CASE

CASE (Computer Aided Software Engineering)

What is it? Computer-aided software engineering (CASE) tools assist software engineering managers and practitioners in every activity associated with the software process. They automate project management activities, manage all work products produced throughout the process, and assist engineers in their analysis, design, coding and test work. CASE tools can be integrated within a sophisticated environment.

Who does it do? Project managers and software engineers use CASE.

Why is it important? Software engineering is difficult. Tools that reduce the amount of effort required to produce a work product or accomplish some project milestone have substantial benefit. But there’s something that’s even more important. Tools can provide new ways of looking at software engineering information—ways that improve the insight of the engineer doing the work. This leads to better decisions and higher software quality.

What are the steps? CASE is used in conjunction with the process model that is chosen. If a full tool set is available, CASE will be used during virtually every step of the software process.

What is the work product? CASE tools assist a software engineer in producing high-quality work products. In addition, the availability of automation allows the CASE user to produce additional customized work products that could not be easily or practically produced without tool support.

How do I ensure that I’ve done it right? Use tools to complement solid software engineering practices—not to replace them. Before tools can be used effectively, a software process framework must be established, software engineering concepts and methods must be learned, and software quality must be emphasized. Only then will CASE provide benefit.

A TAXONOMY OF CASE TOOLS

CASE tools can be classified by function

Business process engineering tools. By modeling the strategic information requirements of an organization, business process engineering tools provide a "meta-model" from which specific information systems are derived. Rather than focusing on the requirements of a specific application, business information is modeled as it moves between various organizational entities within a company. The primary objective for tools in this category is to represent business data objects, their relationships, and how these data objects flow between different business areas within a company.

Process modeling and management tools. If an organization works to improve a business (or software) process, it must first understand it. Process modeling tools (also called process technology tools) are used to represent the key elements of a process so that it can be better understood. Such tools can also provide links to process descriptions that help those involved in the process to understand the work tasks that are required to perform it. Process management tools provide links to other tools that provide support to defined process activities.

Project planning tools. Tools in this category focus on two primary areas: software project effort and cost estimation and project scheduling. Estimation tools compute estimated effort, project duration, and recommended number of people for a project. Project scheduling tools enable the manager to define all project tasks (the work breakdown structure), create a task network (usually using graphical input), represent task interdependencies, and model the amount of parallelism possible for the project.

Risk analysis tools. Identifying potential risks and developing a plan to mitigate, monitor, and manage them is of paramount importance in large projects. Risk analysis tools enable a project manager to build a risk table by providing detailed guidance in the identification and analysis of risks.

Project management tools. The project schedule and project plan must be tracked and monitored on a continuing basis. In addition, a manager should use tools to collect metrics that will ultimately provide an indication of software product quality. Tools in the category are often extensions to project planning tools.

Requirements tracing tools. When large systems are developed, things "fall into the cracks." That is, the delivered system does not fully meet customer specified requirements. The objective of requirements tracing tools is to provide a systematic approach to the isolation of requirements, beginning with the customer request for proposal or specification. The typical requirements tracing tool combines human interactive text evaluation with a database management system that stores and categorizes each system requirement that is "parsed" from the original RFP or specification.

Metrics and management tools. Software metrics improve a manager's ability to control and coordinate the software engineering process and a practitioner's ability to improve the quality of the software that is produced. Today's metrics or measurement tools focus on process and product characteristics. Management-oriented tools capture project specific metrics (e.g., LOC/person-month, defects per function point) that provide an overall indication of productivity or quality. Technically oriented tools determine technical metrics that provide greater insight into the quality of design or code.

Documentation tools. Document production and desktop publishing tools support nearly every aspect of software engineering and represent a substantial "leverage" opportunity for all software developers. Most software development organizations spend a substantial amount of time developing documents, and in many cases the documentation process itself is quite inefficient. It is not unusual for a software development organization to spend as much as 20 or 30 percent of all software development effort on documentation. For this reason, documentation tools provide an important opportunity to improve productivity.

System software tools. CASE is a workstation technology. Therefore, the CASE environment must accommodate high-quality network system software, object management services, distributed component support, electronic mail, bulletin boards, and other communication capabilities.

Quality assurance tools. The majority of CASE tools that claim to focus on quality assurance are actually metrics tools that audit source code to determine compliance with language standards.

Database management tools. Database management software serves as a foundation for the establishment of a CASE database (repository) that we have called the project database. Given the emphasis on configuration objects, database management tools for CASE are evolving from relational database management systems to object oriented database management systems.

