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Posted to dev@cocoon.apache.org by Stefan Pietschmann <sp...@inf.tu-dresden.de> on 2005/01/04 09:25:28 UTC

getElementById in request does not work

Hi there,

I'm writing my custom action, and this is my problem with it:

I fetch a parameter from the request (which is sent with a form). It
contains an small rdf snippet. I thought I'd be able to read it out with
getelementbyid, but it doesn't work. The request parameter looks like this:

<RDF>
  <Description id="Profile">
    <component>
      <Description id="UserInteraction">.</Description>
    </component>
    <component>
      <Description id="SoftwarePlatform">.</Description>
    </component>
    <component>
      <Description id="HardwarePlatform">.</Description>
    </component>
    <component>
      <Description id="BrowserUA">.</Description>
    </component>
  </Description>
</RDF>
				
And my code looks like this (shortened):

######################################

// requestParameterID is the name of the request parameter

// get the request
Request request = ObjectModelHelper.getRequest(objectModel);

// now build a document from the rdf in the request 
factory = DocumentBuilderFactory.newInstance();
// requestParam should now be the xml from above
requestParam = factory.newDocumentBuilder().parse(
                new InputSource(new
StringReader(request.getParameter(requestParameterID))));

// now I should be able to do something like this, right?
requestParam.getElementsById("UserInteraction");

#######################################

--> this returns null. Why?

If I iterate through all Elements, I find it though (like this:)

#######################################

NodeList descriptions = requestParam.getElementsByTagName("Description");
String thisID;
for (int a = 0; a < descriptions.getLength(); a++) {
  if ((thisID =
descriptions.item(a).getAttributes().getNamedItem("id").getNodeValue()) !=
null) {
    if (thisID.equals("UserInteraction")) { 
       System.out.println("found userinteraction");
    }
  }
}
########################################

So I do find the right element and it does exist, but why can't I use
getElementById instead of going through all elements?

Thanx,
Stefan



AW: getElementById in request does not work

Posted by Stefan Pietschmann <sp...@inf.tu-dresden.de>.
Thanx, I was expecting something like that, but I thought there'd be an easy
way to somehow specify the ID attribute at document generation. 

Since I generate the requests I'm gonna try it with xml:id - hopefully this
will work.

Cheers,
Stefan

-----Ursprüngliche Nachricht-----
Von: Christian Stocker [mailto:chregu@bitflux.ch] 
Gesendet: Dienstag, 4. Januar 2005 10:27
An: dev@cocoon.apache.org
Cc: cocoon-dev@apache.org
Betreff: Re: getElementById in request does not work

Hi

On 4.1.2005 9:25 Uhr, Stefan Pietschmann wrote:
> Hi there,
> 
> I'm writing my custom action, and this is my problem with it:
> 
> I fetch a parameter from the request (which is sent with a form). It
> contains an small rdf snippet. I thought I'd be able to read it out with
> getelementbyid, but it doesn't work. The request parameter looks like
this:

Maybe this helps a little bit:

http://blog4.bitflux.ch/wiki/GetElementById_Pitfalls

(It's written for PHP, but the problem applies to other languages as 
well...)

