code: public int getRevision(String field) {
          getSignatureNames();
          field = getTranslatedFieldName(field);
          if (!sigNames.containsKey(field))
              return 0;
          return ((int[])sigNames.get(field))[1];
      }
docs: Gets this <CODE>field</CODE> revision.
  
  @param field the signature field name
  @return the revision or zero if it's not a signature field