Hi,
On Sun, Oct 21, 2012 at 11:54 AM, Ernesto Reinaldo Barreiro
<reier...@gmail.com> wrote:
> Hi,
>
> On Sun, Oct 21, 2012 at 10:57 AM, Gonzalo Aguilar Delgado <
> gagui...@aguilardelgado.com> wrote:
>
>> Hello Ernesto,
>>
>> I sometimes get confused myself. ;-) I think that I don't understand
>> well this piece of code:
>>
>> @Override
>> public final void onRequest()
>> {
>> WebApplication app =
>> (WebApplication)getComponent().getApplication();
>> AjaxRequestTarget target =
>> app.newAjaxRequestTarget(getComponent().getPage());
>>
>> RequestCycle requestCycle = RequestCycle.get();
>> requestCycle.scheduleRequestHandlerAfterCurrent(target);
>>
>> respond(target);
>> }
>>
>>
>
> AJAX requests are handled int two steps (please Martin and/or other core
> developers correct me if I'm saying something wrong;-). First is is
Actually everything is in two steps, not only Ajax.
The first step is the ACTION phase and the second is the RENDER phase.
> executed ListenerInterfaceRequestHandler (which delegates
> on IBehaviorListener#onRequest). So, there you a new request handler is
> scheduled after current, so once wicket finishes processing current request
> handler it will start processing the new scheduled request handler (that
> will produce the AJAX output). This technique is used in many places on the
> framework, Eg. DownloadLink#click()
>
> public void onClick()
> {
> final File file = getModelObject();
> if (file == null)
> {
> throw new IllegalStateException(getClass().getName() +
> " failed to retrieve a File object from model");
> }
>
> String fileName = fileNameModel != null ? fileNameModel.getObject() : null;
> if (Strings.isEmpty(fileName))
> {
> fileName = file.getName();
> }
>
> fileName = UrlEncoder.QUERY_INSTANCE.encode(fileName,
> getRequest().getCharset());
>
> IResourceStream resourceStream = new FileResourceStream(
> new org.apache.wicket.util.file.File(file));
> getRequestCycle().scheduleRequestHandlerAfterCurrent(
> new ResourceStreamRequestHandler(resourceStream)
> {
> @Override
> public void respond(IRequestCycle requestCycle)
> {
> super.respond(requestCycle);
>
> if (deleteAfter)
> {
> Files.remove(file);
> }
> }
> }.setFileName(fileName)
> .setContentDisposition(ContentDisposition.ATTACHMENT)
> .setCacheDuration(cacheDuration));
> }
>
>
>
>> Because the AjaxRequestTarget is really a handler like
>> TextRequestHandler but I don't know the
>> call machanism.
>>
>
> Look at the code RequestCycle#processRequestAndDetach.... and the calls it
> makes.
>
>>
>> What does the requestCycle.scheduleRequestHandlerAfterCurrent(target);
>> here and when used
>> with a TextRequestHandler. What's the difference?
>>
>
> There is no difference, you tell wicket that after current handler it
> should "discard" the results and execute next handler. In your case instead
> of returning an AJAX response return some text (JSON) response.
>
>
>> Is there any way where this mechanism is explained?
>>
>>
> I don't know if Martin or other core developers explain this somewhere?
>
RequestCycle's javadoc contains a bit but it can definitely be extended.
Another docu that can explain this is
https://cwiki.apache.org/confluence/display/WICKET/RequestCycle+in+Wicket+1.5.
I'll try to extend both soon.
>
>> Thank you a lot!
>>
>>
> You are welcome:-)
>
> --
> Regards - Ernesto Reinaldo Barreiro
> Antilia Soft
> http://antiliasoft.com
--
Martin Grigorov
jWeekend
Training, Consulting, Development
http://jWeekend.com
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