Scalable Visualizations of Object-Oriented Systems with Ownership Trees

Abstract

Executing object-oriented programs have a complex structure consisting of numerous objects connected by interobject references. This structure, called the program's object graph, is hard to understand, and this complicates learning, teaching, debugging and maintaining object-oriented programs. While visualization can be used to display object graphs, the size and complexity of typical object graphs also makes visualization difficult. We have developed ownership trees as a simple yet powerful method of extracting a program's implicit encapsulation structure from its object graph. We have developed a program visualization tool that makes use of ownership trees to display the structure of object-oriented programs. Because ownership trees are independent of scale—the relationship between a whole object-oriented system and its top-level components is the same as the relationship between a low-level data structure and the objects that implement it—our software visualization is applicable at all levels of abstraction within a program's design.