使用ComboBox的自动完成功能,同时将值限制为列表中的值？

import javax.swing.*;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Arrays;

public class ComboBoxExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("ComboBox Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);

        String[] items = {"apple", "banana", "cherry", "date", "elderberry", "fig"};

        JComboBox<String> comboBox = new JComboBox<>(items);
        comboBox.setEditable(true);

        JTextField textField = (JTextField) comboBox.getEditor().getEditorComponent();
        textField.getDocument().addDocumentListener(new DocumentListener(comboBox));

        frame.getContentPane().add(comboBox, BorderLayout.NORTH);

        frame.setVisible(true);
    }

    private static class DocumentListener implements javax.swing.event.DocumentListener {
        private JComboBox<String> comboBox;

        public DocumentListener(JComboBox<String> comboBox) {
            this.comboBox = comboBox;
        }

        @Override
        public void insertUpdate(javax.swing.event.DocumentEvent e) {
            updateComboBox(e);
        }

        @Override
        public void removeUpdate(javax.swing.event.DocumentEvent e) {
            updateComboBox(e);
        }

        @Override
        public void changedUpdate(javax.swing.event.DocumentEvent e) {
            updateComboBox(e);
        }

        private void updateComboBox(javax.swing.event.DocumentEvent e) {
            Document doc = e.getDocument();
            String text = "";
            try {
                text = doc.getText(0, doc.getLength());
            } catch (BadLocationException ex) {
                ex.printStackTrace();
            }

            JComboBox<String> combo = (JComboBox<String>) e.getDocument().getProperty("combo");
            if (combo != null) {
                String[] items = (String[]) combo.getItemAt(0);
                combo.removeAllItems();
                for (String item : items) {
                    if (item.toLowerCase().contains(text.toLowerCase())) {
                        combo.addItem(item);
                    }
                }
                if (combo.getItemCount() == 0) {
                    combo.addItem("No matches found");
                }
            }
        }
    }
}