public abstract class SuperUser {
    
    protected String userName;
    protected String firstName;
    protected String lastName;
    
    public SuperUser(String uName, String fName, String lName) throws InvalidUserException {
        userName = uName;
        firstName = fName;
        lastName = lName;
        
        if (userName == null || userName.equals("")) {
            throw new Shared.Exceptions.InvalidUserException("User with empty username");
        }
    }

    public String getUserName() {
        return userName;
    }

    public String getFirstName() {
        return firstName;
    }
    
    public String getLastName() {
        return lastName;
    }
    
    public String toString() {
        return this.getClass() + " Username = " + userName + " first name = " + firstName + " last name = " + lastName;
    }
}





==================================================================================





public class UserSignature extends SuperUser {

    private String password;
    private TreeMap applications;
    private int hashcode;
    
    public UserSignature(Element userElement) throws InvalidUserException {
        super(userElement.getAttribute("username").trim(), userElement.getAttribute("firstname").trim(), userElement.getAttribute("lastname").trim());
        
        password = userElement.getAttribute("password").trim();
        
        NodeList nodes = userElement.getElementsByTagName("application");
        applications = new TreeMap();
        
        for (int i = 0; i < nodes.getLength(); i++) {
            Element e = (Element)nodes.item(i);
            applications.put(e.getAttribute("name").trim(), e.getAttribute("role").trim());
        }
        
        hashcode = userName.hashCode();
    }
    
    public UserSignature(Task t) throws InvalidUserException {
        try { super(t.getUserName(), "", ""); }
        catch (InvalidUserException iue) { throw new InvalidTaskException(); }
        
        hashcode = userName.hashCode();
    }
    
    public int hashCode() {
        return hashcode;
    }
    
    public boolean containsApplication(String appName) {
        return applications.containsKey(appName);
    }
    
    public boolean checkPassword(String apassword) {
        if (apassword != null) {
            return apassword.equals(password);
        } else return false;
    }
    
    public String toString() {
        return super.toString() + applications.toString();
    }
}