IdAlreadyInUseException While Using BarabasiAlbertGenerator

["Jacob M. H. Smith" <jacob.m.h.smith AT gmail.com>]

Hello.

I'm using GraphStream 1.2 and I'm having the following problem.

I use the BarabasiAlbertGenerator to populate my graph like this:

/* ============================================== */
Generator generator = new BarabasiAlbertGenerator();
generator.addSink(graph);
generator.begin();
for (int i = 0; i < 100; i++) {
    generator.nextEvents();
}
generator.end();
/* ============================================== */

Later in my program I call the graph's clear() method and do the same thing 
again. The second time I get an IdAlreadyInUseException.

What am I doing wrong? Am I using the generator or the graph in a way that 
wasn't intended?

Best regards,
Jacob