code: private void validateFacetFields(String[] facetFieldList) {
          if(facetFieldList == null || facetFieldList.length == 0){
              return;
          }
          for (String facetfield : facetFieldList){
              if(schema.getColumnIndex(facetfield) < 0){
                  throw new IllegalArgumentException("Facet field:"+facetfield+", not found in schema");
              }
          }
  
      }
docs: Check each facet field is present in schema.
  @param facetFieldList an array of facet fields