Typoglycemia

Typoglycemia.java

import java.util.*;

/**
 * User: zhaoyao
 * Date: 11/5/12
 * Time: 11:56 PM
 */
public class Typoglycemia {

    private static final Random rnd = new Random();

    public static void swap(char[] chars, int i, int j) {
        char tmp = chars[i];
        chars[i] = chars[j];
        chars[j] = tmp;
    }

    private static void shuffle(char[] chars, int from, int until) {
        int rndRange = until - from;
        for (int i = until-1; i >= from; i--) {
            int r = rnd.nextInt(rndRange) + from + 1;
            swap(chars, i, r);
        }
    }

    private static boolean isLetter(char c) {
        return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
    }

    public static String makeTypoglycemia(String para) {
        char[] chars = para.toCharArray();

        int len = chars.length;
        int from = 0;

        while (true) {
            // find word start
            while (from < len && !isLetter(chars[from])) {
                from++;
            }

            if (from == len) {
                break;
            }

            // find word end
            int until = from + 1;
            while (until < len && isLetter(chars[until])) {
                until++;
            }

            if (until - from >= 4) {
                shuffle(chars, from+1, until-1);
            }

            from = until;
        }

        return new String(chars);
    }

    public static void main(String[] args) {
        String input = "I couldn't believe that I could actually understand what I was reading: the phenomenal power of the\n" +
                       " human mind. According to a research team at Cambridge University, it doesn't matter in what order\n" +
                       " the letters in a word are, the only important thing is that the first and last letter be in the right\n" +
                       " place. The rest can be a total mess and you can still read it without a problem. This is because the\n" +
                       " human mind does not read every letter by itself, but the word as a whole. Such a condition is appropriately\n" +
                       " called Typoglycemia. Amazing, huh? Yeah and you always thought spelling was important.";


        makeTypoglycemia(input);


    }


}