return null;
if (root == null) throw new IllegalArgumentException ("focus cycle root is null"); if (current == null) throw new IllegalArgumentException ("current component is null");  if (!root.isFocusCycleRoot ()) throw new IllegalArgumentException ("root is not a focus cycle root");  Container ancestor = current.getFocusCycleRootAncestor (); Container prevAncestor = ancestor; while (ancestor != root) { ancestor = current.getFocusCycleRootAncestor (); if (ancestor == prevAncestor) {   if (ancestor != root) throw new IllegalArgumentException ("the given container is not" + " a focus cycle root of the" + " current component"); else break; } prevAncestor = ancestor;
  public Component getComponentAfter(Container root, Component current)  {    return null;  }