/**
   * Contains the logic that recognizes a single word.
   */
  private static final class SingleWordMatcher {
    private static final Logger LOG = LoggerFactory.getLogger(SearchStringAnalyzer.SingleWordMatcher.class);
    private static final String SINGLE_WORD_PATTERN_STRING = "^[a-zA-Z][a-zA-Z0-9]*$";
    private static final Pattern SINGLE_WORD_PATTERN = Pattern.compile(SINGLE_WORD_PATTERN_STRING);
    private SingleWordMatcher() {
    }

    /**
     * Determines whether the inputString contains a single word.
     *
     * @param inputString
     * @return true when the inputString is considered to be a single word.
     */
    static boolean isSingleWord(final String inputString) {
      final boolean result;
      try {
        final Matcher matcher = SINGLE_WORD_PATTERN.matcher(inputString);
        return matcher.find();
      } catch (final PatternSyntaxException pse) {
        result = false;
        LOG.error(REGEX_PROBLEM,
            pse.getPattern(), pse.getDescription(), pse.getMessage(), pse.getIndex(), pse);
      }
      return result;
    }
  }