Software configuration management tools. Software configuration management lies at the kernel of every CASE environment. Tools can assist in all five major SCM tasks—identification, version control, change control, auditing, and status accounting. The CASE database provides a mechanism for identifying each configuration item and relating it to other items; the change control process can be implemented with the aid of specialized tools; easy access to individual configuration items facilitates the auditing process; and CASE communication tools can greatly improve status accounting (reporting information about changes to all who need to know).

Analysis and design tools. Analysis and design tools enable a software engineer to create models of the system to be built. The models contain a representation of data, function, and behavior (at the analysis level) and characterizations of data, architectural, component-level, and interface design.1 By performing consistency and validity checking on the models, analysis and design tools provide a software engineer with some degree of insight into the analysis representation and help to eliminate errors before they propagate into the design, or worse, into implementation itself.

PRO/SIM tools. PRO/SIM (prototyping and simulation) tools provide the software engineer with the ability to predict the behaviour of a real-time system prior to the time that it is built. In addition, these tools enable the software engineer to develop mock-ups of the real-time system, allowing the customer to gain insight into the function, operation and response prior to actual implementation.

Interface design and development tools. Interface design and development tools are actually a tool kit of software components (classes) such as menus, buttons, window structures, icons, scrolling mechanisms, device drivers, and so forth. However, these tool kits are being replaced by interface prototyping tools that enable rapid onscreen creation of sophisticated user interfaces that conform to the interfacing standard that has been adopted for the software.

Prototyping tools. A variety of different prototyping tools can be used. Screen painters enable a software engineer to define screen layout rapidly for interactive applications. More sophisticated CASE prototyping tools enable the creation of a data design, coupled with both screen and report layouts. Many analysis and design tools have extensions that provide a prototyping option. PRO/SIM tools generate skeleton Ada and C source code for engineering (real-time) applications. Finally, a variety of fourth generation tools have prototyping features.

Programming tools. The programming tools category encompasses the compilers, editors, and debuggers that are available to support most conventional programming languages. In addition, object-oriented programming environments, fourth generation languages, graphical programming environments, application generators, and database query languages also reside within this category.

Web development tools. The activities associated with Web engineering are supported by a variety of tools for Web App development. These include tools that assist in the generation of text, graphics, forms, scripts, applets, and other elements of a Web page.

Integration and testing tools. In their directory of software testing tools, Software Quality Engineering [SQE95] defines the following testing tools categories:

·         Data acquisition—tools that acquire data to be used during testing.

·         Static measurement—tools that analyze source code without executing test cases.

·         Dynamic measurement—tools that analyze source code during execution.

·         Simulation—tools that simulate function of hardware or other externals.

·         Test management—tools that assist in the planning, development, and control of testing.

·         Cross-functional tools—tools that cross the bounds of the preceding categories.

It should be noted that many testing tools have features that span two or more of the

categories.

Static analysis tools. Static testing tools assist the software engineer in deriving test cases. Three different types of static testing tools are used in the industry: code based testing tools, specialized testing languages, and requirements-based testing tools.

·         Code-based testing tools accept source code (or PDL) as input and perform a number of analyses that result in the generation of test cases.

·         Specialized testing languages (e.g., ATLAS) enable a software engineer to write detailed test specifications that describe each test case and the logistics for its execution.

·         Requirements-based testing tools isolate specific user requirements and suggest test cases (or classes of tests) that will exercise the requirements.

Dynamic analysis tools. Dynamic testing tools interact with an executing program, checking path coverage, testing assertions about the value of specific variables, and otherwise instrumenting the execution flow of the program. Dynamic tools can be either intrusive or nonintrusive. An intrusive tool changes the software to be tested by inserting probes (extra instructions) that perform the activities just mentioned. Nonintrusive testing tools use a separate hardware processor that runs in parallel with the processor containing the program that is being tested.

Test management tools. Test management tools are used to control and coordinate software testing for each of the major testing steps. Tools in this category manage and coordinate regression testing, perform comparisons that ascertain differences between actual and expected output, and conduct batch testing of programs with interactive human/computer interfaces. In addition to the functions noted, many test management tools also serve as generic test drivers. A test driver reads one or more test cases from a testing file, formats the test data to conform to the needs of the software under test, and then invokes the software to be tested.

Client/server testing tools. The c/s environment demands on specialized testing tools that exercise the graphical user interface and the network communications requirements for client and server.