public void addMasterNodes(Collection<GraphNode> result){
  for (  GraphNode master : collapsedData.keySet()) {
    result.add(master);
  }
}

public void addMasterNodes ( Collection < GraphNode > result ) { for ( GraphNode master : collapsedData . keySet ( ) ) { result . add ( master ) ; } }
add the master nodes to a collections of nodes . this is often one step in building the set of visible nodes for an entire viewmodel .
