Это небольшой пример реализации того, что (я думаю) вы просили ... база данных в этом примере - это вектор строк.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Answer extends JFrame {
public static final int MAXITEMS = 100;
JPanel panel = new JPanel();
JTextField textField = new JTextField(10);
String[] myDataBase = { "Juby", "Jaz", "Jasmine", "Joggy", "one", "dog","cat", "parot" };
String[] listItems;
JList theList = new JList();
public Answer() {
this.add(panel);
panel.setPreferredSize(new Dimension(500, 300));
panel.add(textField);
panel.add(theList);
textField.addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent ke) {
String compareString = ("" + textField.getText() + ke.getKeyChar());
listItems = new String[MAXITEMS];
if (compareString.trim().length() > 0 ){
int counter = 0;
for (int i = 0; i < myDataBase.length; i++) {
if (counter < MAXITEMS) {
if (myDataBase[i].length() >= compareString.length() &&
myDataBase[i].substring(0, compareString.length()).equalsIgnoreCase(compareString)) {
listItems[counter] = myDataBase[i];
counter++;
}
}
}
}
theList.setListData(listItems);
}
});
}
public static void main(String[] args) {
final Answer answer = new Answer();
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
answer.pack();
answer.setVisible(true);
}
});
}
}