MarkupContainer's children field is declared as an Object and can refer to
a ChildList - which is a List, hopefully (until it's genericised) of Components, an Object[] - again, hopefully of Components, a Component - ie a single child, or, even a ComponentSourceEntry - a bare-bones representation of only the "essentials" of a Component from which it can be reconstructed. I assume MarkupContainer's implementation was refactored (_from_ something much more straight-forward) as an optimisation, in particular related to serialisation, with the argument probably along the lines of: it is common for a MarkupContainer to have just a single child, so we don't want the luggage of a List in those cases etc ... All this can make MarkupContainer pretty fragile, easy to accidentally break. If the optimisation argument is really strong enough (I expect it must have been at the time and may still be), at the very least, all the messy operations on "children" could be encapsulated in a class (perhaps called FunkyChildren, possibly as an inner class if it necessarily needs access to its owning MarkupContainer instance's guts and is never used outside this context) that exposes only friendly methods like set(int index,Component child) and remove(Component child) etc ... Apart from simplifying MarkupContainer, the above design would also have the benefit of making it possible to address the problem in hand (with the illegal runtime array cast), mend what's broken and test this funky, edge-case(?) behaviour without having to interfere with MarkupContainer. And, if there's a simpler/better/more efficient FunkyChildren possible for 1.5 just plug in the new implementation. Importantly, as this an internal change (internal to MarkupContainer), there will be no API break (neither within Wicket nor in the public API). Regards - Cemal http://www.jWeekend.co.uk http://jWeekend.co.uk Matej Knopp-2 wrote: > > this > > sorted = Arrays.asList((Component[])children); > > doesn't look right. I think it should have been (Object[])children > although a type check would be appropriate. > > -Matej > > On Fri, Nov 28, 2008 at 7:30 PM, jWeekend <[EMAIL PROTECTED]> > wrote: >> >> Not quite. >> String[] bO = (String[])(new Object[]{"yes","we","can"}); >> compiles but fails at run time. >> >> Regards - Cemal >> http://www.jWeekend.co.uk http://jWeekend.co.uk >> >> >> >> Valentine2008 wrote: >>> >>> It will bring the compilation error when trying to cast arrays in Java. >>> >>> So you mean it is a bug in Wicket? >>> >>> >>> Timo Rantalaiho wrote: >>>> >>>> On Thu, 27 Nov 2008, Valentine2008 wrote: >>>>> java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to >>>>> [Lorg.apache >>>>> .wicket.Component; >>>>> at >>>>> org.apache.wicket.MarkupContainer.iterator(MarkupContainer.java:478) >>>>> ......... >>>>> >>>>> The code on line 478 of MarkupContainer.java is: >>>>> sorted = Arrays.asList((Component[])children); >>>>> >>>>> Is it a bug of Wicket? >>>> >>>> No, I think it's a limitation of Java. You cannnot cast >>>> arrays. >>>> >>>> Best wishes, >>>> Timo >>>> >>>> -- >>>> Timo Rantalaiho >>>> Reaktor Innovations Oy <URL: http://www.ri.fi/ > >>>> >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: [EMAIL PROTECTED] >>>> For additional commands, e-mail: [EMAIL PROTECTED] >>>> >>>> >>>> >>> >>> >> >> -- >> View this message in context: >> http://www.nabble.com/Bug-of-Wicket-1.3.4-when-iterate-the-form-using-iterator%28Comparator%29--tp20723903p20738179.html >> Sent from the Wicket - User mailing list archive at Nabble.com. >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [EMAIL PROTECTED] >> For additional commands, e-mail: [EMAIL PROTECTED] >> >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > -- View this message in context: http://www.nabble.com/Bug-of-Wicket-1.3.4-when-iterate-the-form-using-iterator%28Comparator%29--tp20723903p20764684.html Sent from the Wicket - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
