReuseTypes 6/8: Okay for Reuse No Impact Specific Classes Not Reused in New Application

REUSE--72

Dependencies in Levels of ComponentsDependencies in Levels of ComponentsSummarizing Related ClassesSummarizing Related Classes

0G

1G

2G

0G

1G

2G

(1)

(3)

(3)

0G

1G

2G

0G

1G

2G

(5)

(7)

(7)

0G

1G

2G

0G

1G

2G (1)

(1)

(1)

0G 0GRelated to2G 2GRelated to

REUSE--73

Dependencies in Levels of ComponentsDependencies in Levels of ComponentsSummarizing Non-Related ClassesSummarizing Non-Related Classes

0G

1G

2G

0G

1G

2G

(2)

(4)

(4)

0G

1G

2G

0G

1G

2G

(6)

(8)

(8)

0G

1G

2G

0G

1G

2G (2)

(2)

(2)

Dependencies Among Unrelated Classes AlwaysDependencies Among Unrelated Classes Always Bad for Reuse No Impact on Reuse

REUSE--74

Sample Actions to Improve ReusabilitySample Actions to Improve Reusability

Coupling Among Related Among Unrelated

G G Type (1)Good for Reuse

Type (2)Bad for ReuseMove Src./Dst. to Specific

G S Type (3)Bad for ReuseMove Dst. to General

Type (4)Bad for ReuseMove Src. To Specific

S G Type (5)Can Improve if MoveSrc. to General

Type (6)No Impact on Reuse

S S Type (7) - Can Improveif Move Src./Dst. to Gen.


REUSE--75

Reuse GuidelinesReuse Guidelines Methodological Basis for Increasing ReuseMethodological Basis for Increasing Reuse

Designer Supplies General/Specific/Related for the Classes/Hierarchies in Application

Reuse Analysis Tool Calculates Couplings and Identifies Types of Reuse (Good, Bad, Okay)

Ideal Result: Maximize Reuse via CouplingsIdeal Result: Maximize Reuse via Couplings Type 1: G to G for Related Classes Type 8: S to S for Non-Related Classes

Extended Guidelines: Menu of ChoicesExtended Guidelines: Menu of Choices Different Ways to Move Couplings Considers Impact of Movement on Design

Goal: Iterative Improvement in ReusabilityGoal: Iterative Improvement in Reusability

REUSE--76

Core Guidelines to Move Couplings to Core Guidelines to Move Couplings to Increase Reuse PotentialIncrease Reuse Potential

G

S

G

S

Type 2

Type 8

G

S

G

S

Type 4

Type 8

G

S

G

SType 5

Type 1 G

S

G

SType 7

Type 1

Type 1G

S

G

SType 3

G

S

G

SType 7

REUSE--77

Extended Guidelines for Extended Guidelines for Improving ReusabilityImproving Reusability

Core Guidelines Emphasize Local BehaviorCore Guidelines Emphasize Local Behavior To Remove “Bad” or Improve “Okay” Coupling, To Remove “Bad” or Improve “Okay” Coupling,

Move Cause of the Coupling (e.g., Method Call)Move Cause of the Coupling (e.g., Method Call) Moving a General Method to Specific Class Moving a Specific Method to General Class

Moving Method Up/Down a Hierarchy, Which Moving Method Up/Down a Hierarchy, Which Alters the Coupling, Alters the Coupling, Can Impact ElsewhereCan Impact Elsewhere

Expand the Analyses to Other Couplings of the Expand the Analyses to Other Couplings of the Source and Destination of the Bad Coupling Source and Destination of the Bad Coupling Couplings to Source when Moving Down Couplings to Destination when Moving Up

Extended Guidelines: Menu of ChoicesExtended Guidelines: Menu of Choices

REUSE--78

Extended Guidelines to Improve ReuseExtended Guidelines to Improve ReuseIdentifying the ProblemIdentifying the Problem

S

G

S m()

G G

Type 7

G

S

G

S

Type 3

Type 7

Recall

G

S

G

S

m()G Type 3

Suppose

What has Occurred?

REUSE--79

Extended Guidelines to Improve ReuseExtended Guidelines to Improve ReuseIdentifying the ProblemIdentifying the Problem

S

G

S m()

G G

Type 5

Suppose

What has Occurred?

G

S

G

S

m()G

Type 1

G

S

G

SType 5

Type 1

Recall

REUSE--80

Problem and SolutionProblem and Solution Focus on Core Guidelines May Ignore the Impact Focus on Core Guidelines May Ignore the Impact

of a Change for Other Related and Coupled Classesof a Change for Other Related and Coupled Classes When a Coupling is Moved from a G to S ClassWhen a Coupling is Moved from a G to S Class

Examine All Existing Coupling to G Class G to G Coupling Now G to S We’ve Introduced a “Bad” Coupling

Likewise, When a Coupling Moved from S to G Likewise, When a Coupling Moved from S to G Examine All Existing Coupling to S Class S to S Coupling Now S to G We’ve Introduced a “Bad” Coupling

Solution: Extended Guidelines to Govern all Solution: Extended Guidelines to Govern all Potential Scenarios for Removing “Bad” CouplingsPotential Scenarios for Removing “Bad” Couplings

REUSE--81

Extended Guidelines for Extended Guidelines for Type 3Type 3 Couplings Couplings

Move Coupling Dst. to General ClassMove Coupling Dst. to General Classor Change Dst. To a General Classor Change Dst. To a General Class Type 3 to Type 1 May Introduce Couplings from G

Dst. to Specific Classes Move Coupling Src. to Specific ClassMove Coupling Src. to Specific Class

or Change Src. To a Specific Classor Change Src. To a Specific Class Type 3 to Type 7 May Introduce Couplings from

General Classes to Specific Src. Change to Non-Related/Follow Change to Non-Related/Follow Type 4Type 4 Detailed Evaluation of ImplementationDetailed Evaluation of Implementation Key ConcernsKey Concerns

Local Changes with Global Impact “Wrong” Choice Degrades Reuse

G

S

G

S

Type 3

Among Related

REUSE--82

Removing Removing Type 3Type 3 Couplings in HTSS Couplings in HTSSWhich Changes Make Sense?Which Changes Make Sense?

