I'm relatively new to XSLT, and I'm trying to come up with an elegant solution to the following problem -

I have a JSP that keeps a String array containing field names. These field names correspond to node names in an XML document. Each user of my web app can select a subset of these field names, and it is this subset of nodes and their values that I want to display using XSLT. I don't see a way to use this array in the stylesheet to conditionally display nodes without using a custom extension function - am I missing an easy solution?

So do you have something like a JSP page which contructs a select element with the arry values and then the users can select one or more options and you then invoke a transform of some data?
If so then you can pass the relevant String valuess to your transformer using its proprietary method before transforming and access to the values will be available via gloal xsl:param element(s) in the stylesheet. For more specific advice on the method you need to show some of the Java transform code and perhaps a small sample of xml data and xslt.

If not please explain further.

--

Joe (Co-author Beginning XML, 3rd edition)

Well basically I have a set of values in a Java data structure that I need to iterate over using XSLT. For example, I have a Java String array that contains the following data:

[node1, node3, node5]

Then I have XML that may look like this -

<page>
  <node1>Some text data</node1>
  <node2>Some more text data</node2>
  <node3>Even more text here...</node3>
  <node4>Still more text</node4>
  <node5>The final line of text.</node5>
</page>

I would like to be able to write an elegant stylesheet that would display only the textual data for the node names contained in the string array - in this case node1, node3, and node5. Any ideas?

If you're using Saxon 8, you can pass an array of strings directly as a parameter to your stylesheet (it will appear as a sequence of strings). Then the code is simply:

<xsl:param name="in" as="xs:string*" required="yes"/>

<xsl:template match="page">
  <page>
    <xsl:copy-of select="*[name() = $in]"/>
  </page>
</xsl:template>

You can do much the same in XSLT 1.0, but you will have to wrap the array of strings into an XML document structure, and pass that document as a parameter.



Michael Kay
http://saxon.sf.net/

Thanks for the quick reply Michael. I'm using the latest stable version of Xerces as my parser. Not sure how to best go about wrapping the string array in a document structure - can you elaborate? Thanks in advance.

Use DOM interfaces: createDocument, createElement, etc. Tedious but it works. Alternatively create the document as text:

for (int i...)
 out.println("<a>" + string[i] + "</a>")

and then parse the text; but take care about escaping special characters.

I wouldn't have suggested the XSLT 2.0 solution if I didn't think it was easier.



Michael Kay
http://saxon.sf.net/

Hi Michael,

seems you are one of the few Saxon specialists ;)
Michael, I need to return an array from Java method, e.g. String[].

Can you help me further on how to process the array on XSL side (I'm using Stylus Studio with Saxon XSLT processor).

What exactly do I need to code in XSLT to process this array?
Sorry, I didn't understand exactly what you were explaining...

The best place for Saxon-specific questions is the saxon-help list or forum at sourceforge.net.

I think the original thread was about calling XSLT from Java, and I think you're doing the opposite - calling Java from XSLT. You can return an array from an extension function. The way you process it depends on what's in the items of the array, but basically you process it as a sequence, for example

for $i in my:javaMethodReturningArray()
return ....

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference