Everyone has heard the old saying about the shoemaker's children: The shoemaker is so busy making shoes for others that his children don't

have shoes of their own. Prior to the 1990s, many software developers were the "shoemaker's

children." Although these technical professionals built complex systems and products that

automated the work of others, they used very little automation themselves.

Today, software engineers have their first new pair of shoes—computer-aided software

engineering (CASE).

Computer Aided Systems Computer Aided Systems Engineering (CASE)Engineering (CASE)

CASE is the application of computer technology to systems development activities, techniques, and methods.

COMPUTER-AIDED SOFTWARE ENGINEERING (CASE)

The automation of step-by -step methodologies for software and systems development

CASE tools automate or support one or more phases of the SDLC to speed up development and improve quality.

What Is a CASE Tool? Since the early days of writing software, there has been an awareness of the need for automated tools to help the software developer. Initially the concentration was on program support tools such as translators, compilers, assemblers, macro processors, and linkers and loaders. However, as computers became more powerful and the software that ran on them grew larger and more complex, the range of support tools began to expand. In particular, the use of interactive time-sharing systems for software development encouraged the development of program editors, debuggers, code analyzers.

A CASE tool is a computer-based product aimed at supporting one or more software engineering activities within a software development process.

Computer-aided software engineering (CASE) is the use of software tools to assist in the development and maintenance of software. Tools used to assist in this way are known as CASE Tools.

Some typical CASE tools are: Code generation tools Data modeling tools UML Refactoring tools QVT or Model transformation Tools Configuration management tools including

revision control

All aspects of the software development lifecycle can be supported by software tools, and so the use of tools from across the spectrum can, arguably, be described as CASE; from project management software through tools for business and functional analysis, system design, code storage, compilers, translation tools, test software, and so on.

Computer AidedComputer AidedSystems EngineeringSystems Engineering

(CASE)(CASE)

aims to improve quality of systems focuses on automating structured techniques

– upper CASE tools– lower CASE tools

relies on rigorous development methods

CASE FrameworkCASE Framework

Planning SupportImplementationDesignAnalysis

CASE ToolsCASE Tools

upper-CASE lower-CASE cross life cycle CASE

Upper CASE ToolsUpper CASE Tools

systems planning– goals, objectives– business models

systems analysis– scope, boundaries– detailed modeling– prototyping

Lower CASE ToolsLower CASE Tools

systems design– technology models

systems implementation– programmer workbench– code generation

systems support– reverse engineering– REVERSE ENGINEERING– The process of examining an existing application that has

characteristics that are similar to a desired application. Using the existing application as a guide, the requirements for the new application are defined, analyzed, and extracted all the way back tospecifications. From this point, the specifications are altered to comply with any new customer requirements and the new application is developed.

Cross Life Cycle Cross Life Cycle CASE ToolsCASE Tools

project management process management estimation documentation

ProductionSystem

TechnicalDesign

BusinessRequirements

Existing System Planned ProjectPlanning

Support

Implementation Design

Analysis

Automated process support (CASE)Automated process support (CASE)

Computer-aided software engineering (CASE) is software to support software development and evolution processes

Activity automation– Graphical editors for system model development

– Data dictionary to manage design entities

– Graphical UI builder for user interface construction

– Debuggers to support program fault finding

– Automated translators to generate new versions of a program

Case technologyCase technology

Case technology has led to significant improvements in the software process though not the order of magnitude improvements that were once predicted– Software engineering requires creative thought -

this is not readily automatable– Software engineering is a team activity and, for

large projects, much time is spent in team interactions. CASE technology does not really support these

CASE classificationCASE classification

Classification helps us understand the different types of CASE tools and their support for process activities

Functional perspective– Tools are classified according to their specific function

Process perspective– Tools are classified according to process activities that

are supported

Integration perspective– Tools are classified according to their organisation into

integrated units

Functional tool classificationFunctional tool classification

Activity-based classificationActivity-based classification

Reengineering tools

Testing tools

Debugging tools

Program analysis tools

Language-processingtools

Method support tools

Prototyping tools

Configurationmanagement tools

Change management tools

Documentation tools

Editing tools

Planning tools

Specification Design Implementation Verificationand

Validation

CASE integrationCASE integration

Tools– Support individual process tasks such as design

consistency checking, text editing, etc.

Workbenches– Support a process phase such as specification or

design, Normally include a number of integrated tools

Environments– Support all or a substantial part of an entire software

process. Normally include several integrated workbenches

Tools, workbenches, environmentsTools, workbenches, environments

Single-methodworkbenches

General-purposeworkbenches

Multi-methodworkbenches

Language-specificworkbenches

Programming TestingAnalysis and

design

Integratedenvironments

Process-centredenvironments

Filecomparators

CompilersEditors

EnvironmentsWorkbenchesTools

CASEtechnology

CASE RepositoryCASE Repository

a developers database– stores diagrams, specifications, code– ensures standardization, consistency– tracks people, data, process, network, technology

stored– locally– in work groups– centrally

Computer-Aided System Engineering (CASE)Computer-Aided System Engineering (CASE)

CASE tools: Software tools designed to help system analyst complete development tasks

The CASE tool contains a database of information called a repository

Information about models

Descriptions

Data definitions

References that link models together

Case tools can check the models to make sure they are complete and follow diagramming rules

Also can check if the models are consistent

Adds a number of capabilities around the repository

CASE Approach (cont.)CASE Approach (cont.)

A CASE tool repository contains all information about the system.

Types of CASE toolsTypes of CASE tools

Upper CASE toolsSupport analyst during the analysis and design phases

Lower CASE toolsSupport for implementation – e.g. generating programs

Tools may be general, or designed for specific methodology (like for information engineering – TIs’ IEF, CoolTools)Examples of CASE tools

Visual Analyst for creating traditional modelsCalled “integrated application development tool”

Rational Rose for object-oriented modelingBased on UML standard for object orientationAllows for reverse-engineering and code generation (can be integrated with other tools like Visual C++ etc.)

“Round trip engineering” – synchronized updating

Types of CASE tools (cont.)Types of CASE tools (cont.)

The CASE tool Visual Analyst showing a data flow diagram.

Types of CASE tools (cont.)Types of CASE tools (cont.)

The visual modeling tool Rational Rose showing diagrams from the object-oriented approach

Types of CASE tools (cont.)Types of CASE tools (cont.)

he round-trip engineering tool Together J showing a class diagram with synchronized Java source code.

What CASE can do to helpWhat CASE can do to help

Help to make analysis and design process more rigorous and complete, to reduce bugs later

Examples of functions in tools:Provide support for diagramming (for analysis and design)

Provide support for checking consistency of design

Provide graphing support to help users visualize an existing or proposed information system (e.g. Data flow diagrams)

Detail the processes of your system in a hierarchical structure

Produce executable applications based on your data flow diagrams (which can be made from point and click placements of icons)

Integrate specific methodologies into windowing environments

Evolution of Software ToolsEvolution of Software Tools

Assemblers

Compilers

Debuggers

CASE-Analysis +Design

CASE-Code generators

soph

isti

cati

on

Current Status of CASECurrent Status of CASE

A number of commercial productsSome aspects (e.g. diagramming support) are widely applicable and usefulOther features such as code generation are more specific

CASE tools not so successful for generic code generationHowever, specific code generation is now being used for things such as user interface design (e.g. Visual C++ allows you to “draw” the interface and it generates the code)

As ideas become successful often no longer called CASE

Causes of failure (and symptoms) in software developmentCauses of failure (and symptoms) in software development

Requirements AnalysisNo written requirementsIncompletely specified requirementsNo user interface mock-upNo end –user involvement (can happen – may have talked to clients BUT not users!)