InvCont

DeliIC

Item

DeliItem

Type 3

Change InvCont to S or DeliItem to GChange InvCont to S or DeliItem to G Neither Makes Sense Against Design Intent!

Move Coupling Dst. to General ClassMove Coupling Dst. to General Class Find Problem Method Call,

Attribute Access, Object Inclusion Move from DeliItem and Item Type 3 to Type 1

Move Coupling Src. to Specific ClassMove Coupling Src. to Specific Class Find Problem Method Call,

Attribute Access, Object Inclusion Move from InvCont and DeliIC Type 3 to Type 7

Detailed Evaluation of ImplementationDetailed Evaluation of Implementation Note: Maintain Application SemanticsNote: Maintain Application Semantics

Type 1

Type 7

REUSE--83


Move Coupling Src. to Specific ClassMove Coupling Src. to Specific Classor Change Src. To a Specific Classor Change Src. To a Specific Class Type 2 to Type 6 May Introduce Couplings from

General Classes to Specific Src. Move Src. and Dst. to Specific ClassesMove Src. and Dst. to Specific Classes

Type 2 to Type 8 May Introduce Couplings from G

Src. to Specific Dst. Move Coupling Dst. to Specific ClassMove Coupling Dst. to Specific Class

or Change Dst. To a Specific Classor Change Dst. To a Specific Class Follow Type 4 Guidelines

Change to Related/Change to Related/Type 1Type 1/Design /Design Impact Must be Evaluated!Impact Must be Evaluated!

Detailed Evaluation of ImplementationDetailed Evaluation of Implementation

G

S

G

S

Type 2

Non-Related

REUSE--84


Move Coupling Dst. to General ClassMove Coupling Dst. to General Classor Change Dst. To a General Classor Change Dst. To a General Class Type 4 to Type 2 - No Help

Move Coupling Src. to Specific ClassMove Coupling Src. to Specific Classor Change Src. To a Specific Classor Change Src. To a Specific Class Type 4 to Type 8 May Introduce Couplings from

General Classes to Specific Src. Change to Related/Follow Change to Related/Follow Type 3Type 3 Detailed Evaluation of ImplementationDetailed Evaluation of Implementation

G

S

G

S

Type 4

Non-Related

REUSE--85

Summary on Extended GuidelinesSummary on Extended Guidelines Total Alternatives for Removing “Bad” Couplings:Total Alternatives for Removing “Bad” Couplings:

Type 2, 3, 4: Seven Possibilities Each: 21 Total Type 5, 7: 3 Total

Changing from G to S or Movement of Coupling Changing from G to S or Movement of Coupling Potential to Impact: Potential to Impact: Couplings to Source Couplings from Destination

Result: Movement May Result: Movement May DecreaseDecrease Reuse Potential! Reuse Potential! Two-Fold Solution:Two-Fold Solution:

Design Support for OO Reuse Metrics and Evaluation within UML, Design Patterns, etc.

Analytical Tool for Evaluating Reuse Potential of C++, Ada95, or Java Applications/Libraries

REUSE--86

Utilizing Reuse MethodologyUtilizing Reuse MethodologyEvaluate Evolving Design/ImplementationEvaluate Evolving Design/Implementation Constructing New ApplicationsConstructing New Applications

Software Design Proceeds in Stages Today’s Norm: Incremental Development and

Rapid Prototyping General/Specific Classes/Related ComponentsGeneral/Specific Classes/Related Components

Assigned Initially as Classes are Generated Refined Throughout Increments/Versions G to S, S to G, etc. Related Components as Design Begins to

Mature with Additional Details Use Methodology to Find/Correct “Problems”

Video Rental System Test-Bed Video Rental System Test-Bed

REUSE--87

Utilizing Reuse MethodologyUtilizing Reuse Methodology Investigate Reusability of Legacy Code Investigate Reusability of Legacy Code

Reusability of Legacy CodeReusability of Legacy Code Examine Legacy Code in Detail Talk/Contact Domain Experts with Corporate

Knowledge of Code General/Specific Classes/Related ComponentsGeneral/Specific Classes/Related Components

Take “Educated Guess” for G/S Classes and Related Components

Run DRE and Find/Correct Problems Re-evaluate Legacy Code with Different

“Educated Guesses” Compare/Contrast Results to Identify the “Best”

way to Characterize Classes/Components See Web Site for Example in FinancialFrameSee Web Site for Example in FinancialFrame

REUSE--88

The Video Rental System (VRS)The Video Rental System (VRS) VRS is for On-Line (Browser) Rental TapesVRS is for On-Line (Browser) Rental Tapes

Maintains Customer and Video Databases Tracks Borrowing/Returning of Tapes Logs Rented Tapes CGI, C++, Netscape/Explorer From Video Rental to Auto Parts Undergraduate Project: Spring 1997 - VRS-1 Repeated as Grad Project: Fall 1998 - VRS-2

Goals:Goals: Demonstrate General/Specific/Related Ideas Incorporate/Reuse Design in Future System Study Effectiveness Approach in Identifying and

Removing Non-Reusable Dependencies

REUSE--89

General and Specific Classes in VRS-1General and Specific Classes in VRS-1

VideoStoreInterface (S)

StoreInterface (G)

VideoCustomer (S)

Customer (G)

VideoCustomerInterface (S)

CustomerInterface (G)

VideoTape (S)

Item (G)

VideoTapeDB (S)

ItemDB (G)

RentedTapeDB (S)RentedTape (S)

CustomerDB (G)

HistoryList (G)

Transaction (G)

REUSE--90

DRE and VRS-1DRE and VRS-1Tracking Incremental VersionsTracking Incremental Versions

Type Metr I II III IV V VI VIIGood CC1 8 54 79 109 166 167 193Bad CC2 0 0 0 0 0 0 0Bad CC3 6 0 0 0 4 4 0Bad CC4 0 0 1 1 0 0 0Impr CC5 0 19 28 39 94 92 75Impr CC6 0 6 6 18 28 30 25Okay CC7 0 0 0 0 0 5 0Okay CC8 0 0 11 11 21 22 26

