Functions Returning null when called twice?

Aygith · September 2nd, 2013, 04:43 AM

I have a function as follows

Code:

<xsl:function name="fns:getClassft" as="xs:string">
	<xsl:param name="root" as="xs:string"/>
	<xsl:choose>
		<xsl:when test="$root = 'F'">F</xsl:when>
		<xsl:when test="$root = 'H'">H</xsl:when>
		<xsl:when test="$root = 'O'">I</xsl:when>
		<xsl:when test="$root = 'P'">C</xsl:when>
		<xsl:when test="$root = 'R'">R</xsl:when>
		<xsl:when test="$root = 'S'">S</xsl:when>
		<xsl:when test="$root = 'U'">U</xsl:when>
		<xsl:otherwise>E</xsl:otherwise>																										
	</xsl:choose>
</xsl:function>

This is called using the following;

Code:

<xsl:value-of select="fns:getClassft($simple/proposerclassft)"/>

when in the input xml this field appears twice, the function returns a null and causes the entire transform to fall over.

Code:

<proposerclassft>R</proposerclassft>
<proposerclassft>R</proposerclassft>

If i remove one of the above, it works fine.

Any idea why this is causing the function/transform to stop dead when called?
is there some extra code needed to handle this null and cause it to output the otherwise when a null occurs?
Usually there would not ever be a duplicated field in the XML but i need the transform to be defensively built to not fall over if one were to occur.
Below is a snipper of the transform and the end section (where it fall over) of the xml produced.
Transform;

Code:

&lt;Occupation&gt;
	&lt;Occupation_Code Val='<xsl:value-of select="$simple/proposerocccodeft" />' /&gt;
	&lt;Occupation_EmploymentType Val='<xsl:value-of select="fns:getClassft($simple/proposerclassft)"/>' /&gt;
	&lt;Occupation_EmployersBusiness Val='<xsl:value-of select="$simple/proposerempcodeft" />' /&gt;
	&lt;Occupation_FullTimeEmploymentInd Val='Y' /&gt;
&lt;/Occupation&gt;

Output XML;

Code:

&lt;Occupation&gt
       &lt;Occupation_Code Val='R09' /&gt;
       &lt;Occupation_EmploymentType Val='</xrt:RequestXML></ns:messageIn></ns:ProcessTran></soapenv:Body></soapenv:Envelope>

mhkay · September 2nd, 2013, 05:47 AM

Firstly, there's no such thing as "null" in the XPath data model. What was the actual error message?

Secondly, when you do this

Code:

<xsl:value-of select="fns:getClassft($simple/proposerclassft)"/>

then the function is not called twice, it is called once with a sequence of two element nodes as the argument. That's an error because the function signature says that it expects a single string to be supplied.

Aygith · September 2nd, 2013, 06:00 AM

Hi Michael,

Ahh apologies for thta, the test harness i am using just says "null" and stops the xml output at that point, the error is obviously as you have said; that the call for the function is supplying both of the fields in as a argument,

My understanding was that it would call the function for each time it found the field ($simple/proposerclassft). is there a way to set the "call" to only supply the firts case it finds of the field? i.e $simple/proposerclassft[1] , i have used something similar with DateTimes before but not sure if this will work with Functions?

Martin Honnen · September 2nd, 2013, 06:04 AM

If you want to call the function for each selected node use

Code:

$simple/proposerclassft/fns:getClassft(.)

if you want to call it only for the first select node use

Code:

fns:getClassft(($simple/proposerclassft)[1])

Aygith · September 2nd, 2013, 06:12 AM

Thanks Martin,

I thought it would be a matter of putting a Position perameter into the function call. that appears to have corrected the issue.

Thanks again to you both!

samjudson · September 2nd, 2013, 06:56 AM

Yes, because you are calling a function which states it takes a string with a sequence instead.

Try simply doing fns:getClassft($simple/proposerclassft[1]) if you are happy to skip anything but the first element in the sequence.