code: public boolean hasTile(BoundingBox requestBoundingBox) {
  
  		boolean hasTile = false;
  
  		// Transform to the projection of the tiles
  		ProjectionTransform transformRequestToTiles = requestProjection
  				.getTransformation(tilesProjection);
  		BoundingBox tilesBoundingBox = requestBoundingBox
  				.transform(transformRequestToTiles);
  
  		List<TileMatrix> tileMatrices = getTileMatrices(tilesBoundingBox);
  
  		for (int i = 0; !hasTile && i < tileMatrices.size(); i++) {
  
  			TileMatrix tileMatrix = tileMatrices.get(i);
  
  			TileResultSet tileResults = retrieveTileResults(tilesBoundingBox,
  					tileMatrix);
  			if (tileResults != null) {
  
  				try {
  					hasTile = tileResults.getCount() > 0;
  				} finally {
  					tileResults.close();
  				}
  			}
  		}
  
  		return hasTile;
  	}
docs: Check if the tile table contains a tile for the request bounding box
  
  @param requestBoundingBox
  request bounding box in the request projection
  @return true if a tile exists