public void addConnectionCallback(OneSheeldConnectionCallback connectionCallback){
  if (connectionCallback != null && !connectionCallbacks.contains(connectionCallback))   connectionCallbacks.add(connectionCallback);
}

public void addConnectionCallback ( OneSheeldConnectionCallback connectionCallback ) { if ( connectionCallback != null && ! connectionCallbacks . contains ( connectionCallback ) ) connectionCallbacks . add ( connectionCallback ) ; }
add a connection callback .