chrgeu

> 
> <RDF>
>   <Description id="Profile">
>     <component>
>       <Description id="UserInteraction">.</Description>
>     </component>
>     <component>
>       <Description id="SoftwarePlatform">.</Description>
>     </component>
>     <component>
>       <Description id="HardwarePlatform">.</Description>
>     </component>
>     <component>
>       <Description id="BrowserUA">.</Description>
>     </component>
>   </Description>
> </RDF>
> 				
> And my code looks like this (shortened):
> 
> ######################################
> 
> // requestParameterID is the name of the request parameter
> 
> // get the request
> Request request = ObjectModelHelper.getRequest(objectModel);
> 
> // now build a document from the rdf in the request 
> factory = DocumentBuilderFactory.newInstance();
> // requestParam should now be the xml from above
> requestParam = factory.newDocumentBuilder().parse(
>                 new InputSource(new
> StringReader(request.getParameter(requestParameterID))));
> 
> // now I should be able to do something like this, right?
> requestParam.getElementsById("UserInteraction");
> 
> #######################################
> 
> --> this returns null. Why?
> 
> If I iterate through all Elements, I find it though (like this:)
> 
> #######################################
> 
> NodeList descriptions = requestParam.getElementsByTagName("Description");
> String thisID;
> for (int a = 0; a < descriptions.getLength(); a++) {
>   if ((thisID =
> descriptions.item(a).getAttributes().getNamedItem("id").getNodeValue()) !=
> null) {
>     if (thisID.equals("UserInteraction")) { 
>        System.out.println("found userinteraction");
>     }
>   }
> }
> ########################################
> 
> So I do find the right element and it does exist, but why can't I use
> getElementById instead of going through all elements?
> 
> Thanx,
> Stefan
> 

-- 
christian stocker | Bitflux GmbH | schoeneggstrasse 5 | ch-8004 zurich
phone +41 1 240 56 70 | mobile +41 76 561 88 60  | fax +41 1 240 56 71
http://www.bitflux.ch  |  chregu@bitflux.ch  |  gnupg-keyid 0x5CE1DECB


Re: getElementById in request does not work

Posted by Christian Stocker <ch...@bitflux.ch>.
Hi

On 4.1.2005 9:25 Uhr, Stefan Pietschmann wrote:
> Hi there,
> 
> I'm writing my custom action, and this is my problem with it:
> 
> I fetch a parameter from the request (which is sent with a form). It
> contains an small rdf snippet. I thought I'd be able to read it out with
> getelementbyid, but it doesn't work. The request parameter looks like this:

Maybe this helps a little bit:

http://blog4.bitflux.ch/wiki/GetElementById_Pitfalls

(It's written for PHP, but the problem applies to other languages as 
well...)

chrgeu

> 
> <RDF>
>   <Description id="Profile">
>     <component>
>       <Description id="UserInteraction">.</Description>
>     </component>
>     <component>
>       <Description id="SoftwarePlatform">.</Description>
>     </component>
>     <component>
>       <Description id="HardwarePlatform">.</Description>
>     </component>
>     <component>
>       <Description id="BrowserUA">.</Description>
>     </component>
>   </Description>
> </RDF>
> 				
> And my code looks like this (shortened):
> 
> ######################################
> 
> // requestParameterID is the name of the request parameter
> 
> // get the request
> Request request = ObjectModelHelper.getRequest(objectModel);
> 
> // now build a document from the rdf in the request 
> factory = DocumentBuilderFactory.newInstance();
> // requestParam should now be the xml from above
> requestParam = factory.newDocumentBuilder().parse(
>                 new InputSource(new
> StringReader(request.getParameter(requestParameterID))));
> 
> // now I should be able to do something like this, right?
> requestParam.getElementsById("UserInteraction");
> 
> #######################################
> 
> --> this returns null. Why?
> 
> If I iterate through all Elements, I find it though (like this:)
> 
> #######################################
> 
> NodeList descriptions = requestParam.getElementsByTagName("Description");
> String thisID;
> for (int a = 0; a < descriptions.getLength(); a++) {
>   if ((thisID =
> descriptions.item(a).getAttributes().getNamedItem("id").getNodeValue()) !=
> null) {
>     if (thisID.equals("UserInteraction")) { 
>        System.out.println("found userinteraction");
>     }
>   }
> }
> ########################################
> 
> So I do find the right element and it does exist, but why can't I use
> getElementById instead of going through all elements?
> 
> Thanx,
> Stefan
> 

-- 
christian stocker | Bitflux GmbH | schoeneggstrasse 5 | ch-8004 zurich
phone +41 1 240 56 70 | mobile +41 76 561 88 60  | fax +41 1 240 56 71
http://www.bitflux.ch  |  chregu@bitflux.ch  |  gnupg-keyid 0x5CE1DECB