code: public EntityScannerBuilder<E> addRegexMatchFilter(String fieldName,
        String regexString) {
      RegexEntityFilter regexEntityFilter = new RegexEntityFilter(
          entityMapper.getEntitySchema(), entityMapper.getEntitySerDe(),
          fieldName, regexString);
      filterList.add(regexEntityFilter.getFilter());
      return this;
    }
docs: Add a Regex Equality Filter to the Scanner, Will Filter Results Not Equal
  to the Filter Value
  
  @param fieldName
  The name of the column you want to apply the filter on
  @param filterValue
  The regular expression to use for comparison
  @return ScannerBuilder