Re: any recommendations?

From:

Brandon McCombs <none@none.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 06 Feb 2007 10:03:34 -0500

Message-ID:

<45c89857$0$4928$4c368faf@roadrunner.com>

Michael Rauscher wrote:

Brandon McCombs schrieb:

Nigel Wade wrote:

Brandon McCombs wrote:

The method I call for deleting a selected item from the JList is the
following (model is the instance of BrowserModel):

private void list_deleteObj() {
      int idx = dirList.getSelectedIndex();
      String dn = LDAPMgr.ldapUtility.getDN(
              model.getListModel().getElementAt(idx) );
      int ans = JOptionPane.showConfirmDialog(this,
              "Confirm delete for:\n" + dn + "\n",
              "Delete Object",JOptionPane.YES_NO_OPTION,
              JOptionPane.PLAIN_MESSAGE);
      if (ans == 1)
              return;
      String msg = null;
      msg = LDAPMgr.ldapUtility.deleteEntry(
              model.getListModel().getElementAt(idx));
      /* if successful */
      if (msg == null) {
              model.getListModel().remove(idx);
              /* reload the subtree and list to show deletion */
              refresh();
      }
}

What thread is the above method being executed on? If it's not the
EDT you have
a problem there, you are modifying the JList in a thread other than
the EDT.

The error is telling you that when the EDT came to draw a JList it
tried to
access element 1 and that element didn't exist in the the
DefaultListModel's
Vector at the time. That would imply a synchronization error, the
Vector is in
the process of being modified whilst it's being drawn (the JList and
DefaultTreeModel have a different idea of how many elements there
are), and I
don't see how that can happen unless it's being modified from another
thread -
even the EDT can only do one thing at a time...

Maybe I did this wrong but in the place in my code where I call the
method above I put the following:

SwingUtilities.invokeLater(new Runnable() {
public void run() {
list_deleteObj(); }
});

And I still get the exception generated so what am I missing?

Look out for other threads. What does e. g. AsynchSearch do?

It retrieves the current state of what the list should contain by
contacting an LDAP server. It then alerts the GUI the results are ready
by calling the GUI's updateGUI() method by I do that on the EDT like
above so it should be okay.

What I ended up doing that seems to work so far is I put the body of the
method prepareGUI() inside of the SwingUtilities.invokeLater() call.
The prepareGUI() is called by asyncSearch to prepare the GUI before the
newest results are loaded. prepareGUI() is actually what deletes the
rest of the items in the listmodel so that I don't get duplicate entries
when it is updated. I've been testing that and haven't received the
exception, yet.