LOC 410 1386 2088 2695 3784 3824 3867

REUSE--91

Final General/Specific Classes in VRS-2Final General/Specific Classes in VRS-2and Some Related Characterizationsand Some Related Characterizations

VideoStoreInterface (S)

StoreInterface (G)

Customer (G)

CustomerInterface (G)

Video (S)

Item (G)

VideoItemList (S)

ItemList (G) ReportGenerator (S)

Transaction (G)

VideoTransaction (S)

CustomerList (G)

VideoCustList (S)

REUSE--92

DRE and VRS-2DRE and VRS-2Tracking Incremental VersionsTracking Incremental Versions

Type Metr I II III IVGood CC1 17 28 26 26Bad CC2 0 0 0 0Bad CC3 0 0 1 0Bad CC4 0 0 0 0Impr CC5 0 0 2 2Impr CC6 0 0 3 4Okay CC7 0 4 3 3Okay CC8 0 0 0 0

G/SLOCCls.

175/1

325/1

307/6

307/6

REUSE--93

One Type 3 Coupling: G to S DependencyOne Type 3 Coupling: G to S Dependency

Transaction (G)

write_to_checkoutfile()


Customer (G)take_item( )

...tr->calculate_currentdate()tr->calculate_duedate()tr->write_to_historyfile()tr->write_to_checkoutfile()...

calculate_currentdate()calculate_duedate()write_to_historyfile()

• What is the Problem?What is the Problem?• How is it Resolved?How is it Resolved?

REUSE--94

Resolving Type 3 G to S DependencyResolving Type 3 G to S Dependency

Customer (G)take_item( )

Transaction (G)

write_to_checkoutfile()


calculate_currentdate()calculate_duedate()write_to_historyfile()

...tr->calculate_currentdate()tr->calculate_duedate()tr->write_to_historyfile()take_item_specific()...

take_item_specific()

VideoCustomer(S)

((VideoTransaction *) tr) -> write_to_checkoutfile()

REUSE--95







way to Characterize Classes/Components FinancialFrame as a Test-BedFinancialFrame as a Test-Bed

REUSE--96

The FinancialFrame ApplicationThe FinancialFrame ApplicationInitial Assumptions on G/S and RelatedInitial Assumptions on G/S and Related

...

)(G0YieldModel

DiscountIndexBond )(G1 )(G1Bill )(G1

Bond )(G0

FinancialFrame Composed of Multiple Algorithm FinancialFrame Composed of Multiple Algorithm FamilitesFamilites

All Root Classes are G(0) with Subclasses G(1)All Root Classes are G(0) with Subclasses G(1) All Other Classes are G(0)All Other Classes are G(0) Use Actual Couplings in Code to Define Related Use Actual Couplings in Code to Define Related

CharacterizationCharacterization

REUSE--97

Evaluation of FinancialFrameEvaluation of FinancialFramePossible ScenariosPossible Scenarios

Dependencies from to ClassesDependencies from to Classes Occurring from a General Class (Bond) to

Classes Specific to a Component (IndexBond) Such Couplings Require a Specific Class that is

Not Needed to be Reused with the General Root Reported as Undesirable Couplings (Type 3/4)

0G 1G

...

)(G0YieldModel


Bond )(G0

REUSE--98

Revising FinancialFrame ApplicationRevising FinancialFrame Application

...

)(G0YieldModel


Bond )(G1 R

Bond is Changed from to Bond is Changed from to A Component Consisting of Bond, IndexBond, A Component Consisting of Bond, IndexBond,

and YieldModel is Definedand YieldModel is Defined When Bond Reused, So Must IndexBond and When Bond Reused, So Must IndexBond and

YieldModel - Other Classes Not NeededYieldModel - Other Classes Not Needed However, YieldModel can Be Reused in IsolationHowever, YieldModel can Be Reused in Isolation Thus, Modifications to Component Only Affect Thus, Modifications to Component Only Affect

Reusers of ComponentReusers of Component

0G 1G

REUSE--99

Evaluation of FinancialFrameEvaluation of FinancialFramePossible ScenariosPossible Scenarios

Dependencies from to Classes Dependencies from to Classes Occurring from a Specific Class to Other

Classes Specific & Unrelated to a Component Bond Related to Class Outside Component Such Couplings Require a Specific Class in One

Component to be Reused in Another Component, Where it is Not Needed

Reported as Undesirable Couplings (Type 2)

1G 1G

...

)(G0YieldModel


Bond )(G1 R

1G

REUSE--100

Reusability of FinancialFrame Reusability of FinancialFrame ComponentsComponents

Undesirable Couplings Identified via Either Undesirable Couplings Identified via Either Scenario can be Removed to Increase ReuseScenario can be Removed to Increase Reuse

Results of Such Actions w.r.t. FinancialFrameResults of Such Actions w.r.t. FinancialFrame Classes can be Reused with Classes When a Class is Modified, Only Users of

Particular Component(s) are NotifiedBad Coupling No Longer Present!Bad Coupling No Longer Present!

Each Component Can be Reused “As is” Classes Outside of Component No Longer

Needed Cannot Illustrate Due to Proprietary SoftwareCannot Illustrate Due to Proprietary Software Similar Changes to VRS-2 OccurSimilar Changes to VRS-2 Occur

1G1G

0G

REUSE--101

Design Reusability Evaluation (DRE) ToolDesign Reusability Evaluation (DRE) Tool What is DRE?What is DRE?

