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From "Frank W. Zammetti" <fzli...@omnytex.com>
Subject Re: Struts and AJAX
Date Mon, 03 Jul 2006 18:01:02 GMT
I'm a big fan of DWR as well, it's a very worthy alternative.

But, I don't mind a little self-promotion, so... how does this strike 
you? ...

<ajaxConfig>
   <group ajaxRef="MyForm" form="compose_mail_form">
     <element ajaxRef="SubmitButton">
       <requestHandler type="std:QueryString" target="/process_new_mail.do">
       <parameter>to=to</parameter>
       <responseHandler" type="std:Alerter">
       <parameter />
     </element>
   </group>
</ajaxConfig>

Then, in your JSP:

<html:form styleId="compose_mail_form" method="post"
action="process_new_mail" enctype="multipart/form-data" focus="to">
<label for='to' <logic:messagesPresent
property="to">class='error'</logic:messagesPresent>>To:</label>
<html:text property="to" styleClass="text" style="width: 25%;" />
<br class="clear" />
  ...
//more form elements
...
<a href="#">SUBMIT</a><ajax:event ajaxRef="MyForm/SubmitButton" />
</html:form>
<ajax:enable />

This would result in some Action, mapped to process_new_mail.do being 
executed, and you would get a single parameter submitted, "to", using 
the value of the form field "to".  The response from the server, 
whatever it is, would be displayed via alert().

This is what AjaxParts Taglib (APT) offers... you define an event in a 
config file, some user-initiated (usually) event that fires an AJAX 
request.  For each event, you define a request handler, which forms the 
request to the server... there are a number of "standard" handlers, for 
instance, if you want to construct XML from your form, that's standard. 
  You also define one (or more) response handlers, which is something 
that happens when the response comes back.  Again, there are a number of 
standard handlers, like Alerter... there is also things like InnerHTML 
(populate a page element by updating innerHTML), stdXSLT (transform XML 
response via XSLT on client), and much more.

Note that you didn't have to right ANY Javascript whatsoever!  And the 
changes to your JSP amounts to adding an <ajax:event> tag to any element 
that will fire an AJAX event, and the <ajax:enable> tag at the end (plus 
the taglib declaration of course).  Changing the AJAX functionality is 
as easy as modifying the config file, you wouldn't need to touch your 
JSP again!  And, should you need to do more advanced things that the 
standard handlers don't cover (they should do the job probably 80% of 
the time or better though), there is a pretty simple mechanism for 
writing your own custom handlers, which you can then use just like the 
standard handlers.

If the no coding approach sounds good, check it out further:

http://javawebparts.sourceforge.net/

I suggest clicking the Javadocs link and going to the first package 
listed, javawebparts.ajaxparts.taglib... all the details can be found 
there... then, download JWP and check out the sample app for all sorts 
of examples of APT usage.

Shill time over :)

Frank

draegoon Z wrote:
> Hey,
> 
> I use DWR + dojo to use AJAX with struts:
> 
>     http://getahead.ltd.uk/dwr/
> 
>     http://dojotoolkit.com/
> 
> Although dojo has some flashy widgets and stuff, its power is the 
> dojo.io.bind() function:
> 
>     http://dojotoolkit.org/docs/intro_to_dojo_io.html
> 
> 
> 
> Here is an example of using Struts Actions with bind():
> 
> 
> <html:form styleId="compose_mail_form" method="post" 
> action="process_new_mail" enctype="multipart/form-data" focus="to">
> 
> 
> <label for='to' <logic:messagesPresent 
> property="to">class='error'</logic:messagesPresent>>To:</label>
> <html:text property="to" styleClass="text" style="width: 25%;" />
> <br class="clear" />
> 
> ...
> //more form elements
> ...
> 
> <a href="#" onclick="submitNewMail();">SUBMIT</a>
> </html:form>
> 
> NOTE: form has been given a 'styleId' and using <logic:messagesPresent> 
> to display errors in form
> 
> 
> function submitNewMail(){
> 
>        //validateNewMail(form);
> 
>        var bindArgs = {
>        url: "<html:rewrite action="process_new_mail" />",
>        error: function(type, data, evt){
>            alert("An error occurred submitting new mail: " + data);
>        },
>        load: function(type, data, evt){
> 
>            DWRUtil.setValue("social_mail_right_con", data);    /* 
> setValue doesn't execute javascript! */
>            
> document.getElementById('social_popup_layer_container').innerHTML=document.getElementById('ajax_hidden_helper').innerHTML;

