"Craig R. McClanahan" wrote:
>
> Bugzilla bug report #706 reports that you will get a JSP page exception
> when you try to iterate over collection that contains null values. This
> is caused by the fact that the JSP page context refuses to allow null
> attributes. The bug report suggests one alternative (although the
> proposed implementation has problems), but I would like to solicit
> suggestions and thoughts on what the correct behavior should be.
>
> Here are the alternatives that I can think of:
>
> (1) No change -- document a restriction in the usage notes
> on the <logic:iterate> tag.
>
> (2) Silently skip this element of the iteration, with no notice
> to the surrounding page. The total number of times through
> the loop, from the perspective of the page, will be less than
> the size of the underlying collection.
>
> (3) Do not skip this element, but don't add it to the page context
> either. The page can then use <logic:notPresent> to test for
> whether the item is actually there or not.
>
> (4) Do not skip this element, but insert a reference to a dummy
> object instead of the null. This is likely to cause class cast
> exceptions, and is unlikely to be practical when the iteration
> explicitly includes a "type" attribute.
>
> (5) Other alternatives I have not thought of?
(5) Add an attribute(s) on the iterate tag that allows the user to
decide between (1), (2) and (3). Defaulting to (1).
>
> All of the listed alternatives have their problems, but I am currently
> leaning towards (1). Comments? Suggestions?
>
> Craig McClanahan
