Removing the XML node from a DOM object

[Paul Policarp]

Hi.

I'm using the w3 DOM API for XML manipulation and need to add a subtree (constructed by using "parse()" on a ByteArrayInputStream derived from a string) to another DOM.

I get a org.w3c.dom.DOMException: WRONG_DOCUMENT_ERR: A node is used in a different document than the one that created it.

I think this is because the DOM created with parse() also contains the <?xml version...etc> tag. How can I remove it?

Here's the code sample:

Document inlineDoc  = domOfString(inlineconfig);
		
		configNode.appendChild(inlineDoc.getDocumentElement());
	}

	public Document domOfString(final String source) throws NetconfException {
		Document result = null;
		ByteArrayInputStream bais = new ByteArrayInputStream(source.getBytes());
		try {
			result = domBuilder.parse(bais);
		} catch (Exception e) {
			throw new NetconfException("Cannot parse XML data!");
		}
		return result;
	}

[Rob Spoor]

Node, which is extended by both Document and Element, has methods getParentNode() and removeChild(Node). So you can detach any Node from its parent as such:

Node parent = node.getParentNode();
if (parent != null)
{
    parent.removeChild(node);
}

[Paul Policarp]

Ok, but my XML looks like this:

<?xml version=1.0...>
<snapshot>
<node> value<node>
.
.
.
</snapshot>

I need everything BUT "<?xml version=1.0...>" as a DOM. Can I remove it with removeChild? Does it have a parent node?

[Rob Spoor]

What happens if you print out parent?

[Paul Clapham]

Paul Policarp wrote:I get a org.w3c.dom.DOMException: WRONG_DOCUMENT_ERR: A node is used in a different document than the one that created it.

I think this is because the DOM created with parse() also contains the <?xml version...etc> tag. How can I remove it?

No, that's a completely wrong guess at the problem. The problem is exactly what the error message says it. To fix the problem, have a look at the Document.importNode method.

[Paul Policarp]

This is how I amended the code:

Document inlineDoc  = domOfString(inlineconfig);
		Node node = inlineDoc.getDocumentElement();
		Node parent = node.getParentNode();  
		System.out.println("*****"+parent.getNodeName());
		System.out.println("++++++"+node.getNodeName());

And then inserted your code. This is my output:

*****#document
++++++snapshot

And then I get a NullPointerException on

configNode.appendChild(inlineDoc.getDocumentElement());

[Paul Clapham]

Paul Policarp wrote:Ok, but my XML looks like this:

<?xml version=1.0...>
<snapshot>
<node> value<node>
.
.
.
</snapshot>

I need everything BUT "<?xml version=1.0...>" as a DOM. Can I remove it with removeChild? Does it have a parent node?

No, that's a completely wrong understanding of DOM. Your DOM only contains the nodes of the document. It doesn't "contain" the prolog from the text version of the document; the prolog is produced when you serialize the DOM.

If you don't want your serialized document to contain a prolog, then do something differently in the serialization process to exclude the prolog.

[Paul Policarp]

Thanks, I didn't know all these things. Import node worked like a charm once I got the hang of it.