protected static function ensure_collator_available() {
        $locale = get_string('locale', 'langconfig');
        if (is_null(self::$collator) || $locale != self::$locale) {
            self::$collator = false;
            self::$locale = $locale;
            if (class_exists('Collator', false)) {
                $collator = new Collator($locale);
                if (!empty($collator) && $collator instanceof Collator) {
                    // Check for non fatal error messages. This has to be done immediately
                    // after instantiation as any further calls to collation will cause
                    // it to reset to 0 again (or another error code if one occurred)
                    $errorcode = $collator->getErrorCode();
                    $errormessage = $collator->getErrorMessage();
                    // Check for an error code, 0 means no error occurred
                    if ($errorcode !== 0) {
                        // Get the actual locale being used, e.g. en, he, zh
                        $localeinuse = $collator->getLocale(Locale::ACTUAL_LOCALE);
                        // Check for the common fallback warning error codes. If any of the two
                        // following errors occurred, there is normally little to worry about:
                        // * U_USING_FALLBACK_WARNING (-128) indicates that a fall back locale was
                        //   used. For example, 'de_CH' was requested, but nothing was found
                        //   there, so 'de' was used.
                        // * U_USING_DEFAULT_WARNING (-127) indicates that the default locale
                        //   data was used; neither the requested locale nor any of its fall
                        //   back locales could be found. For example, 'pt' was requested, but
                        //   UCA was used (Unicode Collation Algorithm http://unicode.org/reports/tr10/).
                        // See http://www.icu-project.org/apiref/icu4c/classicu_1_1ResourceBundle.html
                        if ($errorcode === -127 || $errorcode === -128) {
                            // Check if the locale in use is UCA default one ('root') or
                            // if it is anything like the locale we asked for
                            if ($localeinuse !== 'root' && strpos($locale, $localeinuse) !== 0) {
                                // The locale we asked for is completely different to the locale
                                // we have received, let the user know via debugging
                                debugging('Locale warning (not fatal) '.$errormessage.': '.
                                    'Requested locale "'.$locale.'" not found, locale "'.$localeinuse.'" used instead. '.
                                    'The most specific locale supported by ICU relatively to the requested locale is "'.
                                    $collator->getLocale(Locale::VALID_LOCALE).'".');
                            } else {
                                // Nothing to do here, this is expected!
                                // The Moodle locale setting isn't what the collator expected but
                                // it is smart enough to match the first characters of our locale
                                // to find the correct locale or to use UCA collation
                            }
                        } else {
                            // We've received some other sort of non fatal warning - let the
                            // user know about it via debugging.
                            debugging('Problem with locale: '.$errormessage.'. '.
                                'Requested locale: "'.$locale.'", actual locale "'.$localeinuse.'". '.
                                'The most specific locale supported by ICU relatively to the requested locale is "'.
                                $collator->getLocale(Locale::VALID_LOCALE).'".');
                        }
                    }
                    // Store the collator object now that we can be sure it is in a workable condition
                    self::$collator = $collator;
                } else {
                    // Fatal error while trying to instantiate the collator... something went wrong
                    debugging('Error instantiating collator for locale: "' . $locale . '", with error [' .
                    intl_get_error_code() . '] ' . intl_get_error_message($collator));
                }
            }
        }
        return (self::$collator instanceof Collator);
    }