public void validatePage() {

    StatusInfo si = new StatusInfo(StatusInfo.OK, "");

    if (patternText != null) {
      String patternName = patternText.getText();
      if (patternName == null || patternName.length() == 0) {
        if (parameterSet) {
          si.setError(PATTERN_NAME_MUST_BE_SPECIFIED);
        } else {
          si.setWarning(PATTERN_NAME_SHOULD_BE_SPECIFIED);
        }
      }
    }

    if (si.getSeverity() == IStatus.OK) {
      si.setInfo("");
    }

    updateStatus(si);

    if (si.isError()) {
      setErrorMessage(si.getMessage());
    }
  }