Java-Based Tool for Analyzing Reusability Takes Java Software as Input Works with General/Specific/Related as

Subjectively Defined by Software Designer Analyzes Couplings to Identify, for Each Type

(1 to 8), the Number of Couplings Allows Designer to Investigate Cause of and

Correct “Bad” or Improve “Okay” Couplings DRE can be Utilized in Different WaysDRE can be Utilized in Different Ways

Evaluate Evolving Design/Implementation Investigate the Reusability of Legacy Code

REUSE--102

The DRE Tool FamilyThe DRE Tool Family

Standard DRE (SDRE)Standard DRE (SDRE) Allows Generality and Related to be Set, and

Metric to be Fired, and Dependencies to be Classified and Analyzed

Directly Edit Source Code for Dependencies Collaborative DRE (CDRE)Collaborative DRE (CDRE)

XML Interoperability to Allow DRE Marking to be Saved and Restored via XML

CDRE Supports Multiple Clients Working on Same Project Simultaneously

Together DRE (TDRE)Together DRE (TDRE) Integrated via Plug-Ins into UML Tool

REUSE--103

Utilizing Reuse MethodologyUtilizing Reuse MethodologyEvaluate Evolving Design/ImplementationEvaluate Evolving Design/Implementation Constructing New ApplicationsConstructing New Applications

Software Design Proceeds in Stages Today’s Norm: Incremental Development and

Rapid Prototyping General/Specific Classes/Related ComponentsGeneral/Specific Classes/Related Components

Assigned Initially as Classes are Generated Refined Throughout Increments/Versions G to S, S to G, etc. Related Components as Design Begins to

Mature with Additional Details Use Methodology to Find/Correct “Problems”

Video Rental System Test-Bed Video Rental System Test-Bed

REUSE--104







way to Characterize Classes/Components FinancialFrame as a Test-BedFinancialFrame as a Test-Bed

REUSE--105

SDRE - Main Application Window SDRE - Main Application Window

REUSE--106

SDRE - SDRE - Main Window – Setting Main Window – Setting GeneralityGenerality

REUSE--107

SDRE - SDRE - Main Window – Setting RelationsMain Window – Setting Relations

REUSE--108

SDRE - SDRE - Main Window – Choosing Main Window – Choosing Simulation OptionsSimulation Options

REUSE--109

SDRE - Help SubsystemSDRE - Help Subsystem

HTML-based Documents Describe Tool & TheoryHTML-based Documents Describe Tool & Theory

REUSE--110

SDRE - Graphical RepresentationSDRE - Graphical RepresentationGenerality Set for DesignGenerality Set for Design

REUSE--111

SDRE - Graphical RepresentationSDRE - Graphical RepresentationSetting Related ClassesSetting Related Classes

REUSE--112

SDRE - Graphical Icons for ClassesSDRE - Graphical Icons for Classes

Relative Edge Base

Inheritance Edge BaseGenerality Base

Base Rectangle

Source File Name

Select Base

Inheritance Edge

Related Edge

REUSE--113

SDRE - Graphical RepresentationSDRE - Graphical Representation

REUSE--114

SDRE - SDRE - Editing Source Code Editing Source Code Enabled When Doubling ClickingEnabled When Doubling Clicking

REUSE--115

SDRE - SDRE - Editing Source CodeEditing Source CodeEditor Appears with Line HighlightedEditor Appears with Line Highlighted

REUSE--116

SDRE - SDRE - Editing Source CodeEditing Source CodeSource Editor FeaturesSource Editor Features

REUSE--117

Collaborative DRE (CDRE)Collaborative DRE (CDRE)

CDRE PurposesCDRE Purposes Enable Teams to Collaborate on Metrics

Measurement Utilize Client/Server Architecture Share Data Between Users Separate Project Information From Class Markings Store Source Code Centrally Execute Metrics on “Powerful” Server Use Same DRE Interface as Control Client

Utilize XML in Redesign Efforts CDRE is Intended to Bring SDRE into a Real-CDRE is Intended to Bring SDRE into a Real-

World Computing EnvironmentWorld Computing Environment

REUSE--118

CDRE – DRE ClientCDRE – DRE Client

REUSE--119

CDRE – Client LoginCDRE – Client Login

REUSE--120

CDRE – Project SelectionCDRE – Project Selection

REUSE--121

CDRE – Remote Class SelectionCDRE – Remote Class Selection

REUSE--122

Together DRE (TDRE)Together DRE (TDRE)

Integrating DRE into TCCIntegrating DRE into TCC Ongoing Prototyping Integrate SDRE into TCC Utilization of TCC Extension Capabilities to

Allow Generality and Related to be Set Initiation of Complete SDRE tool via Plug-In

Capabilities of TCC Single Integrated Design/Development Single Integrated Design/Development

Environment with Reusability AssessmentEnvironment with Reusability Assessment Leverage TCC to Support ReusabilityLeverage TCC to Support Reusability

Incorporate G/S and Related at UML Level Users can Execute Plug Ins for Each Actual Properties for UML Classes Modified Invoke SDRE Directly from TCC

REUSE--123

Reusability in Together CCReusability in Together CC

REUSE--124


REUSE--125


REUSE--126


REUSE--127

Towards the Formalization of a Towards the Formalization of a Reusability Framework for RefactoringReusability Framework for Refactoring

Formal Definitions of Reuse Model to Allow Formal Definitions of Reuse Model to Allow Automatic and Algorithmic Analysis of CouplingsAutomatic and Algorithmic Analysis of Couplings Paper by Cabellero and Demurjian at ICSR-7 OO Application Model Reuse Framework

Coupling Type Transition MatrixCoupling Type Transition Matrix Defines Loss, Gain, or Steady State Between

the Various Coupling Types +1 Going from G-->S to G-->G for Related Classes -1 Going from G-->G to G-->S for Related Classes 0 Going from S-->G to S-->S for Related Classes

REUSE--128

GoalGoal

Increase Reuse Potential by Understanding Increase Reuse Potential by Understanding Classes, Components, and their Role within Classes, Components, and their Role within ApplicationsApplications Identify the Reusable Portions of Design Estimate/Measure Reusability Automatically Provide Guidelines on Improving

Reusability Usable for


Independent Tool/Integrated in Together CC See: http://www.engr.uconn.edu/~steve/DRE/dre.html

REUSE--129

Model of OO ApplicationModel of OO Application

Definition 1: Object-Oriented Application Definition 1: Object-Oriented Application SS is is Modeled As a 3-tuple (Modeled As a 3-tuple (CC, , ii, , mm)) C is the Set of Classes, Where Each

Class Cp Contains a Set Cpm of Methods

Mim Such that Each Method Mi Belongs to Only One Class

I is the Set of Pair-wise Inheritance Relations of Classes in C

M is the Set of Pair-wise Coupling Among Methods

REUSE--130

Model - Pair-wise CouplingsModel - Pair-wise Couplings

Definition 2: Pair-wise CouplingDefinition 2: Pair-wise Coupling Two classes Cp and Cq are Pair-Wise Coupled

when there is at Least One Method miCpM that

Invokes a Method mjCqM .

