[jgrapht-users] Documentation, implementation or me?

[Jonathan C. <jon...@it...>]

I am a huge fan of jgrapht. However, I have come across a problem with it. My understanding is that that the code below should work, but it doesn't. I have not dug into the source, but I can imagine that there is a hashcode issue, as it no longer seem to find the vertex that is there.

I am not sure if I have read the docs wrong, programmed wrong, or if this is simply a bug. The latter seems unlikely though, since it is such a core feature that this type of problem should have been caught long ago.

Thanks in advance for any help!

/Jonathan

import java.util.LinkedHashSet;
import java.util.Set;

import org.jgrapht.graph.DefaultEdge;
import org.jgrapht.graph.SimpleGraph;

public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {

		SimpleGraph<Set<String>, DefaultEdge> sg =
			new SimpleGraph<Set<String>, DefaultEdge>(DefaultEdge.class);
		
		Set<String> s1, s2;
		s2 = new LinkedHashSet<String>();
		s2.add("y");
		s2.add("z");
		
		sg.addVertex(s2);
		
		s2.remove("z");
		
		// this is true, as expected
		assert(sg.vertexSet().size()==1) : "There is no vertex any more.";
		assert(sg.vertexSet().iterator().next()==s2) : "Not the same vertex!";
		
		// but this is false!
		assert(sg.containsVertex(s2)) : "The vertex is gone!";
	}
}