Hi Indika,

I tested your point and found the cause. Simply, in the second case there is no parent for the root element. Therefore, evaluating an XPath containing <hello> element will cause an exception. But if you evaluate an XPath like, //anotherthing/insideanother, you will get the desired result.

So the solution I would like to suggest in this case is to first check the parent of the element. If the parent is an instance of OMDocument then we need not detach (if you need to build then just use OMNode#build()). If the parent is an instance of OMElement then you need to detach since you want the element to be isolated from the connecting tree.

Thanks,
Saliya

On Sun, Jun 21, 2009 at 11:06 AM, indika kumara <indika.kuma@gmail.com> wrote:
        Hi Saliya
      
        Following shown my scenarios.

 
       Scenario 1  - without detach on root element

        String str = "<hello><something>wow nice</something><anotherthing><insideanother>great</insideanother></anotherthing></hello>";
        XMLStreamReader parser = XMLInputFactory.newInstance().
                createXMLStreamReader(new ByteArrayInputStream(str.getBytes()));
        StAXOMBuilder builder = new StAXOMBuilder(parser);
        OMElement root = builder.getDocumentElement();
//        root.detach();

        AXIOMXPath xpath = new AXIOMXPath("//hello/something");
        OMElement node = (OMElement) xpath.selectSingleNode(root);
        System.out.println(node == null);
        if (node != null) {

            System.out.println(node.getText());
        }


      Out put :

       false
       wow nice


       Scenario 2 - with  detach on root element

        String str = "<hello><something>wow nice</something><anotherthing><insideanother>great</insideanother></anotherthing></hello>";
        XMLStreamReader parser = XMLInputFactory.newInstance().
                createXMLStreamReader(new ByteArrayInputStream(str.getBytes()));
        StAXOMBuilder builder = new StAXOMBuilder(parser);
        OMElement root = builder.getDocumentElement();
        root.detach();

        AXIOMXPath xpath = new AXIOMXPath("//hello/something");
        OMElement node = (OMElement) xpath.selectSingleNode(root);
        System.out.println(node == null);
        if (node != null) {

            System.out.println(node.getText());
        }
      
       Output

       true


   In second case , XPath  have not been evaluated correctly.

Thanks
Indika

On Sat, Jun 20, 2009 at 9:40 PM, Saliya Ekanayake <esaliya@gmail.com> wrote:
Hi,

Um, I am not really clarified with the problem here. I agree that the full tree should be built before we can evaluate XPath. Adding the element to a new OMDocument, however, just to get this done seems not right. Additionally, the original OMDocument created by the builder will be there even if you detach the element. Detach will only remove the element from the tree to which it belongs. To check this, you can get the builder from the detached element and ask for the OMDocument.  IMHO, we can call result.build() if necessary.

Btw. I am not clear why XPath doesn't work on the detached element. I did a simple test as follows and XPath worked, may be I have missed something (please let me know if so).

    public static void main(String[] args) throws XMLStreamException, JaxenException {
        String str = "<hello><something>wow nice</something><anotherthing><insideanother>great</insideanother></anotherthing></hello>";
        StAXOMBuilder builder = new StAXOMBuilder(new ByteArrayInputStream(str.getBytes()));
        OMElement root = builder.getDocumentElement();
       
        OMDocument doc = builder.getDocument();
        System.out.println(doc == null);

        OMElement anotherthing = root.getFirstChildWithName(new QName("anotherthing"));
        anotherthing.detach();

        doc = ((StAXOMBuilder)anotherthing.getBuilder()).getDocument();
        System.out.println(doc == null);

        AXIOMXPath xpath = new AXIOMXPath("//insideanother");
        OMElement node = (OMElement) xpath.selectSingleNode(anotherthing);
        System.out.println(node.getText());
    }

Thanks,
Saliya

On Sat, Jun 20, 2009 at 4:45 AM, Andreas Veithen <andreas.veithen@gmail.com> wrote:
StAXOMBuilder actually already creates an OMDocument (which can be
retrieved by the getDocument method). The important thing is that we
need to make sure that the Axiom tree is fully built before closing
the input stream. I guess that the detach method is used because it
has the side effect of fully building the element and because
OMDocument has no method to build the entire tree (see WSCOMMONS-479).

This gives us two solutions:

- Use StAXOMBuilder#getDocument and iterate over its children to make
sure the document is fully built.
- Continue to use "detach" and add the element to a new document, as
you suggested. Note that you should not use OMDocumentImpl directly,
but create it using the OMFactory.

Andreas

On Fri, Jun 19, 2009 at 09:30, indika kumara<indika.kuma@gmail.com> wrote:
> Devs
>
> $subject is due to we do  'detach()'  on picked resource OMElement .
> If I add detached element to a OMDocument as a child, it works
>
> Existing code  SImpleURLRegistry
>
> result.detach();
> inputStream.close();
>
>
> Modified code
>
> result.detach();
> OMDocumentImpl omDocument = new OMDocumentImpl();
> omDocument.addChild(result);
> inputStream.close();
>
>
> Are there any best solution other than what I did ?  I haven't deep
> AXIOM knowledge?  Could anyone help me?
>
> Thanks
> Indika
>
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--
Saliya Ekanayake
http://www.esaliya.blogspot.com
http://www.esaliya.wordpress.com




--
Saliya Ekanayake
http://www.esaliya.blogspot.com
http://www.esaliya.wordpress.com