@Override
          public IterationMode nextEdge(EdgeType edge) {
            if (edge.isVisible()) {
              edges.add(edge);
            }
            return IterationMode.CONTINUE;
          }
Returns a <code>Collection</code> of all visible edges of the specified graph.

@param graph the graph that contains the edges
@return a <code>Collection</code> containing all visible edges of the graph. May be empty.
java/ui/src/main/java/com/google/security/zynamics/bindiff/graph/filter/GraphEdgeFilter.java