private void graphChanged(Node from,Node to){
  for (  DependencyKind dk : removeDependency(from)) {
    if (to != null) {
      addDependency(dk,to);
    }
  }
}

private void graphChanged ( Node from , Node to ) { for ( DependencyKind dk : removeDependency ( from ) ) { if ( to != null ) { addDependency ( dk , to ) ; } } }
notify all nodes that something has changed in the graph topology .
