validate a table's cell using editors

Question

I have a Password field editor for my JTable. I want to display an error message if the text length is less than 8 bit when the user clicks to edit another field. I have tri

Answer 1

As I understand the question, it's about validating the input in the editor (the model protecting itself against invalid values is another story, IMO) and notifying the user about his/her error when s/he tries to commit the input.

A simple means of doing so is using an InputVerifier:

• implement the validation rule in its verify method
• implement the notification in its shouldYieldFocus
• subclass DefaultCellEditor and override its stopCellEditing to call shouldYieldFocus and return its result (aka: refuse to commit the edit)

Some code snippet:

final InputVerifier iv = new InputVerifier() {

    @Override
    public boolean verify(JComponent input) {
        JTextField field = (JTextField) input;
        return field.getText().length() > 8;
    }

    @Override
    public boolean shouldYieldFocus(JComponent input) {
        boolean valid = verify(input);
        if (!valid) {
            JOptionPane.showMessageDialog(null, "invalid");
        }
        return valid;
    }

};
DefaultCellEditor editor = new DefaultCellEditor(new JTextField()) {
    {
        getComponent().setInputVerifier(iv);
    }

    @Override
    public boolean stopCellEditing() {
        if (!iv.shouldYieldFocus(getComponent())) return false;
        return super.stopCellEditing();
    }

    @Override
    public JTextField getComponent() {
        return (JTextField) super.getComponent();
    }

};

JTable table = new JTable(10, 2);
table.setDefaultEditor(Object.class, editor);