Understanding Object-Oriented Programs with Declarative Event Analysis

Understanding how components in an application interact to ensure a certain functionality is an essential aspect of understanding a software application. To obtain this kind of information an analysis of the dynamic behavior of an application is more appropriate than a static analysis of the code. Understanding dynamic behavior through event analysis is a challenge because of the large amount of data gathered through program executions. In this paper, we show how we define declarative queries that allow us to filter the event data collected and to define new abstractions which aid in program understanding. 1 Program Understanding through Queries and Views Program understanding is an important aspect of software engineering. It is essential in the maintainance and reengineering of a system, and especially critical for extending and using frameworks. While documentation should address the program understanding problem, it is often not up-to-date, or missing altogether, and in general does not cover all aspects of an application and as such may not at all address the particular aspect an engineer is interested in. The best remedy for this lack of appropriate documentation is to allow an engineer to extract documentation from the application for the particular aspect of interest. We believe that a good tool for program understanding should allow an engineer to formulate hypotheses about the structure of the software, and to confirm or reject hypotheses based on evidence from the source code. One such tool is described by Murphy in [MN97]. It allows an engineer to define a high-level model of the software system and a mapping of the source-code onto this model. A ’reflexion model’ is then computed which shows how close the high-level model comes to describing the source code. This allows the engineer to iteratively refine the high-level model, so that it better reflects the implementation. This is a promising approach: an engineer can choose what to query depending on his strategy for understanding the code and on the aspect he is particularly interested in. Each query about an hypothesis gives a view of the software system, and different views can also be combined to get a better understanding of the software [YHC97]. Institut für Informatik (IAM), Universität Bern, Neubrückstrasse 10, 3012 Berne, Switzerland (richner,ducasse)@iam.unibe.ch, http://www.iam.unibe.ch/ (richner,ducasse)/ yPleinlaan 2, 1050 Brussels, Belgium [email protected], http://progwww.vub.ac.be/ rwuyts/