public class Synchronizer {
    public final String targetHash;
    private Long solution = null;

    public Synchronizer(String hash) { targetHash = hash; }

    public synchronized void setSolution(long password)
    {
	solution = password;
	this.notifyAll();
    }

    public synchronized long getSolution()
    {
	return solution;
    }

    public synchronized boolean hasSolution()
    {
	return (solution != null);
    }
}