如何让InputVerifier与可编辑的JComboBox一起使用

import javax.swing.*;
import java.awt.*;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Editable JComboBox with InputVerifier");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JComboBox<String> comboBox = new JComboBox<>(new String[]{"Option 1", "Option 2", "Option 3"});
        comboBox.setEditable(true);

        InputVerifier inputVerifier = new CustomInputVerifier();
        comboBox.setInputVerifier(inputVerifier);

        frame.getContentPane().add(comboBox, BorderLayout.NORTH);
        frame.pack();
        frame.setVisible(true);
    }
}

class CustomInputVerifier extends InputVerifier {
    @Override
    public boolean verify(JComponent input) {
        JComboBox comboBox = (JComboBox) input;
        String selectedItem = (String) comboBox.getSelectedItem();
        return selectedItem != null && !selectedItem.isEmpty();
    }
}