code: public Date getSubAttrAsDate(String attrName, String dPath, String dateTimeFormat) {
          Lock lock = lockForRead();
          try {
              return JacksonUtils.getDate(getAttribute(attrName), dPath, dateTimeFormat);
          } finally {
              lock.unlock();
          }
      }
docs: Get a sub-attribute as a date using d-path. If sub-attr's value is a
  string, parse it as a {@link Date} using the specified date-time format.
  
  @param attrName
  @param dPath
  @param dateTimeFormat
  @return