UI Validation not working in Swing MetaWidget

Question

I am using MetaWidget for Swing. I am able to generate the UI and the BeanBinding is working as well. However, the validations like Mandatory Field and Max Length do not work. I am expecting that the first line in the savePerson() method to throw an exception when I leave the "First Name" field blank. Can you kindly help? Is there a Jar file I am missing? Is there something I am missing in my code?

Main UI Class

public class MetaWidgetFrame extends JFrame {

    private JPanel contentPane;
    private SwingMetawidget metawidget = new SwingMetawidget();


    /**
     * Create the frame.
     */
    public MetaWidgetFrame() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new BorderLayout(0, 0));
        setContentPane(contentPane);

        JPanel contentPanel = new JPanel();
        contentPane.add(contentPanel, BorderLayout.CENTER);

        JPanel controlsPanel = new JPanel();
        contentPanel.setLayout(new BorderLayout(0, 0));

        contentPane.add(controlsPanel, BorderLayout.SOUTH);

        JButton btnSave = new JButton("Save");
        btnSave.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                savePerson();
            }
        });
        controlsPanel.add(btnSave);

        Person person = new Person();
        person.setUserID(new Integer(1));
        person.setFirstName("Raman");
        person.setLastName("C V");

        CompositeInspectorConfig inspectorConfig = new CompositeInspectorConfig().setInspectors(
                  new JpaInspector()
                , new PropertyTypeInspector()
                );

        BeansBindingProcessor bbp = new BeansBindingProcessor();


        metawidget.setInspector( new CompositeInspector( inspectorConfig ) );
        metawidget.addWidgetProcessor(new ReflectionBindingProcessor());
        metawidget.addWidgetProcessor(bbp);
        metawidget.setToInspect(person);

        contentPanel.add(metawidget, BorderLayout.CENTER);
        pack();
    }

    public void savePerson() {
        metawidget.getWidgetProcessor(BeansBindingProcessor.class).save(metawidget );
        Person personSaved = metawidget.getToInspect();
        System.out.println("" + personSaved);
    }
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MetaWidgetFrame frame = new MetaWidgetFrame();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
}

Entity Class

import static javax.persistence.GenerationType.IDENTITY;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "person", catalog = "mydb")
public class Person {

    private Integer userID;
    private String firstName;
    private String lastName;

    public Person() {
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)

    @Column(name = "userID", unique = true, nullable = false)
    public Integer getUserID() {
        return userID;
    }

    @Column(name = "firstName", nullable = false, length = 10)
    public String getFirstName() {
        return firstName;
    }

    @Column(name = "lastName", nullable = false, length = 45)
    public String getLastName() {
        return lastName;
    }

    public void setUserID(Integer userID) {
        this.userID = userID;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return "Person: "
                + "\n userID = " + userID  
                + "\n firstName = " + firstName  
                + "\n lastName = " + lastName;
    }
}

The Screen:

The Screen with First name Blanked Out

Console Output:

Person: 
 userID = 1
 firstName = 
 lastName = C V

Answer 1

The Swing framework does not support data binding or validation out-of-the-box. Therefore neither does SwingMetawidget.

However you can augment Swing with various third-party frameworks such as BeansBinding, Commons BeansUtils, JGoodies Validator or Commons Validator. And therefore you can apply Metawidget plugins for each of those technologies.

You are already applying the BeansBinding third-party plugin, so that your bindings work.

You need to also apply one of the validator plugins. Metawidget directly supports JGoodies Validator, Commons Validator, oVal and Hibernate Validator. Choose whichever suits your existing architecture. Or you can roll your own WidgetProcessor.