@Override
 public int getMinimumZoomLevel() {
   ITileSource tileSource = mTileSource.get();
   return tileSource != null
       ? tileSource.getMinimumZoomLevel()
       : OpenStreetMapTileProviderConstants.MINIMUM_ZOOMLEVEL;
 }
 @Override
 public int getMinimumZoomLevel() {
   return mTileSource != null ? mTileSource.getMinimumZoomLevel() : MAXIMUM_ZOOMLEVEL;
 }