Thanks for the overview Frank. I'm using struts 2 and will lookup how to
writeup AJAX requests to get this done.
Thanks a bunch,
Session
> Is this Struts1 or Struts2? That will (potentially) change the mechanics
> a little, but in theory, sure, it's easy to do. Assume Struts1 for a
> moment...
>
> 1. User triggers event on the page that does the delete. This causes a
> Javascript function to be executed. 2. That function makes an AJAX
> request, using your favorite library. 3. Action is invoked (AJAX just
> requests a URL after all, which is what a Struts action mapping is) and
> does its work. 4. Action forwards to a JSP as is typical. This JSP can be
> something as simple as this:
>
> <% if (request.getAttribute("deleted") != null) { %>
> <%=request.getAttribute("nodeID")%> <% } else { %> NOT DELETED <% } %>
>
> Assuming the action put the "deleted" attribute in request if the delete
> was accomplished, as well as the ID of the ndoe that was deleted, that's
> all there is to it.
>
> 5. The response is returned to the client, and being an AJAX request, some
> Javascript function that you specified at the time the call was made, the
> AJAX callback function, is executed. Passed to it will be the response
> from the server. So, you simply do a quick check to see which string got
> returned, and if its != "NOT DELETED", call whatever delete method likely
> exists for the tree widget your using (most provide this), passing it the
> response from the server, which is in fact the ID of the node to delete.
> No need to rebuild the tree, no need to re-render the page, no need to
> return an updated set of data, just delete the one node you need to.
>
> That's all there is to it. Now, you don't even need the JSP if you don't
> want to have it, you can write the same response out from the Action, but
> using a JSP, even for something as trivial as this, tends to be more
> flexible and easier to toy with. AJAX always works this way, basically,
> so if your talking Struts2 you may do some things slightly different
> because there's some built-in AJAX support that might hide some of this
> from you and make it easier, but basically it's the same underlying flow.
>
> Frank
>
> -- Frank W. Zammetti Founder and Chief Software Architect Omnytex
> Technologies http://www.omnytex.com AIM/Yahoo: fzammetti MSN:
> [EMAIL PROTECTED] Author of "Practical Ajax Projects With Java
> Technology" (2006, Apress, ISBN 1-59059-695-1) and "JavaScript, DOM
> Scripting and Ajax Projects" (2007, Apress, ISBN 1-59059-816-4) Java Web
> Parts - http://javawebparts.sourceforge.net Supplying the wheel, so you
> don't have to reinvent it!
>
> Session A Mwamufiya wrote:
>> The jsp page sends a delete request to the struts action that
>> determines whether or not the object associated with the node can be
>> deleted from the database. The struts action removes the object from
>> the database if all is well, and at this point, I would like to have
>> the struts action notify the jsp that it can remove the node from the
>> tree. Is there a way to set it up so that the jsp page gets a return
>> value from the action and javascript within the jsp page removes the
>> node accordingly?
>>
>> Thanks, Session
>>
>>
>>> 3. Generate JavaScript in the Ajax result that removes the node (and
>>> re-renders the tree if necessary; I don't know how all that works)
>>> and execute it.
>>>
>>> --- Chris Pratt <[EMAIL PROTECTED]> wrote:
>>>
>>>> You can use the Rhino JavaScript interpreter to execute JavaScript
>>>> from Java, but I don't think that's actually what you are looking
>>>> for.
>>>>
>>>> It sounds like you are asking "How to I run some JavaScript in the
>>>> client's browser when something changes on the server?" And the
>>>> short answer is, you can't. At least not directly.
>>>>
>>>> Remember, the web uses a Request/Response model where the Browser
>>>> makes a request and the server returns a response, so there is no
>>>> simple way for the server to initiate something happening in the
>>>> browser.
>>>>
>>>> Two options I can see are:
>>>>
>>>> 1. Have the browser make an AJAX request and the server can return
>>>> the new DOM tree without the removed node
>>>>
>>>> 2. Have the browser resubmit the request and the new page can be
>>>> built without the removed node.
>>>>
>>>> (*Chris*)
>>>>
>>>> On 9/6/07, Session A Mwamufiya <[EMAIL PROTECTED]> wrote:
>>>>> Hi,
>>>>>
>>>>> Does anyone have an example of how to call a
>>>> javascript function from a java class? I want to call a javascript
>>>> function that removes a node from a tree after a java class
>>>> removed it from the database.
>>>>> Thanks, Session
>>>>>
>>>>>
>>>>>
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