Reputation: 11
I am new to Saxon.
In my java application, I have a requirement that I need to XQuery an existing dom4j document. The XQuery is to order few elements in an descending order by serialNo:
<?xml version="1.0" encoding="UTF-8"?>
<dataOfBooks:DataOfBooks xmlns:dataOfBooks="DataOfBooks">
<Id>ID123</Id>
<books>
<book>
<name>ccc</name>
<serialNo>77</serialNo>
</book>
<book>
<name>aaa</name>
<serialNo>99</serialNo>
</book>
</books>
</dataOfBooks:DataOfBooks>
Once I get the XQuery results, I need to add those back to the above existing document. I tried using net.sf.saxon.s9api. I was able to get the XQuery results back as below:
<?xml version="1.0" encoding="UTF-8"?>
<result:sequence
xmlns:result="http://saxon.sf.net/xquery-results"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<result:element>
<book xmlns:data="dataOfBooks">
<name>aaa</name>
<serialNo>99</serialNo>
</book>
<book xmlns:data="dataOfBooks">
<name>aaa</name>
<serialNo>77</serialNo>
</book>
</result:element>
</result:sequence>
But I have two issues. 1) the result has namespaces and extra stuff that I do not want. 2) It is not very clear to me as which Saxon API to use to add the XQuery results to the existing document. So that the resultant document looks as:
<?xml version="1.0" encoding="UTF-8"?>
<dataOfBooks:DataOfBooks xmlns:dataOfBooks="DataOfBooks">
<Id>ID123</Id>
<books>
<book>
<name>aaa</name>
<serialNo>99</serialNo>
</book>
<book>
<name>ccc</name>
<serialNo>77</serialNo>
</book>
</books>
</dataOfBooks:DataOfBooks>
One more question - I tried using dynamicContext and treeinfo classes since I though the usage of treeinfo API might be more optimal, but no luck. If you think, usage of TreeInfo API is efficient, I really appreciate a code example for my requirement. Your help is much appreciated.
Thanks in advance for your time and interest.
Upvotes: 0
Views: 437
Reputation: 163262
The fact that your XQuery code is producing unwanted namespaces is because your query is wrong, but we can't tell you how it is wrong unless you show us the code.
The result:sequence
in your output suggests that you have somehow contrived to ask for output in "wrapped" format, which suggests some kind of misuse of Saxon APIs. Again, without seeing your code, we can't tell you exactly what you have done wrong.
To make small changes to an existing document, leaving the rest unchanged, I would normally recommend XSLT over XQuery. In XSLT 3.0, you can sort the books by name using the following stylesheet:
<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="3.0">
<xsl:mode on-no-match="shallow-copy"/>
<xsl:template match="books">
<xsl:copy>
<xsl:perform-sort select="book">
<xsl:sort select="name"/>
</xsl:perform-sort>
</xsl:copy>
</xsl:template>
</xsl:transform>
In both XQuery and XSLT, the result of your query/transformation is a new document, which you can use in place of the original. If you want to make in-situ updates to an existing document, you can do this using XQuery Update; however Saxon does not support XQuery Update against documents in DOM4J format.
Saxon does allow you to capture the result of a query or transformation as a DOM4J Document, and you could use DOM4J APIs to graft this document (or rather, its outermost element) back into the original DOM4J document.
Later
You have now provided your code (you should have provided it as an edit to the original question, not as an answer).
I guess your DOMWriter is the DOM4J class of that name, which like much of DOM4J is rather badly documented. But I think it is copying the DOM4J tree to a DOM tree, which you definitely don't want to do. If you really want to copy the tree to make it convenient for Saxon, you should copy it to a Saxon tree, but for this use case it's best to leave it in DOM4J form. Use
DocumentBuilder builder = processor.newDocumentBuilder();
XdmNode inDoc = builder.wrap(dom4jdoc);
When you run your query, the resulting XdmValue will now be a sequence of XdmNode objects, each of which is a wrapper around a DOM4J Element node. These element nodes are still attached to the original DOM4J tree, and they still have their original namespaces. There is no need to serialize the result to lexical XML.
You can copy the result to a List value by writing
List<Element> sortedNodes = new ArrayList<Element>();
for (XdmItem item : result) {
sortedNodes.add(((Element)((XdmNode)item).getExternalNode()));
}
and then (if I read the DOM4J documentation correctly) you can replace the content of the containing books
element with
Element books = (Element)sortedNodes.get(0).getParent();
List booksContent = books.elements();
booksContent.clear();
booksContent.addAll(sortedBooks);
Upvotes: 1