Although the Java programming language has achieved widespread acceptance, one feature that seems sorely missed is the ability to use type parameters (as in Ada generics, C++ templates, and ML polymorphic functions or data types) to allow a general concept to be instantiated to one or more specific types. In this paper, we propose parameterized classes and interfaces in which the type parameter may be constrained to either implement a given interface or extend a given class. This design allows the body of a parameterized class to refer to methods on objects of the parameter type, without introducing any new type relations into the language. We show that these Java extensions may be implemented by expanding parameterized classes at class load time, without any extension or modification to existing Java bytecode, verifier or bytecode interpreter. 1 Introduction In Ada generics [US 80], C++ templates [ES90], and ML polymorphic functions and data types [Mil85, Ull94], type parameterizati...

Abstract The trends in software development are towards larger programs, more complex programs, and more use of programs as "component software. " These trends mean that the features of modern programming languages are becoming more important than ever before. Programming languages need to have features such as strong typing, a module system, polymorphism, automatic storage management, and higher-order functions. In short, modern programming languages are becoming more important than ever before.

All engineering disciplines rely on standard components to design and build artifacts. The key technical challenge in software engineering is to enable the adoption of such a model to the development of software. The transformationfrom line-by-line development to component-based development will address many of the industry’s productivity and quality problems. Indeed, component-based software development has been a long- standing dream of the software industry, prompting a search for both technical and nontechnical solutions. A successful approach to component- based development requires a comprehensive solution that draws on advances in programming languages, programming paradigms, algorithm analysis, and software design. The technical problem can only be addressed by such an integrated solution. This paper presents an approach based on the C++ Standard Template Library. More than a traditional library, STL embodies a concrete approach to software design based on a well-defined taxonomy and theory of software components. I present the fundamental contributions of STL to a paradigm of component programming-a component-based software development paradigm in which there is a clear separation between component development and application development. I motivate component programming, give the requirements for components and catalogs, and give an example of component programming applied to the standard Keyword in Context (KWIC) problem. I then summarize the implications of component programming for the software industry and for software engineering education.

Many language theoreticians have taken great efforts in designing higher-level programming languages that are more elegant and more expressive than conventional languages. However, few of these new languages have been implemented very efficiently. The result is that most software engineers still prefer to use conventional languages, even though the new higherlevel languages offer a better and simpler programming model. This dissertation concentrates on improving the performance of programs written in Standard ML (SML)---a statically typed functional language---on today's RISC machines. SML poses tough challenges to efficient implementations: very frequent function calls, polymorphic types, recursive data structures, higher-order functions, and first-class continuations. This dissertation presents the design and evaluation of several new compilation techniques that meet these challenges by taking advantage of some of the higher-level language features in SML. Type-directed compilation ...

The typical implementations for parametric polymorphism in object oriented programming languages are space consuming, in that new binary code is created as new instantiations of parametric types are used. Recently, it was proposed a translation for parameterized types into Java, called LM translation, which avoids this problem by collecting type descriptors for parametric types at load-time. Another useful feature related to parametric polymorphism is that of parametric methods, which is often a necessary tool to completely benefit from th expressiveness and the code reuse of parametric polymorphism. In this paper the LM translator is extended in order to deal with parametric methods too. While previous implementations lead to a relevant size overhead, the one here proposed defers most of the overhead at the classes' load-time, with only little overhead at run-time. It turns out that the general impact of this implementation on the code execution is definitely lower than that of previous approaches. 1.

. The idea of making synchronous operations into first-class values is an important one for supporting abstraction and modularity in concurrent programs. This design principle has been used with great success in the concurrent language CML, but what are the limitations of this approach? This paper explains the rationale for first-class synchronous operations, and discusses their use in CML. It also presents some recent and fundamental results about the expressiveness of rendezvous primitives, which define the limitations of synchronous abstractions. 1 Introduction Abstraction is a key tool for managing complexity. The design of programming languages is one area where application of this idea has paid significant dividends. Languages have evolved from providing a fixed set of abstractions of the underlying hardware, such as arithmetic expressions and arrays, to providing support for programmer-defined abstractions, such as abstract data-types and higher-order procedures. By providing ...

this document therefore, is to give a brief survey of the important facilities available in Hol98; we will give only the `big picture', along with some hints for deeper exploration. The reader who completes the document should have an idea of how to formalize and prove simple things in Hol98, as well as an idea of how to go about extending the system to his or her own purposes.

Functional programming presents new challenges in the design of programming environments. In a strongly typed functional language, such as ML, much conventional debugging of runtime errors is replaced by dealing with compile time error reports. On the other hand, the cleanness of functional programming opens up new possibilities for incorporating sophisticated correctness-checking techniques into such environments. C Y NTHIA is a novel editor for ML that both addresses the challenges and explores the possibilities. It uses an underlying proof system as a framework for automatically checking for semantic errors such as non-termination. In addition, C Y NTHIA embodies the idea of programming by analogy --- whereby users write programs by applying abstract transformations to existing programs. This paper investigates C Y NTHIA's potential as a novice ML programming environment. We report on two studies in which it was found that students using C Y NTHIA commit fewer er...

The Wireless Transaction Protocol (WTP) is part of the Wireless Application Protocol (WAP) architecture and provides a reliable request-response service. The state space method of Coloured Petri Nets has been used to analyse a revised version of WTP, to gain a high level of confidence in the correctness of the design. Full state space analysis allows us to prove properties of the protocol for maximum values of the retransmission counters used in GSM networks (values are 4). However, the size of the state space grows rapidly as the maximum counter values are increased. We apply the sweep-line method to take advantage of the progress present in the protocol, notably the progression through major states of the protocol entities, and the increasing nature of the retransmission counters. The sweep-line method allows us to prove properties of the protocol for larger counter values, including those used in Internet Protocol (IP) networks (where the maximum values are 8). As a result, verification of WTP can be performed for the two most important networks (GSM and IP), the ones for which the WAP standard gives recommended maximum values for the retransmission counters.

Abstract In this work we introduce an automatic adaptation approach for Coloured Petri Nets models. For this approach we define a procedure for the synthesis of a new model based on a given model and a set of behavior restrictions. This procedure was defined based on the concepts and techniques of the supervisory control theory and model checking. Moreover, we tackle the adaptation problem in the context of models reuse.