Cp

m4mim9

m1

m20

Cq

mj

m18m9

m5

REUSE--131

Basis of Reuse FrameworkBasis of Reuse Framework

Class ReusabilityClass Reusability Best Estimate on Potential Utility of Class General: Application Classes that Facilitate

Domain-and-Organization Specific Reuse Specific: Application Classes that are Limited

to use in a Single Application Relations Among ClassesRelations Among Classes

Grouping of Classes that Are Expected to Be Reused Together in Future Applications

REUSE--132

Class ReusabilityClass Reusability

General ClassesGeneral Classes Expected to be Reused in Future Applications Abstract Classes/Root Classes/Non-Leaf

Classes in Inheritance Hierarchies Domain Independent/Domain Specific

Specific ClassesSpecific Classes Only Applicable in Current Applications Unlikely to be Reused in Future Applications Application Specific

Purpose: Determine Classes with Highest Reuse Purpose: Determine Classes with Highest Reuse Potential for Organization’s Future SystemsPotential for Organization’s Future Systems

REUSE--133

Model - Class ReusabilityModel - Class Reusability

Definition 3: The Definition 3: The Reusability LevelReusability Level of Class of Class CCii is is Denoted by Denoted by GGccii

Gci=0 Ci is the Most General Class in the Application

Gci=N (N>0) Ci is the Most Specific Class in the Application

Lower N, More General Class Class Generality VectorClass Generality Vector

Cn

Ci

C

G

G

G

G

1

REUSE--134

Model - Relations Among ClassesModel - Relations Among Classes

Related Classes Promote Reuse, Since They are Related Classes Promote Reuse, Since They are Expected to be Reused Together Expected to be Reused Together Class Ci is Related to Class Cj if Expected to be

Reused Together in Future Systems Class Ci Related to Class Cj is Subjectively

Assigned by Software Engineer (Producer) Related Classes Assist in Reusability AssessmentRelated Classes Assist in Reusability Assessment

REUSE--135

Quantifying Reuse PropertiesQuantifying Reuse Properties

Property 1: Generality and InheritanceProperty 1: Generality and Inheritance Parent of a Class is Equally General or More

General than is Direct Children Property 2: Generality and Related ClassesProperty 2: Generality and Related Classes

Reuse Level of Class is Equal to the Reuse Level of the Least Reusable Coupled Class

Property 3: Extraneous FunctionalityProperty 3: Extraneous Functionality Classes that Don’t Contribute to Functionality

of Component have Negative Impact on Reuse Property 4: Generality and Unrelated ClassesProperty 4: Generality and Unrelated Classes

Couplings Between Unrelated Classes Hinder Reuse

REUSE--136

Dependencies Among ClassesDependencies Among Classes

Object Inclusion: Object Inclusion: Class Contains a Instance of Class Contains a Instance of Another ObjectAnother Object

Attribute Definition: Attribute Definition: Class Contains Attribute that Class Contains Attribute that is the Type of Another Objectis the Type of Another Object

Method Invocation: Method Invocation: Class Invokes a Method Class Invokes a Method Defined on Another ObjectDefined on Another Object

GoalsGoals Classify and Understand Dependencies Assess “Good” vs. “Bad” Dependencies Change “Bad” to “Good” by

Changing Class from S to G or G to S Moving Code and/or Method Calls Splitting a Class into Two Classes Merging Two Classes

REUSE--137

Dependencies: Related ClassesDependencies: Related Classes Remember, G/S are Subjectively Assigned by Remember, G/S are Subjectively Assigned by

Software DesignerSoftware Designer The Two G classes are Related The Two G classes are Related Related Classes are Intended to be Reused Related Classes are Intended to be Reused

TogetherTogether

Good (Type 1)G

S

G

S

Okay (Type 5)

Okay (Type 7)

Bad (Type 3)

REUSE--138

Dependencies: Non-Related ClassesDependencies: Non-Related Classes G/S are Subjectively Assigned by DesignerG/S are Subjectively Assigned by Designer The Two G Classes are Not RelatedThe Two G Classes are Not Related Non-Related Classes are Non-Related Classes are NOT NOT Intended to be Intended to be

Reused TogetherReused Together

Okay (Type 6)

Okay (Type 8)

G

S

G

S

Bad (Type 2)

Bad (Type 4)

REUSE--139

Sample Actions to Improve ReusabilitySample Actions to Improve Reusability

Coupling Among Related Among Unrelated

G G Type (1)Good for Reuse

Type (2)Bad for ReuseMove Src./Dst. to Specific

G S Type (3)Bad for ReuseMove Dst. to General

Type (4)Bad for ReuseMove Src. To Specific

S G Type (5)Can Improve if MoveSrc. to General


S S Type (7) - Can Improveif Move Src./Dst. to Gen.


REUSE--140

Core Guidelines to Move Couplings to Core Guidelines to Move Couplings to Increase Reuse PotentialIncrease Reuse Potential

G

S

G

S

Type 2

Type 8

G

S

G

S

Type 4

Type 8

G

S

G

SType 5

Type 1 G

S

G

SType 7

Type 1

Type 3G

S

G

SType 7

Type 1G

S

G

SType 3

REUSE--141

Coupling Type TransitionsCoupling Type Transitions

Defines Loss, Gain, or Steady State Between the Defines Loss, Gain, or Steady State Between the Various Coupling TypesVarious Coupling Types

For Example, For Example, Going from a GS to a GG Coupling Type

for Related Classes is a +1 Going from a GG to a GS Coupling Type

for Related Classes is a -1 Going from a SG to a SS Coupling Type

for Related Classes is a 0 Define a Matrix for all Transitions Among the Define a Matrix for all Transitions Among the

Eight Coupling Types in One StepEight Coupling Types in One Step Distinguish Related from Unrelated TransitionsDistinguish Related from Unrelated Transitions

