split text with delimeters

Split.java

public class Split {
    public static Pattern whitespace = Pattern.compile("\\s+");

    public static void main(String[] s) {
        List<Block> blocks = splitWithDelimiters("r2ejh2j    24  3");
        blocks = splitWithDelimiters("СЛОН ТОПТПАИТ    24  3343");
        blocks = splitWithDelimiters("        топтает     ");
        blocks = splitWithDelimiters(" тооп");
        blocks = splitWithDelimiters("        ");
        blocks = splitWithDelimiters("");
        blocks = splitWithDelimiters("NODELIMETER");
    }


    String obfuscate(String data) {
        return data;
    }

    static List<Block> splitWithDelimiters(String s) {
        if (s == null || s.isEmpty())
            return Collections.emptyList();
        LinkedList<Block> blocks = new LinkedList<Block>();
        Matcher matcher = whitespace.matcher(s);
        boolean found;
        do {
            found = matcher.find();
            if (found) {
                blocks.add(new Block(matcher.start(), matcher.end(),
                        s.substring(matcher.start(), matcher.end()),
                        true));
            }
        } while (found);
        int lastMatched = -1;
        int from;
        int to;
        ListIterator<Block> it = blocks.listIterator();
        while (it.hasNext()) {
            Block next = it.next();
            if (next.whiteSpace) {
                from = lastMatched + 1;
                to = next.from;
                lastMatched = next.to - 1;
                if (to - from > 0) {
                    it.previous();
                    it.add(new Block(from, to, s.substring(from, to), false));
                }
            }
        }

        //EOL
        from = lastMatched + 1;
        to = s.length();

        if (to - from > 0) {
            it.add(new Block(from, to,
                    s.substring(from, to), false));
        }
        return blocks;
    }

    static class Block {
        final int from;
        final int to;
        final String text;
        final boolean whiteSpace;

        public Block(int from, int to, String text, boolean whiteSpace) {
            this.from = from;
            this.to = to;
            this.text = text;
            this.whiteSpace = whiteSpace;
        }
    }
}