Name: skT88420 Date: 10/13/99


removeAll() in java.awt.Choice actually loops through removing
items 1 at a time. This is very slow if you have a lot of items
(500+). In 1.2.2 we overrode removeAll() in a subclass
of Choice to speed things up such that it takes about 40% of
the time to do the same thing:


/*
 * hack to speed up removeAll()
 */
public void removeAll() {
   removeNotify(); // kills the peer
   super.removeAll(); // call the real removeAll()

   try {
      addNotify(); // adds back the peer
   } catch (Exception e) {
      // null pointer exception if we never
      // added this Choice to a container
   }
}

This hack speeds up the removal of items from a Choice because
you no longer have a peer slowing things down. It works fine
in 1.2.2 and 1.3beta. However, when this code
ran with 1.3 RA ... it "seemed" to work but when you pass the
mouse over the Choice or try to click on it you get this:


Exception occurred during event dispatching:
java.lang.NullPointerException: null pData
        at sun.awt.windows.WInputMethod.handleNativeIMEEvent(Native Method)
        at sun.awt.windows.WInputMethod.dispatchEvent(Unknown Source)
        at sun.awt.im.InputContext.dispatchEvent(Unknown Source)
        at sun.awt.im.InputMethodContext.dispatchEvent(Unknown Source)
        at java.awt.Component.dispatchEventImpl(Unknown Source)
        at java.awt.Component.dispatchEvent(Unknown Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)

It turns out it has to do with the focus. If the Choice had focus
when you called removeAll(), you get the exceptions whenever
the mouse tries to send events to the component. Simply
mouse-clicking on any other component such that it gains focus
will stop the exceptions and you can now click on the Choice.
If the Choice did not have focus, you can call removeAll() and
it works fine.

I know calling removeNotify() is a bad thing but removing our
hack more than doubles the time it takes to clear a Choice!! That
is why I am submiting this as a feature request instead of a bug.
Hoping it can be fixed at the root so I don't need a hack.
(Review ID: 96519)
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