RichFaces 4: FileUpload Clear Event

[lessonz]

So, I've tried catching the clear event from the "Clear All" button in a FileUpload component with no luck.

<a4j:ajax event="clear" execute="@none" render="testPanel" />

Any suggestions as to how to catch this event? Thanks.

[ilya_shaikovsky]

actually that looks like a bug http://docs.jboss.org/richfaces/latest_4_0_X/vdldoc/ do not contains such handler. so please add jira issue on that.

[bcn]

Yeah, a clear listener is urgently necessary!

Both for the clear all as for individual clear actions.

Is the jira issue created already?

Thanks,

Ulrich

[lessonz]

https://issues.jboss.org/browse/RF-10952

[bleathem]

Issue RF-10952 has been resolved.  It will be available when RichFaces 4.1.0.M3 has been released. (soon!)

[bcn]

Hello,

I tried the clear handler like this:

<rich:fileUpload>

<a4j:ajax event="clear" listener="#{bean.clearUpload}"  />

</rich:fileUpload>

public void clearUpload() {...}

The bean method is called when Clear All is clicked as well as when an individual item is removed.

But how can I distinguish these two cases and, in the latter, how can I find out in the bean method which item was removed?

Thanks

[bleathem]

Your listener might be able to inspect the list of items cleared from the AjaxBehaviorEvent parameter.

[bcn]

Okay, the bean method can be

public void clearUpload(AjaxBehaviorEvent event) {...}

but I am unable to find out the deleted item from the event object.

I can get UIFileUpload from event.getSource(), but still no idea where to get the deleted file from.

Thanks

[bcn]

I think it is impossible to determine which file was cleared. The parameter of the listener should be a FileUploadEvent, otherwise there is no reference to the file. The component has no "var" attribute to bind a bean variable to. One could define a f:param on the a4j:ajax tag, but to what could its value be set? I am stuck.

[bleathem]

Hmm, there are few other events you can tap into, but I'm curious, what's your use case for knowing which file has been cleared?

[bcn]

The user uploads several files, then clears only one of them. So I have to remove only that item from my list of uploaded items in the bean, not all of them.

[bleathem]

Having dug into this, it is apparent there are a number of problems with the clear handler of the file upload component.  I've got some working code showing how you can remove the uploaded files from your backing bean, but I had to create and resolve RF-11744 to do so.  You'll need a recent 4.1.0-SNAPSHOT to try this out, or wait for the next release (CR2).  I've included code snippets here, but you can see the code in context in the dev-examples.

Consider the autocomplete tag: (From: autocomplete.xhtml)

        <rich:fileUpload fileUploadListener="#{fileUploadBean.listener}" onclear="onclear(event)" ... >
            <a4j:ajax event="uploadcomplete" execute="@none" render="info" />
        </rich:fileUpload>

The onclear handler is a javascript method that digs the file list out of the javascript event:

            var onclear = function (event) {
                var data = event.rf.data;
                for (var i in data) {
                    var item = data[i];
                    removeFile(item.name);
                }

Then you'll need a <a4j:jsFunction> for the onclear handler to call into, and initiate the ajax call:

        <a4j:jsFunction name="removeFile" render="info" action="#{fileUploadBean.clearFile}">
            <a4j:param name="clearedFile" assignTo="#{fileUploadBean.clearedFile}" />
        </a4j:jsFunction>

I'm pretty sure this can be done with a RichFaces javascript API call, but I couldn't find it off hand.

You'll then have a backing bean (see: FileUploadBean.java) method "fileUploadBean.clearFile" that will be called once for each file removed, where the file to remove is stored in the backing bean property "clearedFile".

This is functional, but gross - I consider it a workaround.  Would you please file a jira asking for a JSF behaviour to be added to the fileuplaod component, to make it easier to write onclear listeners?  We can address that in the 4.2 release timeframe.

Brian

[bcn]

Thanks for your help!

JIRA entry:

https://issues.jboss.org/browse/RF-11746