DefaultListModel problem
Warpig
I am having a problem with the DefaultListModel of the JList. I have
declared the as below:
private JList allGroupsList;
private JList activeGroupsList;
private DefaultListModel allGroupsModel;
private DefaultListModel activeGroupsModel;
allGroupsModel = new DefaultListModel();
allGroupsList = new JList(allGroupsModel);
activeGroupsModel = new DefaultListModel();
activeGroupsList = new JList(activeGroupsModel);
I then have a button that when clicked, reads in a file and places the
file's contents into the allGroupsModel object. The code for this is:
try
{
File f = new File("groups.txt");
BufferedReader br = new BufferedReader(new FileReader(f));
StringTokenizer first = new StringTokenizer(br.readLine());
String line = first.nextToken();
int i = 1;
while(!line.equals(""))
{
allGroupsModel.addElement(line);
StringTokenizer st = new StringTokenizer(br.readLine());
line = st.nextToken();
}
br.close();
}
catch(IOException e)
{
System.err.println(e.toString());
}
The "groups.txt" file has approximately 23,000 lines in it and when
loaded, the list contains them all, however, I get the following exception:
Exception occurred during event dispatching:
java.lang.NullPointerException
at java.util.StringTokenizer.<init>(StringTokenizer.java:122)
at java.util.StringTokenizer.<init>(StringTokenizer.java:152)
at GroupDialog.actionPerformed(GroupDialog.java:262)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1450)
at
javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1504)
at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:378)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:250)
at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:216)
at java.awt.Component.processMouseEvent(Component.java:3715)
at java.awt.Component.processEvent(Component.java:3544)
at java.awt.Container.processEvent(Container.java:1164)
at java.awt.Component.dispatchEventImpl(Component.java:2593)
at java.awt.Container.dispatchEventImpl(Container.java:1213)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2216)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
at java.awt.Container.dispatchEventImpl(Container.java:1200)
at java.awt.Window.dispatchEventImpl(Window.java:926)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:339)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)
at java.awt.Dialog.show(Dialog.java:380)
at PicAgentFrame.actionPerformed(PicAgentFrame.java:260)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1450)
at
javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1504)
at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:378)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:250)
at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:216)
at java.awt.Component.processMouseEvent(Component.java:3715)
at java.awt.Component.processEvent(Component.java:3544)
at java.awt.Container.processEvent(Container.java:1164)
at java.awt.Component.dispatchEventImpl(Component.java:2593)
at java.awt.Container.dispatchEventImpl(Container.java:1213)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2216)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
at java.awt.Container.dispatchEventImpl(Container.java:1200)
at java.awt.Window.dispatchEventImpl(Window.java:926)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:339)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:85)
The second JList (activeGroupsModel) I have contains the selected
components of the allGroupsModel when the add button has been clicked.
Moving the selected componenets from one list to the other works
fine, however, if I try to use the remove button which places selected
components of the activeGroupsModel back into the allGroupsModel, I get
an exception and not all selected components are removed. The code for
this is:
public void addToActiveGroups(String groupName)
{
activeGroupsModel.addElement(groupName);
}
public void addToAllGroups(String groupName)
{
allGroupsModel.addElement(groupName);
}
//this section is within the actionPerformed method
else if(source == addButton)
{
/*
* Add the selected elements from the list of the left
* to the list on the right and then remove the seelcted
* elements from the list on the left
*/
int[] selected = allGroupsList.getSelectedIndices();
System.out.println("ADD : int[] size is " + selected.length);
for(int i = 0; i < selected.length; i++)
{
addToActiveGroups((String)allGroupsModel.elementAt(selected[i]));
allGroupsModel.removeElementAt(selected[i]);
}
}
else if(source == removeButton)
{
/*
* Remove the selected elements from the list on the right
* and replace them into the list on the left. I'll just
* addElement for now, but ideally, I'll insert it into the
* correct position of the left hand sided list as that will
* be sorted
*/
int[] selected = activeGroupsList.getSelectedIndices();
System.out.println("REMOVE: int[] size is " + selected.length);
for(int i = 0; i < selected.length; i++)
{
addToAllGroups((String)activeGroupsModel.elementAt(selected[i]));
activeGroupsModel.removeElementAt(selected[i]);
}
}
The int arrays are reported as the correct size, but not all of the
slected elements are removed. The Exception I get is:
//the next to lines are not part of the exception...
ADD : int[] size is 4
REMOVE: int[] size is 4
Exception occurred during event dispatching:
java.lang.ArrayIndexOutOfBoundsException: 2 >= 2
at java.util.Vector.elementAt(Vector.java:417)
at javax.swing.DefaultListModel.elementAt(DefaultListModel.java:248)
at GroupDialog.actionPerformed(GroupDialog.java:311)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1450)
at
javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1504)
at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:378)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:250)
at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:216)
at java.awt.Component.processMouseEvent(Component.java:3715)
at java.awt.Component.processEvent(Component.java:3544)
at java.awt.Container.processEvent(Container.java:1164)
at java.awt.Component.dispatchEventImpl(Component.java:2593)
at java.awt.Container.dispatchEventImpl(Container.java:1213)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2216)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
at java.awt.Container.dispatchEventImpl(Container.java:1200)
at java.awt.Window.dispatchEventImpl(Window.java:926)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:339)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)
at java.awt.Dialog.show(Dialog.java:380)
at PicAgentFrame.actionPerformed(PicAgentFrame.java:260)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1450)
at
javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1504)
at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:378)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:250)
at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:216)
at java.awt.Component.processMouseEvent(Component.java:3715)
at java.awt.Component.processEvent(Component.java:3544)
at java.awt.Container.processEvent(Container.java:1164)
at java.awt.Component.dispatchEventImpl(Component.java:2593)
at java.awt.Container.dispatchEventImpl(Container.java:1213)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2216)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)
at java.awt.Container.dispatchEventImpl(Container.java:1200)
at java.awt.Window.dispatchEventImpl(Window.java:926)
at java.awt.Component.dispatchEvent(Component.java:2497)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:339)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:85)
I am using JDK1.3.1 on Linux if this is of any help.
I know there is a lot of code and exception stacktrace here, but I was
hoping that someone could shed some light on this - I haven't had much luck!
Thanks in advance!
Regards,
Leigh
Todd Neumiller
end of the file.
Also the BufferedReader is going to strip any eol characters,
so it is hard to tell why you are using a stringtokenizer
when you only get the 1st token of each line?
If each line is intended for one row in your List then you
do not need the stringtokenizer
I would guess (with out seeing the text file contents)
try
{
File f = new File("groups.txt");
BufferedReader br = new BufferedReader(new FileReader(f));
String line = br.readLine();
while(line != null)
{
allGroupsModel.addElement(line);
int i = 1;
line = br.readLine();
}
br.close();
}
catch(IOException e)
{
System.err.println(e.toString());