DefaultGeoJsonLoader loader = (DefaultGeoJsonLoader) vectorSource.getLoader();
if (layerDataLoadedMap.get(layer) != null) {
// add our listener for the feature data loading
loader.vectorFeatureDataLoadedListener(layerDataLoadedMap.get((Vector) layer));
}
if (layerLoadedMap.get(layer) != null) {
// add our listener for the feature loading