This lib is needed by argouml but can be used within different applications.

the goal of the gef project is to build a graph editing library that can be used to construct many, high-quality graph editing appications. some of gef's features are:
* a simple, concrete design that makes the framework easy to understand and
extend.
* node-port-edge graph model that is powerful enough for the vast majority
of connected graph applications.
* model-view-controller design based on the swing java ui library makes gef
able to act as a ui to existing data structures, and also minimizing learning
time for developers familiar with swing.
* high-quality user interactions for moving, resizeing, reshaping, etc. gef
also supports several novel interactions such as the broom alignment tool
and secltion-action-buttons.
* generic properties sheet based on javabeans introspection.
* xml-based file formats based on the pgml standard (soon to support svg).