how to implement custom DefaultComboBoxModel - swing

Question

I'm need to implement my custom DefaultComboboxModel. Reason for doing this is that every time I call the
DefaultComboBoxModel model = (DefaultComboBoxModel)getModel();
model.removeAllElements();
or
model.addElement(Object);
or
model.insertElementAt(Object,int)
I see that it automatically fires an ItemStateChanged event. This is causing some random item to automatically get selected from the list. This is not what I want, since it populates the editable JTextField with random selected item.
This is the stacktrace I see when debugging using Thread.dumpStack() from my custom Itemlistener that I see when calling above methods:
at javax.swing.JComboBox.fireItemStatehanged(Unknown source)
at javax.swing.JComboBox.selectedItemChanged(Unknown source)
at javax.swing.JComboBox.contentsChanged(Unknown source)
at javax.swing.JComboBox.fireContentsChanged(Unknown source)
at javax.swing.JComboBox.setSelectedItem(Unknown source)
at javax.swing.JComboBox.addElement(Unknown source)
I already tried using setSelectedIndex(-1) before updating model and also after model has been updated, but same problem. I guess having my custom model is the way to go.
Question is how do I implement my custom combo box model? Do I just extend DefaultComboBoxModel? Do I have to override all methods from DefaultComboBoxMode?
Below is what I have so far. But if you see below, I dont have a reference to the actual Vector list to remove the item. If I declare a Vector list field in my custom AutocompleteComboBoxModel, then do I need to override all methods to avoid other SWING code from referencing the Vector in super class?
Remember my goal is to NEVER allow the model to automatically call setSelectedItem(Object), since this seem to be causing problem, unless there is a better way to do this.
public class AutocompleteComboBoxModel extends DefaultComboBoxModel{
public void removeElementAt(int index){
list.removeElementAt(index);
fireIntervalRemoved(this, index, index);
}
}
Also this is how I'm calling the method that does the model manipulation:
public class AutocompleteDocumentListener implementts DocumentListener{
JTextField tf;
public AutocompleteDocumentListener (JTextfield tf){
this.tf = tf;
}
#Override
public void changedUpdate(DocumentEvent e){
}
#Override
public void insertUpdate(DocumentEvent e){
update();
}
#Override
public void removeUpdate(DocumentEvent e){
update();
}
public void update(){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
performSearch(tf.getText());//Search user input
}
)
}
}
EDIT: just want to mention that this weird behavior only occurs when I type very fast. If I type slow, then SWING does not autoselect a random item. So why would this occur when typing fast if I'm using the SwingUtlities.invokeLater? Currently when SWING calls the setSelectedItem(Object), will this fired event execute before other invokeLater requests?
EDIT: I'm removing the ItemListener and still not working. I then kept going and removed the JComboBox KeyListeners, ActionListeners, ComponentListeners and FocusListeners and still it auto selects Item. It seems that sometime after the invokeLater is done that I see the item being selected, probably as I'm still typing on the JTextField:
java.lang.Exception: Stack trace
at java.lang.Thread.dumpStack(Unknown Source)
at com.artificialmed.coderdx.encoder.TermSelectionListener.itemStateChanged(TermSelectionListener.java:23)
at javax.swing.JComboBox.fireItemStateChanged(Unknown Source)
at javax.swing.JComboBox.selectedItemChanged(Unknown Source)
at javax.swing.JComboBox.contentsChanged(Unknown Source)
at javax.swing.AbstractListModel.fireContentsChanged(Unknown Source)
at javax.swing.DefaultComboBoxModel.setSelectedItem(Unknown Source)
at javax.swing.JComboBox.setSelectedItem(Unknown Source)
at javax.swing.JComboBox.setSelectedIndex(Unknown Source)
at javax.swing.JComboBox.selectWithKeyChar(Unknown Source)
at javax.swing.plaf.basic.BasicComboBoxUI$Handler.keyPressed(Unknown Source)
at java.awt.Component.processKeyEvent(Unknown Source)
at javax.swing.JComponent.processKeyEvent(Unknown Source)
at javax.swing.JComboBox.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Thanks in advance.

Answer 1

The addElement(...) or insertElementAt(...) methods should not cause an ItemStateChanged event to be generated since the selection should not change.
The removeAll() elements would cause the selected item to be unselected so it makes sense that an event is generated.
A couple of solutions:
only handle the "item selected" event. This way when you remove all the items you ignore the "item deselected" event.
In your logic that gets invoked when the state changes your code should invoke getSelectedItem(). If this value is null, then you don't do anything.
a) remove the listener, b) invoke the removeAll() method, c) add the listener. Since the listener doesn't exist at the time the removeAll() method is invoked no events will be generated.