The object-oriented programming language design space consists of class-based and prototype-based languages. Both language families have been shown to posses many advantages but also several disadvantages with respect to software construction. Hybrid languages featuring both prototype-based and class-based mechanisms have been proposed as a solution. Unfortunately these languages not only unify the advantages but also the disadvantages of both families. In this paper we propose a more intersectional point of view and propose a language that inherits the advantages but shuns the disadvantages of both families.

n of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation. Categories and Subject Descriptors: I.6.5 [Simulation Modeling]: Model Developmentmodeling methodologies; I.6.8 [Simulation Modeling]: Types of Simulationdistributed General Terms: Design Additional Key Words and Phrases: Web-based simulation, aircraft design, Java, object-oriented 1. INTRODUCTION Intensive competition in the commercial aviation industry is placing increasing pressure on aircraft manufacturers to reduce the time, cost and risk of product development. To compete effectively in today's global marketplace, innovative approaches to reducing

As the CORBA Component specification has been adopted by the OMG, it is now necessary to provide CORBA Component platforms in order to offer environment to build component-based distributed applications. This article presents one possible approach to build such a platform. This approach intends to provide a dynamic platform that would allow the incremental building of distributed applications using a prototype-based way. Presenting an overview of the CCM, this article focuses on the key elements of the CCM for a dynamic use. The four elements of our platform are then discussed: an IDL3/CIDL preprocessor, generic container servers, the graphical console, and a deployment tool. As we are currently working on the implementation of this platform, performed tasks and intended tasks are presented. 1. Introduction The CORBA Component specification [2] has been adopted during the San Jose meeting (August 1999) of the Object Management Group. From this stage, the next step is to build CORBA C...

This paper describes a new approach towards code reuse through a high-level programming language. This work has been developed in the context of combinatorial optimization for industrial problems, where performance is critical and where a large number of fairly complex algorithms are used, that often share similar structures (such as branch & bound). The result is the CLAIRE programming language, which provides high levels of abstraction and parametrization. Consequently, it may be used as an executable pseudo-code to describe concise and reusable problem solving algorithms.

We describe participatory programming as a process that spans design, programming, use and tailoring of software. This process, that includes end-users at each stage, integrates participatory design and programmability. Programmability, as a property that relies on a reflective architecture, aims to let the end-users evolve the tools themselves according to their current, specific needs and to let them control better the way results are computed. We present an environment that results from this approach, called biok, developed for researchers in biology, which is both domain-oriented and open to full programming.

Window Toolkit (AWT) [28]. The AWT is an integral part of the Java run-time system and provides a collection of platform-independent components for building graphical applications using Java. The AWT offers support for drawing and image operations, as well as supplying common graphical user-interface objects such as Buttons, Lists, TextFields, Choice boxes, etc. Platform independence is achieved through the use of peers which are native GUI components manipulated by the AWT. Peers allow Java programs that use the AWT to retain the familiar look and feel of the host computer's native windowing system. Consequently, when a Java program is run on a Macintosh computer, the Buttons, Windows, List boxes, etc., all appear in the familiar Macintosh style. When the same program is run on a computer running Windows NT^TM, those same windowing components will appear as Window NT-style objects. The figures in this paper illustrate this concept. The Java Gas Turbine Simulator was run on several dif...

The need for comparison between AOP and related approaches has been retained as a key issue in [MLTK97]. We have noticed strong similarities between AOP and some object-oriented approaches including some notion of viewpoint. We report them in this paper and we discuss how this brief comparison may be used for further discussion of the other key issues that were retained in [MLTK97].

Traits are reusable building blocks that can be explicitly composed to share methods across unrelated class hierarchies. In their original form, traits do not contain state and cannot express visibility control for methods. Two extensions, stateful traits and freezable traits, have been proposed to overcome these limitations. However, these extensions introduce complexity and have not yet been combined to add both state and visibility control to traits at the same time. This paper revisits the problem of adding state and visibility control to traits. Rather than extending the original traits model with additional operations, we use a fundamentally different approach by allowing traits to be lexically nested within other modules. This enables traits to express (shared) state and visibility control by hiding variables or methods in their lexical scope. Although the Traits’ “flattening property ” no longer holds when traits can be lexically nested, the combination of traits with lexical nesting results in a simple and more expressive trait model. We formally specify the operational semantics of this combination. Lexically nested traits are fully implemented in AmbientTalk, where they are used among others in the development of a Morphic-like UI framework.

Abstract. The majority of object migration systems do not support heterogeneous environments. Few systems solve this challenge by specifying a platform and language independent state transfer format, requiring a compatible implementation for every target language. However, fields of research like Ubiquitous and Pervasive Computing with mobile users and applications demand an even more platform-independent, flexible and adaptive approach. This paper presents a novel approach for adaptive object and agent migration in heterogeneous environments based on our former work enabling language- and platform-independent object mobility in CORBA. By providing flexible mechanisms to reduce, expand and transform an object’s state and functionality during migration, we support adaptation to the context and application-specific demands at the target system. This is achieved by introducing a separation of state, functionality and implementation code instead of mapping particular state on particular code. Our prototype system supports object migration from Java to C++ and vice versa. In principle, our concept can be transferred to any CORBA-supported programming language.

This paper introduces class composition as a more productive approach towards hot spots, offering all of the advantages of both class inheritance and object composition but involving extra work for the framework designer. c fl 1998 John Wiley & Sons