SKilL graph visualization and manipulation

Abstract

The serialisation system SKilL stores mutually referenced objects in a binary file format. Thus, a special programme is required to view the serialised data or perform ad hoc modification. This thesis discusses the implementation of such an editor in the programming language Scala. After giving a sketch of the SKilL system, the main part of this thesis is concerned with the visualisation of the data. Due to references, the contents of an object can usually not be understood in isolation but only in combination with the objects which it references. The objects and their mutual references are, therefore, visualised as a node-link diagram of the neighbourhood of a given object. For the layout of the diagram, existing force directed placement algorithms are reviewed and solutions from different sources are combined. In order to produce comprehensible layouts, an additional constraint, which aligns all links that represent the same field in the underlying data, is added to the placement algorithm. The implementation works reasonably well with small graphs, but the quality of the layout deteriorates for larger or highly connected graphs. The remainder covers the modification, creation, and deletion of objects. No satisfying solution was found for nested maps. Finally, a simple search function is sketched.