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/*
Definitive Guide to Swing for Java 2, Second Edition
By John Zukowski
ISBN: 1-893115-78-X
Publisher: APress
*/
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.ComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.Timer;
public class MultiKeyCombo {
public static void main(String args[]) {
String labels[] = { "One", "Only", "Once", "Okay", "oneself",
"onlooker", "Onslaught", "Onyx", "onus", "onward" };
JFrame f = new JFrame("Example JList");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComboBox jc = new JComboBox(labels);
MultiKeySelectionManager mk = new MultiKeySelectionManager();
jc.setKeySelectionManager(mk);
// jc.setKeySelectionManager (new JComboBox.KeySelectionManager() {
// public int selectionForKey (char aKey, ComboBoxModel aModel) {
// return -1;
// }
// });
Container c = f.getContentPane();
c.add(jc, BorderLayout.NORTH);
f.setSize(200, 200);
f.setVisible(true);
}
}
class MultiKeySelectionManager implements JComboBox.KeySelectionManager {
private StringBuffer currentSearch = new StringBuffer();
private Timer resetTimer;
private final static int RESET_DELAY = 3000;
public MultiKeySelectionManager() {
resetTimer = new Timer(RESET_DELAY, new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
currentSearch.setLength(0);
}
});
}
public int selectionForKey(char aKey, ComboBoxModel aModel) {
// Reset if invalid character
if (aKey == KeyEvent.CHAR_UNDEFINED) {
currentSearch.setLength(0);
return -1;
}
// Since search, don't reset search
resetTimer.stop();
// Convert input to uppercase
char key = Character.toUpperCase(aKey);
// Build up search string
currentSearch.append(key);
// Find selected position within model to starting searching from
Object selectedElement = aModel.getSelectedItem();
int selectedIndex = -1;
if (selectedElement != null) {
for (int i = 0, n = aModel.getSize(); i < n; i++) {
if (aModel.getElementAt(i) == selectedElement) {
selectedIndex = i;
break;
}
}
}
boolean found = false;
String search = currentSearch.toString();
// Search from selected forward, wrap back to beginning if not found
for (int i = 0, n = aModel.getSize(); i < n; i++) {
String element = aModel.getElementAt(selectedIndex).toString()
.toUpperCase();
if (element.startsWith(search)) {
found = true;
break;
}
selectedIndex++;
if (selectedIndex == n) {
selectedIndex = 0; // wrap
}
}
// Restart timer
resetTimer.start();
return (found ? selectedIndex : -1);
}
}
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