import java.util.Iterator;
import java.util.NoSuchElementException;

public class Sentence implements Iterable<String> {

    private String s;

    Sentence(String s) {
        this.s = s;
    }

    @Override
    public Iterator<String> iterator() {
        return new PalindromeIterator();
    }

    @Override
    public String toString() {
        return s;
    }

    private class PalindromeIterator implements Iterator<String> {

        private int pos;

        PalindromeIterator() {
            pos = 0;
        }

        @Override
        public boolean hasNext() {
            while (true) {
                while (pos < s.length() && s.charAt(pos) == ' ') {
                    pos++;
                }
                if (pos == s.length()) {
                    return false;
                }
                int i = pos, j = 0;
                while (i < s.length() && s.charAt(i) != ' ') {
                    i++;
                }
                i--;
                while (pos + j < i - j && s.charAt(pos + j) == s.charAt(i - j)) {
                    j++;
                }
                if (pos + j >= i - j) {
                    return true;
                } else {
                    pos = i + 2;
                }
            }
        }

        @Override
        public String next() {
            while (true) {
                while (pos < s.length() && s.charAt(pos) == ' ') {
                    pos++;
                }
                if (pos == s.length()) {
                    throw new NoSuchElementException();
                }
                int i = pos, j = 0;
                while (i < s.length() && s.charAt(i) != ' ') {
                    i++;
                }
                i--;
                while (j * 2 < i - pos && s.charAt(pos + j) == s.charAt(i - j)) {
                    j++;
                }
                j = pos;
                pos = i + 2;
                if (pos + j >= i - j) {
                    return s.substring(j, i + 1);
                }
            }
        }

    }

}
public class Test {

    public static void main(String[] args) {
        Sentence s = new Sentence("hello   world x  abcdcba 1232321  1243421        11  ");
        System.out.println("Предложение: " + s);
        System.out.print("Палиндромы:");
        for (String palindrome : s) {
            System.out.print("  " + palindrome);
        }
    }

}