Myth and Reality of OOA: the lack of domain knowledge in the representation

Myth and Reality of OOA:the lack of domain knowledge in the representation Matti Sadeh Roi Gelbard Dov Te’eni

informatics Computer Science IS ACM – IEEE MIS Quarterly ISR Management Science ) HCI (International Journal of Human computer studies Myth and Reality of OOA

1. Facts about practice of OOA • Object-Orientation is the most widely discussed Systems Development approach. • Books, Researches, Papers, Interest groups… • What happens in practice? 2. Speculation In practice, no inclusion of relevant theories Myth and Reality of OOA

The OO Promise Many see the OO approach as a panacea to software problems: “It is a major premise of this book that the object-oriented approach to systems development helps to avoid many of the problems and pitfalls described in earlier chapters" [of the structured or functional analysis] (Bennett, McRobb and Farmer, 2002) However, little empirical evidence exist to support such premise, and most of them are lab results. Myth and Reality of OOA

The Current Research • The current research tests empirically the application of the OO approach, with special emphasis on analysis. Myth and Reality of OOA

The promise of OOA The OO approach holds the promise to cope with the traditional waterfall life cycle pitfalls: • Real world projects don’t follow a simple sequential life-cycle. • Inadequacies in the requirements analysis will arise in the late stages of the project • A long time may elapse between the initial system requirements stage and final installation. • The traditional life-cycle tends to be unresponsive to changes in client requirements or technology. • The transition between stages is not smooth - in OO smooth. • OO designs are more suited to real world problems • The OO software will be easier to understand • Better support for software reuse Myth and Reality of OOA

OOA Principles Since the late ’80 many OO methodologies where suggested, but one can treat the work of the OMG (2001) as a conclusive work. The essentials of OO are: • Seeing the system as a collection of object that interact. • Classification of the objects into classes • Generalizations of classes to super-classes • Inheritance • Encapsulation • Polymorphism • Use of visual language (diagrams) • Continuance evolving approach to system life-cycle Myth and Reality of OOA

Sample characteristics Myth and Reality of OOA

Research method - Interviews • Diversity between projects suggested interviews best. • Project differ by: LC models, language, deliverables and more. • To manage risks (researcher bias, social desire) of such research few steps where adopted: • Structured interviews – skeletons, questions phrased up-front • Assuring the interviewees confidentiality • Gradual questions from ‘what’ through ‘How’ to ‘Why’ – postponing judgment questions to the end • Clear translation map from interview to quantitative measures Myth and Reality of OOA

The generic life-cycle Although much is discussed about the iterative LC and its benefits the practice follows a more structured LC Customer Requirements RFP, SOW, MRD, or other. Might be divided into Sys. Req and SRS Software Requirements Software Analysis Software Design May be divided HLD & LLD Myth and Reality of OOA

Findings – Activities in stages Analysis and design activities are pushed down the LC Myth and Reality of OOA

Findings – Requirements specification • Requirements state the functionality needed from the system (not the objects that it will handle) • Requirements are broken-down by their functionality. Myth and Reality of OOA

Findings – Analysis • In small projects and in some cases of information system development - might be neglected, jumping straight to implementation (overhead?) • In most cases – functions allocated to components. • Most times – not yet dealing with objects • When classes identified, almost never use the OO power of inheritance. • Declair interfaces within the system (between components) and with external systems. • Most times – UI design (specifically) Myth and Reality of OOA

Findings – Design • Hardly ever full specification of system – the gap between the specification and the S/W system relate to • the complexity of the system, • knowledge and experience of the programmer, • usage of CASE tools • customer demands • Not all the classes are designed or even identified • Complex methods tend to be more specified Might suggest cost-effectiveness of design not fully proven. Myth and Reality of OOA

Findings – Design • In most cases the design model is not kept updated. • implies about the usefulness of the model for maintenance Myth and Reality of OOA

Findings - Graphical Language Myth and Reality of OOA

Findings - Graphical Language • The graphical language is not fully adopted • Usually, text complements diagrams • Nevertheless, diagrams deliver quickly the overall picture • Two exceptions: • one very large project – design is completely graphical. Text is not feasible in such huge system. • Another, medium-scale project – completely textual descriptions of process (diagrams are overhead) Myth and Reality of OOA

Story II (a little speculative):we do not in practice, include theory Myth and Reality of OOA

(Systems modeling, 2000) Myth and Reality of OOA

Type of information – theory implications? Myth and Reality of OOA

Myth and Reality of OOA

An example of theory A cognitive-affective model of organizational communication:theory informs design MIS Quarterly, 2001 Myth and Reality of OOA

Design Principles of Communication support systems(forthcoming Communications ACM) • Principle 1: Design must simultaneously consider enhancing mutual understanding and promoting relationships between communicators • Principle 2: Design should support adaptive behavior, including the contingent use of alternative communication strategies, alternative message forms and alternative media. • Principle 3: Design should control complexity. Myth and Reality of OOA

Design Principles of Communication support systems (Cont.) • Principle 4: Design should support multiple levels of communication and easy travel between levels. • Principle 5: Memory should consist of speech act components, situations, norms and values. • Principle 6: Memory should consist of associative information, accessible through multiple media, and represented in multiple forms, allowing for indeterminate and emergent views too Myth and Reality of OOA

Original message IEEE Trans. Intelligent systems 2000 w Schwartz Myth and Reality of OOA

Contextualized message Myth and Reality of OOA

Myth and Reality of OOA: the lack of domain knowledge in the representation