This paper proposes that the distinguishing characteristic of Aspect-Oriented Programming (AOP) systems is that they allow programming by making quantified programmatic assertions over programs written by programmers oblivious to such assertions. Thus, AOP systems can be analyzed with respect to three critical dimensions: the kinds of quantifications allowed, the nature of the actions that can be asserted, and the mechanism for combining base-level actions with asserted actions. Consequences of this perspective are the recognition that certain systems are not AOP and that some mechanisms are expressive enough to allow programming an AOP system within them. A corollary is that while AOP can be applied to Object-Oriented Programming, it is an independent concept applicable to other programming styles. 1. Introduction This paper is about Aspect-Oriented Programming (AOP) qua programming language. We are interested in determining what makes a language AOP. This work was prompted by a que...

This paper presents an overview of the Cedar programming environment, focusing on its overall structure-that is, the major components of Cedar and the way they are organized. Cedar supports the development of programs written in a single programming language, also called Cedar. Its primary purpose is to increase the productivity of programmers whose activities include experimental pro-gramming and the development of prototype software systems for a high-performance personal computer. The paper emphasizes the extent to which the Cedar language, with run-time support, has influenced the organization, flexibility, usefulness, and stability of the Cedar environment. It high-lights the novel system features of Cedar, including automatic storage management of dynamically allocated typed values, a run-time type system that provides run-time access to Cedar data type definitions and allows interpretive manipulation of typed values, and a powerful deuice-independent imaging model that supports the user interface facilities. Using these discussions to set the context, the paper addresses the language and system features and the methodologies used to facilitate the integration of Cedar applications. A comparison of Cedar with other programming environments further identifies areas where Cedar excels and areas where work remains to be done.

Even when working on a well-modularized software system, programmers tend to spend more time navigating the code than working with it. This phenomenon arises because it is impossible to modularize the code for all tasks that occur over the lifetime of a system. We describe the use of a degree-of-interest (DOI) model to capture the task context of program elements scattered across a code base. The Mylar tool that we built encodes the DOI of program elements by monitoring the programmer’s activity, and displays the encoded DOI model in views of Java and AspectJ programs. We also present the results of a preliminary diary study in which professional programmers used Mylar for their daily work on enterprise-scale Java systems.

The monitoring of distributed systems involves the collection, interpretation, and display of infor-mation concerning the interactions among concurrently executing processes. This information and its display can support the debugging, testing, performance evaluation, and dynamic documentation of distributed systems. General problems associated with monitoring are outlined in this paper, and the architecture of a general purpose, extensible, distributed monitoring system is presented. Three approaches to the display of process interactions are described: textual traces, animated graphical traces, and a combination of aspects of the textual and graphical approaches. The roles that each of these approaches fulfill in monitoring and debugging distributed systems are identified and compared. Monitoring tools for collecting communication statistics, detecting deadlock, controlling the non-deterministic execution of distributed systems, and for using protocol specifications in monitoring are also described. Our discussion is based on experience in the development and use of a monitoring system within a distributed programming environment called Jade. Jade was developed within the Computer Science

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We present a formulation of interconnection models and present the unit and syntactic models --- the primary models used for managing the evolution of large software systems. We discuss various tools that use these models and evaluate how well these models support the management of system evolution. We then introduce the semantic interconnection model. The semantic interconnection model incorporates the advantages of the unit and syntactic interconnection models and provides extremely useful extensions to them. By refining the grain of interconnections to the level of semantics (that is, to the predicates that define aspects of behavior) we provide tools that are better suited to manage the details of evolution in software systems and that provide a better understanding of the implications of changes. We do this by using the semantic interconnection model to formalize the semantics of program construction, the semantics of changes, and the semantics of version equivalence and compatibi...

or Judith E. Grass Yih-Farn Chen AT&T Bell Laboratories Murray Hill, NJ 07974 The C++ Information Abstractor, cia++, builds a database of information extracted from C++ programs. The database can serve as a foundation for the rapid development of C++ programming tools. Such tools include tools that graphically display various views of the program structure, tools that answer queries about program symbols and relationships, and tools that extract self-contained components from a large system. Cia++ is a new abstractor implementation based on the design of the C Information Abstractor. This paper describes the conceptual model of cia++ and examples of relational views and applications developed on the C++ program database. It also presents some aspects of the implementation. 1 Motivation C++ is rapidly becoming a language of choice for developing large application programs due to its object-oriented paradigm. Many new C++ programmers come from the C programming community. The transit...

We present a general model of software development environments that consists of three components: structures, mechanisms and policies. The advantage of this model is that it distinguishes intuitively those aspects of an environment that are useful in comparing and contrasting software development environments. Our initial application of the model is to characterize four classes of environments by means of a sociological metaphor based on scale: the individual, the family, the city and the state models. The utility of the IFCS taxonomy is that it delineates the important classes of interactions among software developers and exposes the ways in which current software development environments inadequately support the development of large systems. We demonstrate the generality of our model by also applying it to a previously published taxonomy that categorizes environments according to how they relate to four historical trends: language-centered, structure-oriented, toolkit and method-bas...

In this paper, we explain how inheritance and dynamic binding make object-oriented programs difficult to maintain, and we give a concrete example of the problems that arise. We show that the difficulty lies in the fact that conventional tools are poorly suited for work with object-oriented languages, and we argue that semantics-based tools are essential for effective maintenance of object-oriented programs. We then describe a system we have developed for working with C++ programs. This system comprises a relational database system for information about programs, and an interactive database interface integrated with a text editor. We describe our system architecture, detail the database relations, provide informal evidence on the system's effectiveness, and compare it to other research with similar goals. Keywords: software maintenance, object-oriented languages and environments, programming environments, semantic analysis of code, software representation in relational databases, C++. ...

Types of code changes in an object oriented library are described. A formal model for capturing and inferencing on the changes to identify affected classes is described. The model consists of three types of diagrams: the object relation diagram (ORD), the block branch diagram (BBD), and the object state diagram (OSD). An ORD describes the inheritance, aggregation, and association relationships between the classes of a C++ library. A BBD describes the control structure and interfaces of a member function. And an OSD describes the state behavior of a class. Unlike in modeling, these diagrams are automatically generated from code and facilitate understanding and changing a C++ library. An OO software maintenance environment that implements the research result is described. Our experience with the environment prototype shows promising results.