REUSE--142

Coupling TransitionsCoupling Transitions

Related Classes

Unrelated Classes

REUSE--143

Reuse Improvement FactorReuse Improvement Factor

Metric of the Loss, Gain, or Steady State Between Metric of the Loss, Gain, or Steady State Between the Various Coupling Types After the Refactoringthe Various Coupling Types After the Refactoring

Defined byDefined by

where where is the Matrix for all Transitions Among the is the Matrix for all Transitions Among the Eight Coupling Types in One StepEight Coupling Types in One Step If > 0 Refactoring had Negative Reuse

Impact If < 0 Refactoring had Positive Reuse

Impact If = 0 Refactoring had No Impact on Reuse

n

i

n

jtt ijij

0 0]~][[

REUSE--144

Motivation of Refactoring AlgorithmMotivation of Refactoring Algorithm

Goal: Improve the Reuse Potential of an Goal: Improve the Reuse Potential of an ApplicationApplication

Formalizes Guidelines to Increase Reusability Formalizes Guidelines to Increase Reusability Introduced by M. Price and S. DemurjianIntroduced by M. Price and S. Demurjian

Basic IdeaBasic Idea Analyze All Couplings that Can be Improved Refactor Application Automatically Evaluate the Impact on Reuse of Refactoring

Commit if “Reuse Improvement Factor” is Positive Undo if “Reuse Improvement Factor” is Negative

Iterate until All Appropriate Couplings Considered

REUSE--145

Refactoring AlgorithmRefactoring Algorithm

Step 1: Step 1: Identify Reuse Potential - Mark GeneralitiesIdentify Reuse Potential - Mark GeneralitiesStep 2: Step 2: Calculate CouplingsCalculate CouplingsStep 3: Step 3: Identify Related ClassesIdentify Related ClassesStep 4: Step 4: Determine Coupling TypesDetermine Coupling TypesStep 5: Step 5: Identify Undesirable CouplingsIdentify Undesirable CouplingsStep 6: Step 6: Refactor: Move Source or Destination Method, Refactor: Move Source or Destination Method,

Change Reuse Level, Related to UnrelatedChange Reuse Level, Related to UnrelatedStep 7: Step 7: Recalculate Reuse Improvement FactorRecalculate Reuse Improvement Factor

Step 8: Step 8: If Reuse Factor <= 0 Goto If Reuse Factor <= 0 Goto Step 6Step 6 Else Goto Else Goto Step Step 55 or Terminate Based on Condition or Terminate Based on Condition

n

i

n

jtt ijij

0 0]~][[

REUSE--146

Example - AssumptionsExample - Assumptions

Assume Classes: CAssume Classes: C11, C, C22, C, C33, C, C44, C, C55, C, C66, C, C77 Methods: mMethods: m11, m, m22, m, m33, m, m44, m, m55, m, m66, m, m77, m, m88 Dependencies Among Methods (Couplings) Dependencies Among Methods (Couplings)

Shown with ArrowsShown with Arrows

REUSE--147

Example - Generality and RelatedExample - Generality and RelatedSteps 1, 2, 3 of AlgorithmSteps 1, 2, 3 of Algorithm

G G G G

S

SS

Establish Class ReusabilityEstablish Class Reusability C1, C2, C4, C6 General C3, C5, C7 Specific

Calculate CouplingsCalculate Couplings Assume all Classes are Related Classes to One Assume all Classes are Related Classes to One

AnotherAnother

REUSE--148

G G G G

S

SS

Example - Determine Coupling TypesExample - Determine Coupling TypesStep 4 of AlgorithmStep 4 of Algorithm

REUSE--149

G G G G

S

SS

Example - Identify Undesirable CouplingsExample - Identify Undesirable Couplings Step 5 of Algorithm Step 5 of Algorithm

REUSE--150

Example - Refactor the ApplicationExample - Refactor the Application Step 6 of Algorithm Step 6 of Algorithm

For (mFor (m33,m,m55) Try to Move Source Method Down) Try to Move Source Method Down

m3

0000000000000000000000000500000030300010000700000000000000000300

~T 011 No Improvement!

REUSE--151


For (mFor (m44,m,m66) Try to Move Source Method Down) Try to Move Source Method Down

m4

0000000000000000000000000500000070700050000300000000000000000100

~T 1111 Commit the ChangesSet T=T

~

REUSE--152


For (mFor (m55,m,m77) try to Move Source Method Down) try to Move Source Method Down

m4

0000000000000000000000000100000070700050000100000000000000000100

~T 211

m5

Commit the ChangesSet T=T

~

REUSE--153

Example - Refactored Class DiagramExample - Refactored Class Diagram

G G G G

SS

S

REUSE--154

Reusability and UMLReusability and UML Investigation of Our Reuse Model and Framework Investigation of Our Reuse Model and Framework

at Design Level via UMLat Design Level via UML Establishing Generality and Related in Use-

Case and Class Diagrams Counting and Tracking Dependencies in

Behavior Modeling and Component Diagrams Key QuestionsKey Questions

Can Use Cases have Generality Levels? How Do UC Generalities Relate to Classes? What Dependencies Can be Tracked for Either

Warning or Counting (Metrics)? Incorporation into TCC and Transition to DRE

Build and Extend the Formal Model (Caballero)Build and Extend the Formal Model (Caballero)

REUSE--155

Revisiting Reuse PropertiesRevisiting Reuse Properties

Property 1: Generality and InheritanceProperty 1: Generality and Inheritance Parent of a Class is Equally General or More

General than is Direct Children Property 2: Generality and Related ClassesProperty 2: Generality and Related Classes

Reuse Level of Class is Equal to the Reuse Level of the Least Reusable Coupled Class

Property 3: Generality and Unrelated ClassesProperty 3: Generality and Unrelated Classes Couplings Between Unrelated Classes Hinder

Reuse

REUSE--156

Reuse Definition, Assessment, and Reuse Definition, Assessment, and Analysis in UMLAnalysis in UML

Examination of Reuse in …Examination of Reuse in … Use Case Diagrams Class Diagrams Behavior Modeling Diagrams Component Diagrams

