Re: Extracting information from XML

Tuesday, June 1, 2010, 4:26:07 PM, Eric Willigers wrote:

> Hello,
>
> I'm trying to extract information from some XML files, but I'm 
> encountering a couple of unusual cases (below).
>
> Any suggestions are welcome.
>
> Lots of thanks,
> Eric.
>
>
>
> Question 1.
>
> We want to extract "hyphenated-name" nodes from some XML:-
>
> <root>
>      <hyphenated-name data="first"/>
>      <hyphenated-name data="second"/>
> </root>
>
> I would like to use
>      <#list document.root.hyphenated-name as node>
> but the hyphen prevents this from working. None of these work either:-
>      <#list document.root."hyphenated-name" as node>
>      <#list document.root.'hyphenated-name' as node>
>      <#list document.root.`hyphenated-name` as node>

I find it strange that people always try to accidentally hit the right
syntax... there is a documentation! Anyway, the thing to know here is
that foo.bar and foo["bar"] is the same. So the solution is:

  <#list document.root["hyphenated-name"] as node>

> I ended up using
>      <#list document.root?children as child>
>        <#if child?node_type = 'element' && child?node_name = 
"hyphenated-name">>
>
> Are there better options?
>
>
>
>
> Question 2.
>
> How should I extract an attribute from an XML node, when the name of the
> attribute is given by a variable?
> e.g. is there something like ${node.@$attrName}
>
>
> Here's my XML:-
>
> <root>
>      <attr name="a" />
>      <attr name="b" />
>
>      <data b="B" a="A" />
> </root>
>
>
> I tried
>
> <#list document.root.data as data>
>    <#list document.root.attr as attr>
>      ${data.@$attr.@name}
>    </#list>
> </#list>
>
> but this caused
> SEVERE: javax.xml.transform.TransformerException: A node test that 
> matches either NCName:* or QName was expected.
>
> A bug?

No, the problem is that the $ thingy is not resolved there, it never
was. Actually, $foo is never resolved in FreeMarker, only ${foo}, but
even that only in static text parts and in string literals. So this is
again a [] thing. You can have any kind of complex expression inside
[] as far as it evaluates to a string, so: ${data["@" + attr.@name]}

-- 
Best regards,
 Daniel Dekany


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