question: public String next ( ) { seq += inc ; if ( seq >= maxSeq ) { randomizePrefix ( ) ; resetSequential ( ) ; } char [ ] b = new char [ totalLen ] ; System . arraycopy ( pre , 0 , b , 0 , preLen ) ; int i = b . length ; for ( long l = seq ; i > preLen ; l /= base ) { i -- ; b [ i ] = digits [ ( int ) ( l % base ) ] ; } return new String ( b ) ; }
target:  Generate the next NUID string from this instance.