Reuse Improvement During DesignReuse Improvement During Design Transition from Design into DevelopmentTransition from Design into Development Consistency of Approach with Existing Reuse Consistency of Approach with Existing Reuse

Model and Formal Refactoring GuidelinesModel and Formal Refactoring Guidelines Definite Additional Properties (see Previous Slide)Definite Additional Properties (see Previous Slide) Introduce Introduce Refactoring Guidelines Refactoring Guidelines that Enforce the that Enforce the

Properties of Reuse for UML DiagramsProperties of Reuse for UML Diagrams

REUSE--157

Reuse Definition, Assessment, and Reuse Definition, Assessment, and Analysis in UMLAnalysis in UML

Examination of Reuse in …Examination of Reuse in … Use Case Diagrams Class Diagrams Behavior Modeling Diagrams Component Diagrams

Reuse Improvement During DesignReuse Improvement During Design Transition from Design into DevelopmentTransition from Design into Development Consistency of Approach with Existing Reuse Consistency of Approach with Existing Reuse

Model and Formal Refactoring GuidelinesModel and Formal Refactoring Guidelines Definite Additional Properties (see Previous Slide)Definite Additional Properties (see Previous Slide) Introduce Introduce Refactoring Guidelines Refactoring Guidelines that Enforce the that Enforce the

Properties of Reuse for UML DiagramsProperties of Reuse for UML Diagrams

REUSE--158

Use Cases with GeneralitiesUse Cases with Generalities Application has Three Application has Three

Systems Systems Each System with One or Each System with One or

More Use CaseMore Use Case Each Use Case has Each Use Case has

Generality LevelGenerality Level Relationships Among Relationships Among

Use Cases are:Use Cases are: Extend Include Generalize

Generalities Must be Generalities Must be Consistent within Consistent within Systems and Between Systems and Between UCs Given RelationshipsUCs Given Relationships

REUSE--159

Use Cases with Use Cases with Include, Extend, and InheritanceInclude, Extend, and Inheritance

Dependencies Among Use CasesDependencies Among Use Cases Dependencies are Transitive w.r.t. GeneralitiesDependencies are Transitive w.r.t. Generalities

REUSE--160

Properties for Use CasesProperties for Use Cases

Property 4: Property 4: UCUCAA extends UC extends UCBB means UC means UCAA adds adds behavior to UCbehavior to UCBB, so UC, so UCAA is at most as general as UC is at most as general as UCBB or Gor GUC-B UC-B G GUC-AUC-A

Property 5: Property 5: UCUCAA includes UC includes UCBB is a relation of the is a relation of the

behavior sequence of supplier UCbehavior sequence of supplier UCBB to the interaction to the interaction

sequence UCsequence UCAA. Thus, UC. Thus, UCAA is at most as general as is at most as general as

UCUCBB or G or GUC-B UC-B G GUC-AUC-A.. Property 6: Property 6: UCUCAA generalizes UC generalizes UCBB relates child UC relates child UCBB to to

parent UCparent UCAA, meaning that UC, meaning that UCBB is at most as general as is at most as general as UCUCAA or G or GUC-AUC-A G GUC-BUC-B..

REUSE--161

Corresponding Refactoring GuidelinesCorresponding Refactoring Guidelines

RG1 or RG2 to Enforce Property 4 or Property 5:RG1 or RG2 to Enforce Property 4 or Property 5: The refactoring rule is: If GUC-B > GUC-A then

refactor by making UCB more general (or UCA more specific) so GUC-B GUC-A or by removing the extend/include.

RG3 to Enforce Property 6:RG3 to Enforce Property 6: The refactoring rule is: If GUC-A > GUC-B then

refactor by making UCA more general (or UCA more specific) so GUC-A GUC-B or or by removing the generalization.

REUSE--162

Identifying ProblemsIdentifying ProblemsRG3 for Pay CashRG3 for Pay Cash

RG2 for Place Order: to G2 or Remove <include>RG2 for Place Order: to G2 or Remove <include> RG3 for Pay Cash: to G1 or Arrange Payment to RG3 for Pay Cash: to G1 or Arrange Payment to

G0 or Remove <generalization>G0 or Remove <generalization>

REUSE--163

UML Reuse and Class DiagramsUML Reuse and Class Diagrams Definition 3:Definition 3:

UCA is related to ℭA = {C1 , C2 , …, Cn } for some n, if UCA relies on ℭA for functionality.

Property 7: UCs and Classes - GeneralityProperty 7: UCs and Classes - Generality Suppose UCA has ℭA = {C1 , C2 , …, Cn }. Then, the generality

of UCA must be as specific as the most specific class in ℭA , and may be more specific, i.e., GUC-A = max{generality Ci ℭA }.

RG4 to Enforce Property 7RG4 to Enforce Property 7 The refactoring rule is: generality change of UCA or one or

more Ci in ℭA until GUC-A = max{generality Ci ℭA }, or the removal of all classes in ℭA that cause the GUC-A = max{generality Ci ℭA } to be violated.

REUSE--164

Classes and Generality Levels Classes and Generality Levels

CPlace Order ={Order Container, Order, ItemDB } COrder Product = {Item }COrder Computer ={Computers } C- Order Car = {Cars } CRequest Catalog ={Catalog }CSupply Customer Data = {Customer, DB Access } CArrange Payment = {Payment }

REUSE--165

UML Reuse and Class DiagramsUML Reuse and Class Diagrams

Property 8: UCs and Classes - RelatedProperty 8: UCs and Classes - Related Suppose that UCA is related to ℭA and UCB is

related to ℭB . If UCA is related to UCB (extend, include, or generalize), then there has to be at least one transitive relation chain from one Ci ℭA to one Cj ℭB.

RG5 to Enforce Property 8RG5 to Enforce Property 8 The refactoring rule is: Add one or more

dependencies between class(es) Ci ℭA and class(es) Cj ℭB, or remove the relation between UCA and UCB

REUSE--166

UML Reuse and Class DiagramsUML Reuse and Class Diagrams Property 9: UCs to UCs - RelatedProperty 9: UCs to UCs - Related

Suppose that UCA is related to ℭA and UCB is related to ℭB , and that UCA is not related to UCB (there is not an extend, include, or generalize). Then, if at least one Ci ℭA is directly related (meaning not by transitive relation chain) to at least one Cj ℭB, there must be a refactoring to correct the problem.

