PathIterator.java

//import org.apache.zookeeper.common.PathUtils;

import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

public final class PathIterator implements Iterator<String>, Iterable<String> {
    public static final String SEP = "/";
    private String[] znodes;
    private int end = -1;

    public PathIterator(String path) {
  //      PathUtils.validatePath(path);
        znodes = path.split("/");
        // skip first array element, that is empty
        if (znodes.length > 1) {
            znodes = Arrays.copyOfRange(znodes, 1, znodes.length);
        }
        end = znodes.length;
    }

    @Override
    public boolean hasNext() {
        return end >= 0;
    }

    public boolean atParentPath() {
        return end != znodes.length;
    }

    @Override
    public String next() {
        String localPath = joinZPath(znodes, end);
        if (hasNext()) {
            end--;
        }
        else {
            throw new NoSuchElementException();
        }
        return localPath;
    }

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

    private static String joinZPath(String[] znodes, int end) {
        int counter = 0;
        if (end == 0 && counter == 0) {
            return SEP;
        }
        else {
            StringBuilder sb = new StringBuilder();
            for (String znode : znodes) {
                if (end < 0 || counter < end) {
                    sb.append(SEP).append(znode);
                } else {
                    break;
                }
                counter++;
            }
            return sb.toString();
        }
    }
}

joinZPath with a negative end will print the whole path. OTOH, end >= 0 will print the portion of the path up to end value.