I cannot explain this problem, and in searching all over I've seen a few leads but no help. I do not understand at all why I get this exception. It claims I am trying to cast a JList as a DefaultListModel when I'me trying to cast a ListModel and a DefaultListModel (yes, I instantiated the JList with a DefaultListModel).
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JList$4 cannot be cast to javax.swing.DefaultListModel
at SchoolClassDisplay.actionPerformed(SchoolClassDisplay.java:171)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(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.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(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.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)import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.JSeparator;
import javax.swing.JPanel;
import javax.swing.JList;
import javax.swing.WindowConstants;
import javax.swing.DefaultListModel;
import java.util.ArrayList;
public class SchoolClassDisplay implements ActionListener {
private SchoolClass schoolClass; //class being edited
private ActionListener ownerActionListener; //parent frame listener
private String saveOptionActionCommand; //command for parent frame notification
private String cancelOptionActionCommand; //command for parent frame notification
public SchoolClassDisplay (ActionListener ownerFrameActionListener, String saveClassCommand, String cancelClassCommand, SchoolClass schClass) throws NullPointerException {
/*if (ownerFrameActionListener == null)
throw new NullPointerException ("ownerFrameActionListener cannot be null");*/
if (saveClassCommand == null)
throw new NullPointerException ("saveTypeCommand cannot be null");
if (cancelClassCommand == null)
throw new NullPointerException ("cancelTypeCommand cannot be null");
schoolClass = schClass;
ownerActionListener = ownerFrameActionListener;
saveOptionActionCommand = saveClassCommand;
cancelOptionActionCommand = cancelClassCommand;
}
//GUI parts
private JFrame frame;
private JTextField name;
private JTextField location;
private JList times;
private JButton addTime; //open add time slot prompt
private JButton delTime;
private JButton save;
private JButton cancel;
private DayTimeDisplay dayTimeEditor; //time slot editor
private String saveDayTimeActionCommand = "saveDayTime";//command linking above to this
public void show() {
GridBagLayout gridBag = new GridBagLayout();
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = GridBagConstraints.BOTH;
gbc.anchor = GridBagConstraints.NORTHWEST;
frame = new JFrame ("Class Editor");
frame.setLayout(gridBag);
frame.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
if (schoolClass != null)
frame.setTitle(schoolClass.getName());
JLabel a = new JLabel("Name: ");
gbc.gridwidth = 1;
gridBag.setConstraints(a, gbc);
frame.add(a);
name = new JTextField("");
if (schoolClass != null)
name.setText(schoolClass.getName());
gbc.weightx = 1;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gridBag.setConstraints(name, gbc);
frame.add(name);
a = new JLabel("Location: ");
gbc.weightx = 0;
gbc.gridwidth = 1;
gridBag.setConstraints(a, gbc);
frame.add(a);
location = new JTextField("");
if (schoolClass != null)
location.setText(schoolClass.getLocation());
gbc.weightx = 1;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gridBag.setConstraints(location, gbc);
frame.add(location);
a = new JLabel("Times: ");
gbc.weightx = 0;
gbc.gridwidth = 1;
gridBag.setConstraints(a, gbc);
frame.add(a);
times = new JList(new DefaultListModel());
if (schoolClass != null)
times.setListData(schoolClass.getTimeSlots().toArray());
gbc.weightx = 1;
gbc.weighty = 1;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gridBag.setConstraints(times, gbc);
frame.add(times);
a = new JLabel(" ");
gbc.weightx = 0;
gbc.weighty = 1;
gbc.gridwidth = 1;
gridBag.setConstraints(a, gbc);
frame.add(a);
JPanel buttons1 = new JPanel(new GridLayout(1,2));
gbc.weightx = 1;
gbc.weighty = 1;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gridBag.setConstraints(buttons1, gbc);
frame.add(buttons1);
addTime = new JButton("Add");
addTime.addActionListener(this);
addTime.setActionCommand("addTime");
buttons1.add(addTime);
delTime = new JButton("Delete");
delTime.addActionListener(this);
delTime.setActionCommand("delTime");
buttons1.add(delTime);
JSeparator s = new JSeparator();
gbc.weightx = 0;
gbc.weighty = 0;
gridBag.setConstraints(s, gbc);
frame.add(s);
JPanel buttons2 = new JPanel(new GridLayout(1,2));
gridBag.setConstraints(buttons2, gbc);
frame.add(buttons2);
save = new JButton("Save");
save.addActionListener(this);
save.addActionListener(ownerActionListener);
save.setActionCommand(saveOptionActionCommand);
buttons2.add(save);
cancel = new JButton("Cancel");
cancel.addActionListener(this);
cancel.addActionListener(ownerActionListener);
cancel.setActionCommand(cancelOptionActionCommand);
buttons2.add(cancel);
JPanel blank = new JPanel();
blank.setPreferredSize(new java.awt.Dimension(0,0));
gbc.weightx = 1;
gbc.weighty = 1;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.gridheight = GridBagConstraints.REMAINDER;
gridBag.setConstraints(blank,gbc);
frame.add(blank);
frame.pack();
frame.setVisible(true);
}
public void actionPerformed (ActionEvent a) {
//open add time slot dialogue
if (a.getActionCommand().equals(addTime.getActionCommand())) {
frame.setEnabled(false);
dayTimeEditor = new DayTimeDisplay(this, saveDayTimeActionCommand, null);
dayTimeEditor.show();
}
//remove time slot
if (a.getActionCommand().equals(delTime.getActionCommand())) {
if (times.getSelectedIndex() != -1) {
((DefaultListModel)(times.getModel())).remove(times.getSelectedIndex());
}
}
//command received from time slot editor indicating "Add" pressed finalizing creation
if (a.getActionCommand().equals(saveDayTimeActionCommand)) {
frame.setEnabled(true);
frame.requestFocus();
DayTime oldDayTime = dayTimeEditor.getUneditedAssignment(); //store old if was editing mode
DayTime newDayTime = dayTimeEditor.getSavedAssignment();
if(newDayTime == null) //failed creation
return;
if (oldDayTime == null)
((DefaultListModel)(times.getModel())).addElement(newDayTime);
else {
int index = ((DefaultListModel)(times.getModel())).indexOf(oldDayTime);
((DefaultListModel)(times.getModel())).set(index, newDayTime);
}
}
}
//test purposes only
public static void main (String[] args) {
ArrayList<DayTime> daytimes = new ArrayList<DayTime>();
int[] days1 = {0,1,0,1,0,1,0};
int[] days2 = {0,0,1,0,1,0,0};
daytimes.add(new DayTime(days1,10,30));
daytimes.add(new DayTime(days2,14,30));
SchoolClass associatedClass1 = new SchoolClass("Math","School",daytimes);
SchoolClassDisplay a = new SchoolClassDisplay (null, "saveClass", "cancelClass", associatedClass1);
a.show();
}
}I tried to reproduce this problem in a very simple setting; the same basic thing is happening, lines 11 and 171 are identical and set up the same way. However, this brought NO exception. What is going on?
import javax.swing.*;
public class dfgdrtgrtg {
private JList times;
public dfgdrtgrtg () {
times = new JList(new DefaultListModel());
DefaultListModel listModel = (DefaultListModel)(times.getModel());
}
public static void main (String[] args) {
dfgdrtgrtg a = new dfgdrtgrtg();
}
}Thanks for the help.