RG6 to Enforce Property 9RG6 to Enforce Property 9 The refactoring rule is: make UCA related to UCB or

remove all dependencies between all Ci ℭA and all Cj ℭB.

REUSE--167

UML Reuse and Class DiagramsUML Reuse and Class Diagrams Property 10: UCs and Classes - RelatedProperty 10: UCs and Classes - Related

Suppose that UCA is related to ℭA. Then for all Ci ℭA , if there is a transitive relation chain from Ci to some Cj ℭA, then UCA must also be related to Cj in some manner. UCA can be either related directly to Cj or it can be related to some UCB, to which Cj is related

RG7 to Enforce Property 10RG7 to Enforce Property 10 The refactoring rule is: Ci ℭA related to some Cj ℭA include Cj in ℭA (ℭA= ℭA Cj), or relate UCA to some UCB where Cj ℭB, or unrelate UCA to Ci (ℭA= ℭA - Cj).

REUSE--168

Refactored UC Diagram Refactored UC Diagram from Earlier Slide from Earlier Slide

REUSE--169

UML Reuse and Behavior DiagramsUML Reuse and Behavior Diagrams

Sequence and Collaboration Diagrams Can Sequence and Collaboration Diagrams Can Also Impact on Reuse - Why?Also Impact on Reuse - Why? Both Alter Dependencies Introduce/Remove Associations

For Example:For Example: Sequence Diagram Can Introduce New

Dependencies Among Classes (ℭ Sets) Collaboration Diagram Could Also

Introduce Similar Dependencies that Require Refactoring

See Paper for Details

REUSE--170

UML Reuse and Component DiagramsUML Reuse and Component Diagrams

Definitions for UML ComponentsDefinitions for UML Components Definition 4: Component and Classes that

Implement it Definition 5: Component and Façade that hides

Implementation Details Definition 6: Component and Abstract

Classes/Interfaces Accompanying Properties/Refactoring GuidelinesAccompanying Properties/Refactoring Guidelines

Property 11/RG8 - Components vs. Classes Property 12/RG9 - Component vs. Component Property 13/RG10 - Component vs. Façade

See Section 3.4 of Paper for Further Details See Section 3.4 of Paper for Further Details

REUSE--171

Modifications to Together CCModifications to Together CC

Leverage Open APIs and Plug In Structure to Leverage Open APIs and Plug In Structure to Incorporate Reuse Model for UML into TCCIncorporate Reuse Model for UML into TCC

Multi-Phase ApproachMulti-Phase Approach Directly Extend Property Windows of Use

Cases and Classes for Generality Definition Augment with new Window for Related Add New Metrics Pane that Supports Analysis

as Presented (Definitions, Properties, and RGs) Briefly, we’ll Review ModificationsBriefly, we’ll Review Modifications Please See Web Site for Full DetailsPlease See Web Site for Full Details

REUSE--172

Setting Project OptionsSetting Project Options

REUSE--173

UC: Generality and RelatedUC: Generality and Related

REUSE--174

Classes: Generality and Related Classes: Generality and Related

REUSE--175

Components and FacadesComponents and Facades

REUSE--176

Running DRE and MetricsRunning DRE and Metrics

REUSE--177

Analyzing Reuse and RefactoringAnalyzing Reuse and Refactoring Affected ElementsAffected Elements: Elements affected by warning. : Elements affected by warning. Description: Provides a description of the warning Refactoring Guideline: One or more refactoring

guidelines for the currently selected warning

REUSE--178

TCC: DRE-UML WarningsTCC: DRE-UML Warnings

Use Case Diagrams: Generalities and Related Classes Dependencies to other Use Cases (include,

extend, generalize) Class Diagrams:

Generalities and Related Classes Dependencies to other Classes (association,

dependency, generalization) Sequence/Collaboration Diagrams: Method Calls Component Diagrams:

Related and Façade Classes Implemented Interfaces Dependencies of Components and Interfaces

REUSE--179

ConclusionsConclusions

Comprehensive Reusability Model and EvaluationComprehensive Reusability Model and Evaluation General/Specific/Related Characterizations Capture/Analyze Reusability of OO Software Design Level (UML) and Code Level (DRE) Achieve Highest Gain Through Early

Identification and Reusability Evaluations! Methodology and Empirical VerificationMethodology and Empirical Verification

Guidelines to Encourage Reuse Applicable to Reuse of Designs and Code DRE Tool Family: SDRE, CDRE, TDRE Strong Demonstration of

Domain-and-Organization-Specific Reuse

REUSE--180

Future Work - Reusability - SummaryFuture Work - Reusability - Summary

Possible Short/Long-Term ResearchPossible Short/Long-Term Research Focus on Comprehensive Reuse Framework Guided Reusability Assessment/GA Analysis Component Repository with Search Capability Leverage Domain/Organization Specificity XML and Java Components

REUSE--181

Genetic Algorithm and ReuseGenetic Algorithm and Reuse

Towards Towards Guided Software Reusability AssessmentGuided Software Reusability Assessment Multi-Step Iterative Process:Multi-Step Iterative Process:

Determine Set of Assumptions Regarding Generality Levels of Generality that are Required Related Implied by Dependencies or Set by User

Key Issue is to Define Constraints that Will Underlie the GA Fitness Function

Run the Genetic Algorithm on Code for Fixed Population and Number of Generations

Evaluation of Results - Potential to Rerun with Changed Assumptions, Population, Generations

Converge Towards “Reasonable” Marking

REUSE--182

Future: Formal Reuse ModelFuture: Formal Reuse Model

Future Work Future Work Exploring Weightings (+2, +3, -3, etc.) for

Transitions Among Coupling Types Explore and Refine the Reuse ModelExplore and Refine the Reuse Model

Theoretical Verification of Reuse Model Use of GA to Obtain “Near” Optimal Marking

Practical PerspectivePractical Perspective Integrating Metric and Model in SDRE Testing with “Real” Examples and Prior

Examples