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Posted to batik-users@xmlgraphics.apache.org by Jorg Heymans <jh...@domek.be> on 2004/08/04 10:00:45 UTC
Re: removing dynamically added nodes (from the update thread)
Hi Thomas,
Apologies for the late reply, here is a bit more info.
1) the code is running in an applet
2) I have a monitor class implementing all 4 listener classes
(Updatemanager, svgdocumentloader,gvttreebuilder,gvttreerenderer)
3) I have a class extending the svgloadeventdispatcher, and in
svgloadeventdispatchstarted() i assign the document instance
this.document=canvas.getSVGDocument()
4) in init() of the applet i have
canvas.setDocumentState(JSVGCanvas.ALWAYS_DYNAMIC);
canvas.addSVGLoadEventDispatcherListener(new SVGLoadMonitor());
canvas.addSVGDocumentLoaderListener(monitor);
canvas.addGVTTreeBuilderListener(monitor);
canvas.addGVTTreeRendererListener(monitor);
canvas.addUpdateManagerListener(monitor);
canvas.setURI(getClass().getClassLoader().getResource("base.svg")
.toExternalForm());
5) i am adding and removing DOM elements via checkboxes, so in
itemStateChanged(ItemEvent e) i do
.....
//ADDING elements (works)
String parser = XMLResourceDescriptor.getXMLParserClassName();
SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
final SVGDocument doc = (SVGDocument) f.createDocument(uri);
final Node documentNode = document.importNode(doc
.getElementsByTagName("g").item(0), true);
//find the node we need to append to
String xpath = "//*[@id='" + feature + "']";
final NodeList nodeList = org.apache.xpath.XPathAPI
.selectNodeList(document, xpath);
canvas.getUpdateManager().getUpdateRunnableQueue().invokeLater(
new Runnable() {
public void run() {
document.getDocumentElement().replaceChild(
documentNode, nodeList.item(0));
}
});
......
//REMOVING ELEMENTS (does not work)
final Element remove = document.getElementById("wta");
canvas.getUpdateManager().getUpdateRunnableQueue().invokeLater(
new Runnable() {
public void run() {
//EXCEPTION OCCURS HERE
remove.getParentNode().removeChild(remove);
}
});
6) The calls to getPreviousSibling() and getNextSibling() on the node i
want to remove :
getNodeName() -> "#text"
getNodeValue() -> a few blanks and newlines, seems correct
getNodeType() -> 3
7) Adding and removing happens in thread "RunnableQueue-0" according to
log4j. All other operations in thread "AWT-EventQueue-1".
Hope i haven't flooded you with too much info, if you need more info
just shout.
Regards
Jorg
Thomas DeWeese wrote:
> Hi Jorg,
>
> I have no idea why you are getting this error. I have
> never seen it. My initial suspicion is that you are removing
> the same element from two different threads. I would be
> curious to know what getPreviousSibling() and getNextSibling()
> return right before calling removeChild.
>
> I would also be interested in knowing how you add the
> elements to the DOM.
>
> Is this error totally reproducable? can you produce a
> reproducable standalone test case?
>
>
> Jorg Heymans wrote:
>
>> Hi,
>>
>>
>> I am able to add stuff to the DOM in the update thread
>> (getUpdateManager().getUpdateRunnableQueue().invokeLater() )
>>
>> Why is a simple removal then not working like i expect it to work?
>> I locate the node to remove using document.getElementById , making
>> sure with getLocalName() and getAttributes() that this is actually the
>> node i want to remove.
>>
>> Then in the update thread i am doing
>> removenode.getParent().removeChild(removenode) which results in
>> stacktrace ("g" being the element i want to remove)
>>
>> org.w3c.dom.DOMException: The child node (type: 1, name: g) is missing.
>> at org.apache.batik.dom.AbstractNode.createDOMException(Unknown Source)
>> at org.apache.batik.dom.AbstractParentNode$ChildNodes.remove(Unknown
>> Source)
>> at org.apache.batik.dom.AbstractParentNode.removeChild(Unknown Source)
>> at com.terrasel.osgis.batikapplet.SVGApplet$2.run(SVGApplet.java:187)
>> at org.apache.batik.util.RunnableQueue.run(Unknown Source)
>> at java.lang.Thread.run(Thread.java:534)
>>
>> The element i want to remove is the one i just dynamically added. I
>> think i am operating on a recent document instance because i can
>> actually *find* the element.
>>
>> Removing static elements always works, so where am I missing the sync
>> on the document instance?
>>
>>
>> Any hints?
>>
>>
>> Regards
>> Jorg
>>
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Attachments
Posted by Carsten Birn <Ca...@rose.de>.
Hi
Are mails with attachments not allowed on the Mailinglist...?
Or is there somekind of response time?
:-)
Carsten
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Re: removing dynamically added nodes (from the update thread)
Posted by Jorg Heymans <jh...@domek.be>.
Thomas DeWeese wrote:
<snip/>
>
> I am reasonably sure that the Document Element is not the
> parent of nodeList.item(0). In which case the above call will
> slightly corrupt our DOM. I've added additional checks so an
> error will be raised in this condition in the future.
okay.
>
> You probably want:
>
> Element elt = (Element)nodeList.item(0);
> elt.getParentNode().replaceChild(documentNode, elt);
Works fine now, thanks !
>
> Also why are you dragging in XPath just to do getElementById?
>
>> String xpath = "//*[@id='" + feature + "']";
>> final NodeList nodeList = org.apache.xpath.XPathAPI
>> .selectNodeList(document, xpath);
I know, leftover from more complicated node searches :)
Thanks again
Jorg Heymans
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Re: removing dynamically added nodes (from the update thread)
Posted by Thomas DeWeese <Th...@Kodak.com>.
Hi Jorg,
I believe this is caused by a bug in your code.
However it is probably a bug that we should have caught
and raised an error on. In particular:
Jorg Heymans wrote:
> document.getDocumentElement().replaceChild(
> documentNode, nodeList.item(0));
I am reasonably sure that the Document Element is not the
parent of nodeList.item(0). In which case the above call will
slightly corrupt our DOM. I've added additional checks so an
error will be raised in this condition in the future.
You probably want:
Element elt = (Element)nodeList.item(0);
elt.getParentNode().replaceChild(documentNode, elt);
Also why are you dragging in XPath just to do getElementById?
> String xpath = "//*[@id='" + feature + "']";
> final NodeList nodeList = org.apache.xpath.XPathAPI
> .selectNodeList(document, xpath);
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