Hi Siggi
I had a try at this and it seemed to work to me.
To select, say, all FUNCTION nodes in the whole document which contain
at least one SIGNAL-REF element whose idRef attribute has a particular
value (say 'sig4'), parse the document into an XmlObject and call (on
that same XmlObject):
xmlObj.selectPath("//FUNCTION[.//[EMAIL PROTECTED]'sig4']]");
You will get an array of FUNCTION nodes. If you wanted only the
SIGNAL-REF nodes which match 'sig4' you would do something like this:
xmlObj.selectPath("//FUNCTION//[EMAIL PROTECTED]'sig4']");
Similarly for FRAME nodes.
Finding which SIGNAL nodes are referred to by a given (e.g.) FRAME is
slightly different. Having gotten the XmlObject that represents the
whole document first create an XmlCursor using newCursor(), then
navigate to the FRAME of interest. Then do cursor.getObject(). That will
give you an XmlObject representing that FRAME element. You can then
call:
frameXmlObj.selectPath("//[EMAIL PROTECTED]//@idRef]");
This will return all nodes within the whole document having an attribute
called id which has the same value as any of the idRef attributes in
_any descendant_ of this node (this node being the FRAME node).
If you want to be even more precise you could do something like this:
frameXmlObj.selectPath("//[EMAIL PROTECTED]//@idRef]");
which will return all SIGNAL nodes within the whole document having an
attribute called id which has the same value as any of the idRef
attributes in _any descendant_ of this node (this node being the FRAME
node).
(If you wanted to, you could adopt the same approach to the first
example I gave and replace the hardcoded 'sig4' with navigating to the
SIGNAL node and passing in $this/@id instead of 'sig4').
Hope that helps. As I say I'm not really an XPath expert and this is
really becoming more about XPath than about XmlBeans.
Cheers,
Lawrence
> -----Original Message-----
> From: Siegfried Baiz [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, April 04, 2006 1:36 AM
> To: [email protected]
> Subject: Re: selectPath with FilterExpression using $this
>
> Lawrence,
>
> My Xml-Document looks somehow like this:
> <SAMPLE-FRAG>
> <ELEMENTS>
> <FRAMES>
> <FRAME>
> <SIGNAL-INSTANCE>
> <SIGNAL-REF idRef="sig1"/>
> </SIGNAL-INSTANCE>
> <SIGNAL-INSTANCE>
> <SIGNAL-REF idRef="sig2"/>
> </SIGNAL-INSTANCE>
> </FRAME>
> <FRAME>
> <SIGNAL-INSTANCE>
> <SIGNAL-REF idRef="sig2"/>
> </SIGNAL-INSTANCE>
> <SIGNAL-INSTANCE>
> <SIGNAL-REF idRef="sig3"/>
> </SIGNAL-INSTANCE>
> <SIGNAL-INSTANCE>
> <SIGNAL-REF idRef="sig4"/>
> </SIGNAL-INSTANCE>
> </FRAME>
> </FRAMES>
> <FUNCTIONS>
> <FUNCTION>
> <INPUT-PORT>
> <SIGNAL-REF idRef="sig1"/>
> </INPUT-PORT>
> <OUTPUT-PORT>
> <SIGNAL-REF idRef="sig2"/>
> </OUTPUT-PORT>
> <OUTPUT-PORT>
> <SIGNAL-REF idRef="sig4"/>
> </OUTPUT-PORT>
> </FUNCTION>
> <FUNCTION>
> <INPUT-PORT>
> <SIGNAL-REF idRef="sig2"/>
> </INPUT-PORT>
> <INPUT-PORT>
> <SIGNAL-REF idRef="sig3"/>
> </INPUT-PORT>
> <OUTPUT-PORT>
> <SIGNAL-REF idRef="sig4"/>
> </OUTPUT-PORT>
> </FUNCTION>
> </FUNCTIONS>
> <SIGNALS>
> <SIGNAL id="sig1"/>
> <SIGNAL id="sig2"/>
> <SIGNAL id="sig3"/>
> <SIGNAL id="sig4"/>
> </SIGNALS>
> </ELEMENTS>
> </SAMPLE-FRAG>
>
> I'm generally interested in resolving relations between
> the tree containers FUNCTIONS, FRAMES and SIGNALS.
