code: @Override
      protected boolean hasTileToRetrieve(int x, int y, int zoom) {
          boolean hasTile = false;
          for (BoundedOverlay overlay : overlays) {
              hasTile = overlay.hasTileToRetrieve(x, y, zoom);
              if (hasTile) {
                  break;
              }
          }
          return hasTile;
      }
docs: {@inheritDoc}