In this paper we discuss the use of an object-oriented approach for webbased applications design, based on a method named Object-Oriented Hypermedia Design Method (OOHDM). We first motivate our work discussing the problems encountered while designing large scale, dynamic web-based applications, which combine complex navigation patterns with sophisticated computational behavior. We argue that a method providing systematic guidance to design is needed. Next, we introduce OOHDM, describing its main activities, namely: conceptual design, navigational design, abstract interface design and implementation, and discuss how OOHDM designs can be implemented in the WWW. Finally, related work and future research in this area are further discussed.

In this paper we discuss the use of design patterns for the process of building hypermedia applications. The idea of design patterns has been recently developed, and rapidly spread outside the object-oriented community to a general audience of software developers. By using patterns it is not only possible to document design experience with a very simple and comprehensible format, but also reuse the same experience several times for different applications. We argue that the hypermedia community will take a vital step towards better designs of hypermedia applications and systems by developing a pattern language for that domain. KEYWORDS: Design Patterns, Pattern Languages, Hypermedia Design, Navigation, Interface 1 INTRODUCTION Hypermedia applications are usually built from scratch, which is not surprising given the relative youth of the hypermedia market. However, the key reason of why hypermedia components are not systematically reused is that current design approaches are n...

Patterns have shown to be an effective means of capturing and communicating software design experience. However, there is more to patterns than software design patterns: We believe that patterns work for software development on several levels. In this paper we explore what we have come to understand as crucial aspects of the pattern concept, relate patterns to the different models built during software design, discuss pattern forms and how we think that patterns can form larger wholes like pattern handbooks. 1 Introduction Design patterns have become a hotly discussed topic in software development. We and many other researchers have been using and experimenting with patterns over the last years. We have applied patterns and observed their usage within software development. We have used and seen several definitions of patterns, and we have experimented with pattern forms. The emerging literature shows a flourishing and fruitful diversity of pattern definitions, forms and applications. ...

Reuse is increasingly strategic for reducing cost and improving quality of hypermedia design and development. In this paper, based on the design and development of a real hypermedia application, we classify and explore different types of reuse in hypermedia design. We show how constructive templates constitute a practical technique for capturing the specification of reusable structures and components and enabling the automation of the production process. We also discuss connections between constructive templates and design patterns.

When designing a new application, experienced software engineers usually try to employ solutions that proved successful in previous projects. Such reuse of code organizations is seldom made explicit. Nevertheless it represents important information about the system, that can be extremely valuable in the maintenance phase, by documenting the design choices underlying the implementation. In addition, having it available, it can be reused whenever a similar problem is encountered. In this paper an approach is proposed to the inference of recurrent design patterns directly from the code or the design. No assumption is made on the availability of any pattern library, and the concept analysis algorithm, adapted for this purpose, is able to infer the presence of class groups which instantiate a common, repeated pattern. In fact, concept analysis provides sets of objects sharing attributes, which, in the case of object oriented design patterns, become class members or inter-class relations. The approach was applied to a C++ application, for which the structural relations among classes led to the extraction of a set of structural design patterns, which could be enriched with non structural information about class members and method invocations. The resulting patterns could be interpreted as meaningful organizations aimed at solving general problems which have several instances in the analyzed application.

There has been a recent increase in the number of published design patterns for hypermedia. Some of these patterns have been evolving, while others have remained untouched. This paper attempts to list all the patterns currently known, tracing the different publications in which they have appeared. The patterns are scrutinized and refined: some patterns are unified into one; some are deemed special cases of other patterns; some patterns are renamed. At the same time, we propose to rewrite the patterns in a vocabulary that is uniform, and to use similar pattern templates. We then discuss the creation of a design patterns system, which organizes the patterns and assists the designer in the process of recognizing the problems and their potential solutions. Finally, we propose a subset of the patterns which should conform a catalog of basic patterns; this catalog will attempt to address the most common problems found during the design of hypermedia applications. Keywords: hypermedia design...

A parallel program archetype is an abstraction that captures the common features of a class of problems with similar computational structure and combines them with a parallelization strategy to produce a pattern of dataflow and communication. Such abstractions are useful in application development, both as a conceptual framework and as a basis for tools and techniques. This paper describes an approach to parallel application development based on archetypes and presents two example archetypes with applications. 1 Introduction This paper proposes a specific method of exploiting computational and dataflow patterns to help in developing reliable parallel programs. A great deal of work has been done on methods of exploiting design patterns in program development. This paper restricts attention to one kind of pattern that is relevant in parallel programming: the pattern of the parallel computation and communication structure. Methods of exploiting design patterns in program develop...

Global networking has brought with it both new opportunities and new security threats on a worldwide scale. Since the Internet is inherently insecure, secure cryptographic protocols and a public key infrastructure are needed. In this paper we introduce a protocol component architecture that is well suited for the implementation of telecommunications protocols in general and cryptographic protocols in particular. Our implementation framework is based on the Java programming language and the Conduits+ protocol framework. It complies with the Beans architecture and security API of JDK 1.1, allowing its users to implement application specific secure protocols with relative ease. Furthermore, these protocols can be safely downloaded through the Internet and run on virtually any workstation equipped with a Java capable browser * . The framework has been implemented and tested in practice with a variety of cryptographic protocols. The framework is relatively independent of the actual crypto...

ABSTRACT: Object-oriented frameworks have extended reusability of software from code modules to architectural and domain information. This paper further extends software reusability from code and architecture to built-in tests (BITs) in object-oriented framework development. Methods for embedding BITs at object and object-oriented framework levels are addressed. Behaviours of objects and object-oriented frameworks with BITs in the normal and test modes are analyzed. Systematic reuse methods of BITs in object-oriented framework development are provided. The most interesting development in the paper is that the BITs in object-oriented frameworks can be inherited and reused as that of code. Therefore testability and maintainability of the test-built-in object-oriented frameworks can be improved by the BIT approach. The BIT method can be used in analysis, design and coding of object-oriented frameworks.

Object-oriented (OO) design patterns define collections of interconnected classes that serve a particular purpose. A design pattern is a structural unit in a system built out of patterns, not unlike the way a function is a structural unit in a procedural program or a class is a structural unit in an OO system designed without patterns. When designers treat patterns as structural units, they become concerned with issues such as coupling and cohesion at a new level of abstraction. We examine the notion of pattern coupling to classify how designs may include coupled patterns. We find many examples of coupled patterns; this coupling may be "tight" or "loose", and provides both benefits and costs. We qualitatively assess the goodness of pattern coupling in terms of effects on maintainability, factorability, and reusability when patterns are coupled in various ways. Keywords: Design patterns, object-oriented design, design quality, coupling. 1.