> 
>            popup('social_popup_layer_container',true);
> 
>        },
>        mimetype: "text/html",
>        formNode: document.getElementById("compose_mail_form")
>        };
> 
>        dojo.io.bind(bindArgs);
>    }
> 
> 
> NOTE:
> 
> 1) the use of <html:rewrite /> for the 'url'
> 
> 2) formNode is the 'styleId' of your <html:form />
> 
> 3) the stuff you see in the load function is application specific. It is 
> how I display <html:errors />
>    and <html:messages /> in a backwards-compatible manner for AJAX. I 
> basically force
>    the reloading of a JSP (tile) that has the code: <html:errors /> and 
> relevant logic.
> 
> 
> Ok, now for the good stuff:
> 
> 1) Yes, your ActionForm will work as usual. If it is invalid, errors are 
> displayed. If it validates, it goes
>    on to the Action.
> 
> 2) The action MUST RETURN "NULL", otherwise the page will reload to your 
> <forward>
> 
> 3) You write your output to the response object in your action. Remember 
> when it was just servlets?
> 
> public ActionForward execute(ActionMapping mapping, ActionForm form, 
> HttpServletRequest request, HttpServletResponse response) throws 
> IOException, ServletException {
> 
>     //Make ActionMessages for business logic errors...
>     ActionMessages messages = new ActionMessages();
>     HttpSession session = request.getSession();
>     MyForm f = (MyForm)form;
> 
>     response.setContentType("text/html");
>     PrintWriter out = response.getWriter();
> 
> 
>     out.print("ACTION_SUCCESS:Message Sent!");
>     out.close();
> 
> 
>     //return(mapping.findForward("success"));    NOT AJAX WAY!
> 
>     return(null);
> }
> 
> 
> There are many ways to handle the repsonse stuff with AJAX + STRUTS. Use 
> your imagination.
> 
> In this instance I just have a javascript function parse the output. You 
> could return HTML and use
> innerHTML(). You could parse a string like: "FORWARD:my_action_name".
> You could have: "JAVASCRIPT-FUNCTION:handleSuccess()".
> 
> I often use dojo.io.bind() in conjunction with DWR.setValue():
> 
>     http://getahead.ltd.uk/dwr/browser/util/setvalue
> 
> or using DWR to forward to a JSP:
> 
>     http://getahead.ltd.uk/dwr/examples/text
> 
> 
> 
> Bottom line is that javascript will handle the forwarding instead of you 
> struts config.
> If some has a way to do it with the config, I'd love to hear from you.
> 
> 
> BTW - I took the time to write this because after all the reading and 
> searching I did,
> I still didn't have a clue how to use all this stuff together. I hope 
> this helps everyone.
> 
> -Joe
> 
> 
> 
> 
> ----------------------------------------------------------------------------------- 
> 
> 
> WEB DESIGN BY DRAEGOONZ
> 
> Joseph "DraegoonZ" McGranaghan
> 
> http://www.draegoonZ.com
> 
> 603-620-0854
> 
> draegoonZ@draegoonZ.com
> 
> 
> 
> 
>> From: chamal desilva <chamalsl@yahoo.com>
>> Reply-To: "Struts Users Mailing List" <user@struts.apache.org>
>> To: user@struts.apache.org
>> Subject: Struts and AJAX
>> Date: Sun, 2 Jul 2006 20:57:52 -0700 (PDT)
>>
>> Hi,
>>
>> Can I use struts with AJAX. Does struts has classes
>> and tags for AJAX or do I have write my own code.
>>
>> Thanking You,
>> Chamal.
>>
>> __________________________________________________
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> 
> 
> 
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> 
> 
> 

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
AIM: fzammetti
Yahoo: fzammetti
MSN: fzammetti@hotmail.com
Java Web Parts -
http://javawebparts.sourceforge.net
Supplying the wheel, so you don't have to reinvent it!

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