Re: can I use fetch spec to filter an array?
Re: can I use fetch spec to filter an array?
- Subject: Re: can I use fetch spec to filter an array?
- From: Chuck Hill <email@hidden>
- Date: Thu, 01 Jan 2004 11:16:44 -0800
Hi Denis,
At 03:03 PM 01/01/2004 +1300, Denis Stanton wrote:
>I never understood how returning null created the page. It now seems
>to me that returning null amounts to "keep looking for something to do,
>and if you don't find it just repeat this page"
>
Yes, that is pretty much exactly it. I have no idea why 'null' was
documented as the preferred return value. I think the code that does this
is roughly
while (there are more elements and resultPage == null) {
nextPage = elements.nextElement().invokeAction(aRequest, aContext);
}
If (nextPage == null) {
nextPage = aContext().page();
}
Chuck
[discussing how WO finds the component that is the target of an action
binding]
>>> This seems like a very bad thing. I click the submit button in a
>>> little query form at the top of the page and WO has to re-expand the
>>> whole rest of the page before it can figure out that the submit button
>>> was clicked?
>>>
>> No, just until it finds what was clicked. This is why it is a bad
>> idea to return null from action methods: WO keeps looking for the
>> component responsible for the action. With the query form at the top
>> it should stop fairly quickly. If you put the form inside a table or
>> at the bottom of the page it can be a different story.
>
>That's odd. The submit button is in a form at the top of the page.
>After that there is a repetition that works through the agent list, but
>there are no further active elements. Repeated (and pointless) calls
>to setAgent are made before it finds and executes the action method
>bound to the submit button
>
>>> This page has no links from inside the repetition. There
>>> seems to be no reason to re-expand the page.
>>>
>> It is just doing a tree traversal until it finds the correct action.
>> If your action method has
>> return null;
>> that is the cause. Do this instead:
>> return context().page();
>
>OK, that worked. Why is return null the standard (default) response?
>I never understood how returning null created the page. It now seems
>to me that returning null amounts to "keep looking for something to do,
>and if you don't find it just repeat this page"
>
>Denis Stanton
>email@hidden
>Home: +64 9 533 0391
>mobile: +64 21 1433622
>
>
--
Chuck Hill email@hidden
Global Village Consulting Inc. http://www.global-village.net
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