Understanding the implementation of a certain feature of a system requires to identify the computational units of the system that contribute to this feature. In many cases, the mapping of features to the source code is poorly documented. In this paper, we present a semi-automatic technique that reconstructs the mapping for features that are triggered by the user and exhibit an observable behavior. The mapping is in general not injective; that is, a computational unit may contribute to several features. Our technique allows to distinguish between general and specific computational units with respect to a given set of features. For a set of features, it also identifies jointly and distinctly required computational units.

As a complex software system evolves, its implementation tends to diverge from the intended or documented design models. Such undesirable deviation makes the system hard to understand, modify, and maintain. This paper presents a hybrid computer-assisted approach for confirming that the implementation of a system maintains its expected design models and rules. Our approach closely integrates logicbased static analysis and dynamic visualization, providing multiple code views and perspectives. We show that the hybrid technique helps determine design-implementation congruence at various levels of abstraction: concrete rules like coding guidelines, architectural models like design patterns[7] or connectors[26], and subjective design principles like low coupling and high cohesion. The utility of our approach has been demonstrated in the development of mChoices, a new multimedia operating system which inherits many design decisions and guidelines learned from experience in the construction and maintenance of its predecessor, Choices

Dynamic information collected as a software system executes can help software engineers perform some tasks on a system more effectively. To interpret the sizable amount of data generated from a system's execution, engineers require tool support. We have developed an off-line, flexible approach for visualizing the operation of an object-oriented system at the architectural level. This approach complements and extends existing profiling and visualization approaches available to engineers attempting to utilize dynamic information. In this paper, we describe the technique and discuss preliminary qualitative studies into its usefulness and usability. These studies were undertaken in the context of performance tuning tasks. Keywords Software visualization, programming environments, software structure, program comprehension, execution trace, performance. 1 INTRODUCTION Effective performance of many software engineering tasks requires knowledge of how the system works. Gaining the desired k...

Implementing, validating, modifying, or reengineering an object-oriented system requires an understanding of the object and class interactions which occur as a program executes. This work seeks to identify, visualize, and analyze interactions in object-oriented program executions as a means for examining and understanding dynamic behavior. We have discovered recurring interaction scenarios in program executions that can be used as abstractions in the understanding process, and have developed a means for identifying these interaction patterns. Our visualizations focus on supporting design recovery, validation, and reengineering tasks, and can be applied to both object-oriented and procedural programs.

Execution patterns are a new metaphor for visualizing execution traces of object-oriented programs. We present an execution pattern view that lets a programmer visualize and explore a program's execution at varied levels of abstraction. The view employs visual, navigational, and analytical techniques that accommodate lengthy, real-world traces. By classifying repetitive behavior automatically into high-order execution patterns, we drastically reduce the information a programmer must assimilate, with little loss of insight.

The reengineering and reverse engineering of software systems is gaining importance in software industry, because the accelerated turnover in software companies creates legacy systems in a shorter period of time. Especially understanding classes is a key activity in object-oriented programming, since classes represent the primary abstractions from which applications are built. The main problem of this task is to quickly grasp the purpose of a class and its inner structure. To help the reverse engineers in their first contact with a foreign system, we propose a categorization of classes based on the visualization of their internal structure. The contributions of this paper are a novel categorization of classes and a visualization of the classes which we call the class blueprint. We have validated the categorization on several case studies, two of which we present here. Keywords Reverse Engineering, Program Understanding, Software Visualization, Visual Patterns, Smalltalk 1.

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This paper describes a way of organizing information aboutan object-oriented program's execution. The context is our system for visualizing that execution. The critical constraints are completeness, compactness, and efficient retrieval. We describe our design and how it meets these constraints. 1 Introduction Much is known about how to characterize programs statically. Contemporary programming languages embody countless lessons learned over nearly a half century of modern computing. It's clear that a language must balance expressiveness and simplicity, abstraction and specificity, flexibility and robustness. The proportions can vary according to need, but programming language design is necessarily a compromise between conflicting goals. We can think of a programming language as defining a vast space of legal programs relatively few of which are of any practical use. To define a space we must have orthogonal dimensions. In the case of structured programming languages we might devote on...

Reverse engineering software systems has become a major concern in software industry because of their sheer size and complexity. This problem needs to be tackled, since the systems in question are of considerable worth to their owners and maintainers. In this article we present the concept of a polymetric view, a lightweight software visualization technique enriched with software metrics information. Polymetric views help to understand the structure and detect problems of a software system in the initial phases of a reverse engineering process. We discuss the benefits and limits of several predefined polymetric views we have implemented in our tool CodeCrawler. Moreover, based on clusters of different polymetric views we have developed a methodology which supports and guides a software engineer in the first phases of a reverse engineering of a large software system. We have refined this methodology by repeatedly applying it on industrial systems, and illustrate it by applying a selection of polymetric views to a case study.

To fully understand the underlying architecture of an object-oriented software system, both static and dynamic analyses are needed. Dynamic reverse engineering techniques are especially important for understanding the run-time behavior of objects in a distributed object systems and in systems that rely heavily on polymorphism. Shimba, a prototype reverse engineering environment, has been built to support understanding an existing Java software system. The dynamic event trace information is generated automatically as a result of running the target system under a customized sdk [14] debugger and viewed as scenario diagrams using the SCED tool [5]. In SCED, state diagrams can be synthesized automatically from scenario diagrams. This facility is used to visualize the total behavior of a selected object or method, disconnected from the rest of the system. This paper demonstrates how Shimba aids understanding the behavior of Java programs. A case study in made to validate the usefulness of ...