>
> For example:
> Which FUNCTION- rsp. FRAME-Nodes refer to given Signal?
> Which SIGNAL-Nodes are refererd by a given FRAME rsp. FUNCTION?
>
>
> By the way I've checked my classpath:
> It contains saxon8.jar but not saxon8-dom.jar.
>
> Thanks and Cheers,
>
> Siggi
>
>
>
>
>
> Lawrence Jones wrote:
>
> >I too have had a go at this, but I too am not an XPath
> expert.
> >
> >First of all make sure you have _all of_ saxon8.jar and
> saxon8-dom.jar
> >and xbean_xpath.jar (in addition to the normal xbean.jar and
the
> JSR 173
> >jar) on your classpath. Not having saxon8-dom.jar can cause
> strange
> >errors. Not having xbean_xpath.jar just means that no XPath
will
> work.
> >
> >Other than that I think it might just be that we're not
> passing in the
> >right XPath. Siegfried, can you attach an example XML
instance
> document
> >for which you are expecting this to work?
> >
> >Here's the one I tried:
> >
> ><elem1 xmlns=\"http://laj.org/test\"; >
> > <elem11 id=\"123\" >text11</elem11>
> > <elem21 id=\"456\" >text11</elem21>
> > <elem12 idRef=\"123\" />
> > <elem13 idRef=\"456\" />
> > <elem14 idRef=\"123\" />
> > <elem15 idRef=\"456\" />
> > <elem16 idRef=\"123\" />
> > <elem17 idRef=\"789\" />
> ></elem1>
> >
> >And here are the issues I see.
> >
> >1. The element on which you perform the selectPath() call
seems
> to
> >represent the root as far as the call to selectPath() is
> concerned. So
> >if e.g. you passed in only the XmlObject for <elem11> above
> you should
> >not expect any of the other elements to be returned
regardless
> of the
> >XPath passed in.
> >
> >2. But it is likely that the elements with idRef in them
are
> _not_
> >children of the element with id in them. Rather it is
likely
> that they
> >are all members of some larger document element such as
<elem1>
> above.
> >So to get the selectPath() to even consider them you would
> need to pass
> >in the XmlObject for <elem1> (or at least some element that
is
> a root to
> >all of the results you expect).
> >
> >3. But then the path to the id attribute is no longer
> $this/@id as that
> >would only match the _root_ element (<elem1> in this case)
> having an id
> >attribute. Exactly what you need to pass in depends on what
> you want to
> >do - if you want to find all idRefs that match _any_ id
> attribute
> >anywhere in the document then you probably want $this//@id
> instead.
> >
> >4. I tried the XPath //[EMAIL PROTECTED]//@id] on the complete
> document
> >above (i.e. I executed selectPath() on the XmlObject
representing
> ><elem1>) and printed out the list of XmlObjects returned
from
> >selectPath(). I got:
> >
> >Number of results = 5
> >results[0] = <xml-fragment idRef="123"/>
> >results[1] = <xml-fragment idRef="456"/>
> >results[2] = <xml-fragment idRef="123"/>
> >results[3] = <xml-fragment idRef="456"/>
> >results[4] = <xml-fragment idRef="123"/>
> >
> >which is what I'd expect i.e. I get all the nodes with an
> idRef that
> >matches any id attribute somewhere else in the document (and
I
> don't get
> >those that do not match). Not sure why they are
xml-fragment's
> rather
> >than proper individual elements with proper QNames but that's
a
> >different issue.
> >
> >5. Note that replacing '$this' with '.' (i.e. XPath =
> //[EMAIL PROTECTED]//@id)
> >gave me an empty result set. My guess is that '.' is
> evaluated
> >dynamically (i.e. it means the current node that the query
has
> evaluated
> >to) compared to $this which is bound statically at the
> beginning to the
> >root node that you pass in. (With the '.' version of the
> XPath I think
> >you are looking for a node which has both an id and an
idRef
> attribute
> >where the values are the same - which is a slightly
different
> query.)
> >
> >I haven't tried this exhaustively - I'm not sure what would
> happen if
> >some of the id or idRef attributes were on elements at
deeper
> levels.
> >But anyway I hope that helps get started.