DesignLack of, or insufficient, design documentsPoorly specified data structures and file formatsInfrequent or no design reviews

Causes of failure (and symptoms) in software development Causes of failure (and symptoms) in software development (cont.)(cont.)

ImplementationLack of, or insufficient coding standards

Infrequent or no code reviews

Poor in-line code documentation

Unit test and IntegrationInsufficient module testing

Lack of proper or complete testing

Lack of an independent quality assurance group

Causes of failure (and symptoms) in software development Causes of failure (and symptoms) in software development (cont.)(cont.)

Beta Test ReleaseComplete lack of a beta test

Insufficient duration for beta test

Insufficient number of beta testers

Wrong beta testers selected

MaintenanceToo many bug reports

Fixing one bug introduces new bugs

Stats on Software Errors (large systems)Stats on Software Errors (large systems)

Most software errors originate in the Analysis and Design phases (65%)

Unfortunately, less than one-third of these errors are caught before acceptance testing begins

About 35% of errors occur during coding Cost of fixing an error goes up the later it is caught! This is basis for emphasis in CASE on Analysis and

Design

CASE Facilities and FunctionsCASE Facilities and Functions

graphics facilities description facilities prototyping inquiry and reporting quality assurance decision support

documentation transform

generators data sharing security, version control housekeeping

CASE Tool IntegrationCASE Tool Integration

data integration– file transfer, linkage, or central interface

presentation integration– Windows, Motif, etc.

tool integration– interoperation

ProductionSystem

TechnicalDesign

BusinessRequirements

Existing System Planned ProjectPlanning

Support

Implementation Design

Analysis

CASE WorkbenchCASE Workbench

Planning SupportImplementationDesignAnalysis

Benefits of CASEBenefits of CASE

Increased Productivity Improved Quality Better Documentation Reduced Lifetime Maintenance Methods that really work

Costs of CASECosts of CASE

hardware and systems software training and consulting justification for CASE

Implementation Implementation RecommendationsRecommendations

get your methods in order select right people develop reasonable expectations choose appropriate pilot create support mechanism learn from others continually improve

CASE toolsCASE tools

Upper CASE tools: support for the analysis and design

Lower CASE tools: support for construction and maintenance

1980s…

Nowadays…

Integrated CASE tools: Offer extensive life cycle coverage

CASE tools: Automated Diagram CASE tools: Automated Diagram Support Support

Checks for syntactic correctness Data dictionary support Checks for consistency and completeness Navigation to linked diagrams Layering Requirements traceability Automatic report generation System simulation Performance analysis

CASE tools: Software construction CASE tools: Software construction and maintenanceand maintenance

Code generators…Generate code from the design model…Think of the advantages!…may also generate database schemata…

Maintenance tools Reverse Engineering Analysis of program code

CASE tools: AdvantagesCASE tools: Advantages

Help standardization of notations and diagrams Help communication between development team members Automatically check the quality of the A&D models Reduction of time and effort Enhance reuse of models or models’ components

CASE tools: DisadvantagesCASE tools: Disadvantages

• Limitations in flexibility of documentation• May lead to restriction to the tool’s capabilities• Major danger: completeness and syntactic correctness does NOT mean compliance with requirements• Costs associated with the use of the tool: purchase + training

UML: History and UML: History and Brief Summary Brief Summary

Adoption of the OO paradigm … problematic

Emergence of UML as a methods’ unification approach

UML notation: a melding of graphical notationsfrom various sources.

+ other concepts…

UML: An OMG standard since 1997…Under way to become an ISO standard!

UML: History and UML: History and Brief Summary Brief Summary

UML: A method or a notation?

Primarily a notation

Modeling method: techniques + guidelines + notations roadmap for the development of a model

However, there are attempts to describe OO methods or methodological frameworks that would be able to employ UML.

• The Rational Unified Process• The Object-oriented Process, Environment and Notation (OPEN)