The DOM standard describes the behaviour of NodeIterator after deletion in
DOM Level 2 Traversal and Range
refer
http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113/traversal.html#Iterator-overview
I quote the appropriate paragraphs:
"If the reference node is removed from the list being iterated over, a
different node is selected as the reference node. If the reference node's
position is before that of the NodeIterator, which is usually the case after
nextNode() has been called, the nearest node before the iterator is chosen
as the new reference node. Suppose we remove the "D" node, starting from the
following state:
A B C [D] * F G H I
The "C" node becomes the new reference node, since it is the nearest node to
the NodeIterator that is before the iterator:
A B [C] * F G H I
If the reference node is after the NodeIterator, which is usually the case
after previousNode() has been called, the nearest node after the iterator is
chosen as the new reference node. Suppose we remove "E", starting from the
following state:
A B C D * [E] F G H I
The "F" node becomes the new reference node, since it is the nearest node to
the NodeIterator that is after the iterator:
A B C D * [F] G H I"I hope this helps.Best regards,Denny
----- Original Message -----
From: "Joerg Toellner" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, December 10, 2003 9:00 AM
Subject: DOMNodeIterator - Position after deleting a node
> Dear Group and Xerces-Gods,
>
> maybe a simple question for you but a big problem for me. Haven't found
> a hint within doc, faq and group (or maybe i'm to dumb to understand
> it).
>
> The situation:
> --------------
> I have to "cleanup" a DOMTree after processing it. I load a "template"
> XML File, parse it, change/add/delete some nodes/values/attributes as
> neccesary and save it again under another filename. After manipulating
> the XML-Document in memory maybe in a ugly state (not in the meaning of
> correctness. It is still wellformed of course). But some nodes are empty
> after processing (has had a value before processing). Some attributes
> may be obsolete now, i don't want comment-nodes in the resulting xml
> file (against i want them for documentation in the template of course)
> a.s.o.
>
> So after all processing i do a (let me call it a) "cleanup". I create a
> DOMNodeIterator for the whole doctree. FastForward (with nextNode) to
> the last node and traverse the iterator backwards (with previousNode)
> researching each node and do what have to be done with it.
>
> Now my question:
> ----------------
> As stated above in some cases i need to remove the actual node (and the
> whole subtree under it). This works fine, but then i'm in doubt about
> the position of the DOMNodeIterator as i think it is LIVE, isn't it?
> Which node i'll get if i call nextNode/previousNode after deleting the
> actual Node?
>
> Please find my related code below for your information what i do yet.
> What must i do to set my nd-variable (see my code) to the correct
> previous node of the now deleted actual node? I found no method to get
> the actual node from the DOMNodeIterator without moving the
> actualpointer of the iterator one forward or backward. Or I'm missing
> here sth.? Is the best/only way to be sure that i have the right node to
> do a nextNode/previousNode call to get the now actual node without
> overjumping a node which then will not being processed/cleanup-ed?
>
> I'm always thankful for suggestions to improve my surely inefficient and
> hopefully not to buggy code (who laughs there? *GRUMBLE*) :-)). Please
> if you see sth. could done better or safer feel free to let me know. I
> like to learn and understand.
>
> Thanks in advance for your help and cooperation.
>
> CU all
> Joerg
>
> //--------------------------------------
> // START OF CODE SNIPPET
> //--------------------------------------
>
> void dom_TreeCleanup(DOMDocument *doc)
> {
> DOMNodeIterator *dni;
> DOMNode *nd, *tmpnd;
> DOMNamedNodeMap *attrs;
> DOMAttr *atnd;
> int type;
>
> // create Iterator
> dni = doc->createNodeIterator(doc->getDocumentElement(),
> DOMNodeFilter::SHOW_ALL, NULL, TRUE);
>
> // Fast forward to get the last node as the actual node
> while((tmpnd = dni->nextNode()) != NULL)
> nd = tmpnd;
>
> // Process the IteratorNodes backwards
> while(nd != NULL)
> {
> // Get the nodetype to decide what to do (different nodes are
> handled differently)
> type = nd->getNodeType();
>
> if(type == DOM_COMMENT_NODE)
> {
> // Don't need commentnodes anymore
> dom_RemoveNode(nd);
> }
> else if(type == DOM_ELEMENT_NODE)
> {
> // Aaaah! an Element Node. This needs attribute related
> processing
> // so get the attributes for further investigation
> attrs = nd->getAttributes();
>
> // if there are attributes -> research them
> if(attrs != NULL)
> {
> atnd = (DOMAttr *) attrs->getNamedItem(X(DOM_DEL_TAG));
> if(atnd != NULL)
> {
> if(strcmp(X2C(atnd->getValue()), "1") == 0)
> {
> // If the delflag attribute value is 1 remove
> that node
> dom_RemoveNode(nd);
> }
> else
> {
> // If the delflag value is zero leave the node
> alone but
> // remove the delflag attributenode
> dom_RemoveAttr(atnd);
> }
> }
> }
>
> // General Cleanup that belongs to every type of node
> // If the actual node now (after nodetype-specific
> processing) don't have any
> // attributes AND no childnodes it is useless -> remove it
> if(!(nd->hasAttributes()) && !(nd->hasChildNodes()))
> {
> dom_RemoveNode(nd);
> }
> }
>
> // get the previous node as the new actual node
> nd = dni->previousNode();
> }
> }
>
> void dom_RemoveNode(DOMNode *nd)
> {
> nd->getParentNode()->removeChild(nd);
> nd->release();
> }
>
> void dom_RemoveAttr(DOMAttr *attr)
> {
> attr->getOwnerElement()->removeAttributeNode(attr);
> }
>
> //--------------------------------------
> // END OF CODE SNIPPET
> //--------------------------------------
>
>
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