> >
> >Cheers,
> >
> >Lawrence
> >
> >
> >
> >>-----Original Message-----
> >>From: Radu Preotiuc-Pietro
> >>Sent: Thursday, March 30, 2006 1:56 PM
> >>To: [email protected]
> >>Subject: RE: selectPath with FilterExpression using $this
> >>
> >>I was curious to try this myself with the new Saxon 8.6
> integration
> >>(available from the SVN head only, for the moment) and
what I
> found is
> >>that the path you are suggesting ("//[EMAIL PROTECTED]/@id]") works
(no
> >>exception) but for some reason doesn't return anything. On
the
> other
> >>hand, "//[EMAIL PROTECTED]'1'" returns the expected result, so on
one
> hand I
> >>
> >>
> >am
> >
> >
> >>wondering if this is maybe a bug in the free version of
> Saxon and on
> >>
> >>
> >the
> >
> >
> >>other you can use this to workaround the problem by doing
> >>.selectPath("//[EMAIL PROTECTED]'" + node.getId() + "'").
> >>
> >>If anyone else has other insights into why the original
path
> does not
> >>work (with more Xpath/Saxon knowledge), I'd also be
interested
> to
> >>
> >>
> >know.
> >
> >
> >>Thanks,
> >>Radu
> >>
> >>-----Original Message-----
> >>From: Cezar Andrei
> >>Sent: Wednesday, March 29, 2006 3:30 PM
> >>To: [email protected]
> >>Subject: RE: selectPath with FilterExpression using $this
> >>
> >>Hi Siegfried,
> >>
> >>I'm not an expert in xpath/xquery but I'm pretty sure that
> $this
> >>
> >>
> >doesn't
> >
> >
> >>represent the internal current node that is processed by
the
> engine.
> >>
> >>So you'll probably want to rewrite the expression to
something
> like
> >>this:
> >>xo.selectPath(".//[EMAIL PROTECTED]//@id]");
> >>
> >>As for $this, it's just a variable that is bound to the
> XmlObject that
> >>you are calling the selectPath method from. The '$this'
> construction
> >>
> >>
> >is
> >
> >
> >>not in the latest XPath/Xquery spec so it was deprecated,
> instead "."
> >>should be used.
> >>
> >>The current XmlObject can be bound to any user specified
> variable name
> >>as in the following example:
> >>
> >> XmlOptions options = new XmlOptions();
> >> options.setXqueryCurrentNodeVar("myVariable");
> >> XmlObject[] res = xo.selectPath("declare variable
$myVariable
> >>external; $myVariable//el1", options);
> >>
> >>Which is equivalent to:
> >>
> >> XmlObject[] res = xo.selectPath(".//el1", options);
> >>
> >>And to the following (since in the context of the xpath
> engine the xo
> >>
> >>
> >is
> >
> >
> >>considered the root):
> >>
> >> XmlObject[] res = xo.selectPath("//el1", options);
> >>
> >>Since we don't control Saxon, we can't promise that
expressions
> >>confirming to the spec will work. We can only work on
making
> sure we
> >>make the right calls into Saxon.
> >>
> >>Cezar
> >>
> >>
> >>
> >>
> >>>-----Original Message-----
> >>>From: Siegfried Baiz [mailto:[EMAIL PROTECTED]
> >>>Sent: Tuesday, March 14, 2006 12:11 PM
> >>>To: [email protected]
> >>>Subject: selectPath with FilterExpression using $this
> >>>
> >>>Hello,
> >>>
> >>>for a given XmlObject xo with an ID-Attribute 'id', I've
> tried to
> >>>launch the following xpath-expression:
> >>>
> >>> xo.selectPath("//[EMAIL PROTECTED]/@id]")
> >>>
> >>>in order to get all nodes (with idRef-Attribute) refering
to
> my node
> >>>
> >>>
> >>xo.
