Re: final variables as parameters due to action listeners

From:
Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 30 Apr 2006 18:23:02 -0700
Message-ID:
<Ypd5g.13292$oz1.9708@newsfe06.phx>
timasmith@hotmail.com wrote:

Hi,

I have the following code which complains with 'Cannot refer to a
non-final variable controlPanel inside an inner class defined in a
different method':

private void addPanelListeners(PanelAddRemove controlPanel) {
   controlPanel.getPrintButton().setText("Move up");
   controlPanel.getPreviewButton().setText("Move down");
   controlPanel.getPrintButton().addActionListener(new
MenuActionListener(frame) {
      public void actionExecuted(ActionEvent e) throws Exception {
        int position = controlPanel.getSelectedIndex();
      }
   });
}

If however I change the parameter to be final

private void addPanelListeners(final PanelAddRemove controlPanel) {

it no longer complains. I must confess I used to create a private
variable in the class as a work around which worked but was ugly. Now
are there any detrimental side effects to making the object final - I
assume it means dont point controlPanel to another value - but
otherwise it is fine?

thanks

Aron


That doesn't work though does it?

--

Knute Johnson
email s/nospam/knute/

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