*   <li>{@link #getQueryWordsNum()}: Returns the number of query words in the suggestion index.</li>
 * </ul>
 *
 * <p>Protected Methods:
 * <ul>
 *   <li>{@link #createDefaultIndexer()}: Creates a default SuggestIndexer instance.</li>
 * </ul>
 *
 * <p>Private Methods:
 * <ul>
 *   <li>{@link #getNum(QueryBuilder)}: Returns the number of words matching the given query.</li>