code: public QueryParser getParserFor( String language ) {
          CheckArg.isNotNull(language, "language");
          return parsers.get(language.trim().toLowerCase());
      }
docs: Get the parser for the supplied language.
  
  @param language the language in which the query is expressed; must case-insensitively match one of the supported
  {@link #getLanguages() languages}
  @return the query parser, or null if the supplied language is not supported
  @throws IllegalArgumentException if the language is null