private void addPrefixOption(String arg) {
    int i = arg.indexOf('=');
    if (i < 1) {
      usage("invalid prefix format");
    }
    packagePrefixes.addPrefix(arg.substring(0, i), arg.substring(i + 1));
  }
private void addPrefixOption ( String arg ) { int i = arg . indexOf ( '=' ) ; if ( i < 1 ) { usage ( "invalid prefix format" ) ; } packagePrefixes . addPrefix ( arg . substring ( 0 , i ) , arg . substring ( i + 1 ) ) ; }
Add prefix option, which has a format of "<package>=<prefix>".