Autocomplete Textbox with Drop down JList, Highlight on Mouseover

Question

import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.DefaultListModel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.JWindow;
import javax.swing.ListSelectionModel;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class CompletableJTextField extends JTextField implements ListSelectionListener {
     private static final long serialVersionUID = 1L;
     private Completer completer;
     private JList completionList;
     private DefaultListModel completionListModel;
     private JScrollPane listScroller;
     private JWindow listWindow;
     public CompletableJTextField(int col){
          super(col);
          completer = new Completer();
          completionListModel = new DefaultListModel();
          completionList = new JList(completionListModel);
          completionList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
          completionList.addListSelectionListener(this);
          // highlights item on mouse-over
          completionList.addMouseMotionListener(new MouseAdapter() {
               public void mouseMoved(MouseEvent me) {
                    Point p = new Point(me.getX(),me.getY());
                    completionList.setSelectedIndex(completionList.locationToIndex(p));
          // selects an item when clicked
          completionList.addMouseListener(new MouseListener(){
               public void mouseClicked(MouseEvent me) {
                    Point p = new Point(me.getX(),me.getY());
                    completionList.setSelectedIndex(completionList.locationToIndex(p));
                    makeSelection();
               public void mouseEntered(MouseEvent me) {}
               public void mouseExited(MouseEvent arg0) {}
               public void mousePressed(MouseEvent arg0) {}
               public void mouseReleased(MouseEvent arg0) {}
          listScroller = new JScrollPane(completionList, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
                                                                    ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
          listWindow = new JWindow();          
          listWindow.getContentPane().add(listScroller);
     public void setBounds(int x, int y, int w, int h){
          super.setBounds(x, y, w, h);
          listScroller.setPreferredSize(new Dimension(w,200));
     public void addCompletion(String s) { completer.addCompletion(s); }
     public void removeCompletion(String s) { completer.removeCompletion(s); }
     public void clearCompletions(){ completer.clearCompletions(); }
     public void makeSelection(){
          listWindow.setVisible(false);
          final String completionString = (String) completionList.getSelectedValue();
          Thread worker = new Thread(){
               public void run(){
                    setText(completionString);
          SwingUtilities.invokeLater(worker);
     public void valueChanged(ListSelectionEvent e) {
          if(e.getValueIsAdjusting()) return;
          if(completionList.getModel().getSize() == 0) return;
     private class Completer implements DocumentListener{
          private Pattern pattern;
          private ArrayList<String> completions;
          public Completer(){
               completions = new ArrayList<String>();
               getDocument().addDocumentListener(this);
          public void addCompletion(String s){
               completions.add(s);
               buildAndShowPopup();
          public void removeCompletion(String s){
               completions.remove(s);
               buildAndShowPopup();
          public void clearCompletions(){
               completions.clear();
               buildAndShowPopup();
               listWindow.setVisible(false);
          private void buildPopup(){
               completionListModel.clear();
               Iterator<String> it = completions.iterator();
               pattern = Pattern.compile(getText() + ".+");
               while(it.hasNext()){
                    String completion = it.next();
                    Matcher matcher = pattern.matcher(completion);
                    if(matcher.matches()){
                         completionListModel.add(completionListModel.getSize(), completion);
          private void showPopup(){
               if(completionListModel.getSize() == 0){
                    listWindow.setVisible(false);
                    return;
               Point los = getLocationOnScreen();
               int popX = los.x;
               int popY = los.y + getHeight();
               listWindow.setLocation(popX, popY);
               listWindow.pack();
               listWindow.setVisible(true);
          private void buildAndShowPopup(){
               if(getText().length() < 1) return;
               buildPopup();
               showPopup();
          public void changedUpdate(DocumentEvent e) {buildAndShowPopup();}
          public void insertUpdate(DocumentEvent e) {buildAndShowPopup();}
          public void removeUpdate(DocumentEvent e) {buildAndShowPopup();}
}

Answer 1

This component still a lot to be desired in terms of functionality. One immediately missing feature is the ability scroll up and down the List with the keyboard.
I seen most of the functionality previously implemented, (I believe keybinds were added to the document in order for it to be able to forward the scroll commands to the List).
I'm sure you can work it out. All the best
ICE