> >>
> >>
> >>>Unfortunatlly this expression seems not to work. I always
get
> an
> >>>java.lang.ArrayIndexOutOfBoundsException from the underlying
> >>>
> >>>
> >>>
>
>net.sf.saxon.expr.XPathContextMajor.setLocalVariable(XPathContextMajor.
j
> >
> >
> >>av
> >>
> >>
> >>>a:213)
> >>>
> >>>At
> >>>
> >>>
> >>>
>
>http://xmlbeans.apache.org/docs/2.0.0/guide/conSelectingXMLwithXQueryPa
t
> >
> >
> >>hX
> >>
> >>
> >>>Path.html
> >>>I found the following notice:
> >>> "Notice in the query expression that the variable $this
> >>>
> >>>
> >>represents
> >>
> >>
> >>> the current context node (the XmlObject that you are
> querying
> >>>
> >>>
> >>from).
> >>
> >>
> >>> In this example you are querying from the document level
> >>>
> >>>
> >>XmlObject."
> >>
> >>
> >>>After reading that sentence I've been thinking, that $this
is
> >>>
> >>>
> >somehow
> >
> >
> >>>similar to "curent()" in XSLT, but maybe a got the
meaning
> wrong.
> >>>
> >>>Does anyone know whats the problem here rsp.
> >>>is there a better way to accomplish the same thing?
> >>>
> >>>Thanks a lot,
> >>>
> >>>Siggi
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >---------------------------------------------------------------------
> >
> >
> >>>To unsubscribe, e-mail: [EMAIL PROTECTED]
> >>>For additional commands, e-mail: [EMAIL PROTECTED]
> >>>
> >>>
> >>
> >>
>
>_______________________________________________________________________
> >
> >
> >>Notice: This email message, together with any attachments,
may
> >>
> >>
> >contain
> >
> >
> >>information of BEA Systems, Inc., its subsidiaries and
> >>
> >>
> >affiliated
> >
> >
> >>entities, that may be confidential, proprietary, copyrighted
> >>
> >>
> >and/or
> >
> >
> >>legally privileged, and is intended solely for the use of
the
> >>
> >>
> >individual
> >
> >
> >>or entity named in this message. If you are not the
intended
> >>
> >>
> >recipient,
> >
> >
> >>and have received this message in error, please immediately
> return
> >>
> >>
> >this
> >
> >
> >>by email and then delete it.
> >>
>
>>---------------------------------------------------------------------
> >>To unsubscribe, e-mail: [EMAIL PROTECTED]
> >>For additional commands, e-mail: [EMAIL PROTECTED]
> >>
> >>
> >>
> >>
>
>_______________________________________________________________________
> >
> >
> >>Notice: This email message, together with any attachments,
may
> >>
> >>
> >contain
> >
> >
> >>information of BEA Systems, Inc., its subsidiaries and
> >>
> >>
> >affiliated
> >
> >
> >>entities, that may be confidential, proprietary, copyrighted
> >>
> >>
> >and/or
> >
> >
> >>legally privileged, and is intended solely for the use of
the
> >>
> >>
> >individual
> >
> >
> >>or entity named in this message. If you are not the
intended
> >>
> >>
> >recipient,
> >
> >
> >>and have received this message in error, please immediately
> return
> >>
> >>
> >this
> >
> >
> >>by email and then delete it.
> >>
>
>>---------------------------------------------------------------------
> >>To unsubscribe, e-mail: [EMAIL PROTECTED]
> >>For additional commands, e-mail: [EMAIL PROTECTED]
> >>
> >>
> >
>
>_______________________________________________________________________
> >Notice: This email message, together with any attachments,
may
> contain
> >information of BEA Systems, Inc., its subsidiaries and
affiliated
> >entities, that may be confidential, proprietary, copyrighted
> and/or
> >legally privileged, and is intended solely for the use of the
individual
> >or entity named in this message. If you are not the intended
recipient,
> >and have received this message in error, please immediately return
this
> >by email and then delete it.
> >
> >---------------------------------------------------------------------
> >To unsubscribe, e-mail: [EMAIL PROTECTED]
> >For additional commands, e-mail: [EMAIL PROTECTED]
> >
> >
> >
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
_______________________________________________________________________
Notice: This email message, together with any attachments, may contain
information of BEA Systems, Inc., its subsidiaries and affiliated
entities, that may be confidential, proprietary, copyrighted and/or
legally privileged, and is intended solely for the use of the individual
or entity named in this message. If you are not the intended recipient,
and have received this message in error, please immediately return this
by email and then delete it.
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
