/** Create a filter that will match a given family, qualifier, and cells per qualifier. */
 private RowFilter createColumnSpecFilter(SingleColumnValueFilter filter) throws IOException {
   return RowFilter.newBuilder()
       .setChain(
           Chain.newBuilder()
               .addFilters(
                   RowFilter.newBuilder()
                       .setFamilyNameRegexFilter(
                           Bytes.toString(quoteRegularExpression(filter.getFamily()))))
               .addFilters(
                   RowFilter.newBuilder()
                       .setColumnQualifierRegexFilter(
                           ByteStringer.wrap(quoteRegularExpression(filter.getQualifier()))))
               .addFilters(createVersionLimitFilter(filter)))
       .build();
 }
 private RowFilter createFamilyFilter(byte[] familyName) {
   return RowFilter.newBuilder()
       .setFamilyNameRegexFilterBytes(ByteStringer.wrap(quoteRegex(familyName)))
       .build();
 }
 private RowFilter createColumnQualifierFilter(byte[] unquotedQualifier) {
   return RowFilter.newBuilder()
       .setColumnQualifierRegexFilter(ByteStringer.wrap(quoteRegex(unquotedQualifier)))
       .build();
 }