/**
  * Return set of filter names configured to work on top of given field name.
  *
  * @param fieldName
  * @return Set of filter names
  * @throws java.lang.RuntimeException if new request filters cache hasn't been initialized yet
  */
 public Set<String> getFilterNamesForDocumentField(String fieldName) {
   Set<String> filterNames = new HashSet<>();
   for (SemiParsedFilterConfig c : this.getFilterConfigsForRequest().values()) {
     if (c.getFieldName().equals(fieldName)) {
       filterNames.add(c.getFilterName());
     }
   }
   return filterNames;
 }