public boolean isVisited(String uri){
  if (uri == null)   return false;
  uri=resolveURI(uri);
  return history.contains(uri);
}

public boolean isVisited ( String uri ) { if ( uri == null ) return false ; uri = resolveURI ( uri ) ; return history . contains ( uri ) ; }
returns true if the link has been visited by the user in this session . visit tracking is not persisted .
