Removing attribute xsi:nil=true

chandra_perni · May 21st, 2009, 04:10 AM

I have a requirement where i need to remove the empty elements and the elements with attribute xsi:nil=' true" in my received xml.

My expected input format:
===================
<emp xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<emp2 sno='2'>
<name>Vijay</name>
<country>Australia</country>
<company/>
<dept>
<deptno>1</deptno>
<deptname>RND</deptname>
</dept>
</emp2>
<emp1 sno='3'>
<name>Chandra</name>
<country>India</country>
<company>B</company>
<dept>
<deptno xsi:nil="true"/>
<deptname>Dev</deptname>
</dept>
</emp1>
</emp>

My desired output:
==============
<?xml version = '1.0' encoding = 'UTF-8'?>
<emp xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<emp2 sno="2">
<name>Vijay</name>
<country>Australia</country>
<dept>
<deptno>1</deptno>
<deptname>RND</deptname>
</dept>
</emp2>
<emp1 sno="3">
<name>Chandra</name>
<country>India</country>
<company>B</company>
<dept>
<deptname>Dev</deptname>
</dept>
</emp1>
</emp>

My xsl code:
===========
<xsl:template match="@*|node()">
<xsl:if test=". != '' or ./@* != '' or ./@xsi:nil='true'">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:if>
</xsl:template>

Current output:
============
<?xml version = '1.0' encoding = 'UTF-8'?>
<emp xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<emp2 sno="2">
<name>Vijay</name>
<country>Australia</country>
<dept>
<deptno>1</deptno>
<deptname>RND</deptname>
</dept>
</emp2>
<emp1 sno="3">
<name>Chandra</name>
<country>India</country>
<company>B</company>
<dept>
<deptno xsi:nil="true"/>
<deptname>Dev</deptname>
</dept>
</emp1>
</emp>

Can anyone help me to get rid of the element with xsi:nil in the payload.

joefawcett · May 21st, 2009, 04:22 AM

Shouldn't your test be

Code:

not(xsi:nil = 'true')

as you said you want to copy if it's not nil?
I'm not sure why you have the

Code:

./@* != ''

part, that doesn't seem to be in the requirement. Why not

Code:

. =!= '' or not(xsi:nil = 'true')

?

mhkay · May 21st, 2009, 04:25 AM

Rather than having a single template rule with an xsl:if inside it, use multiple template rules. That's what rule-based programming is about.

Then you just need the rule

<xsl:template match="*[@xsi:nil='true']"/>

to get rid of these elements.

Your existing logic is flawed. You're copying elements if xsi:nil is true, whereas you want to do the opposite. And the condition (./@* != '' or ./@xsi:nil='true') doesn't make any sense, because if @xsi:nil="true" is true, then the first condition @* != '' will also be true - it tests whether there is at least one attribute whose value is non-empty.

mrame · May 21st, 2009, 04:38 AM

Try this:

Code:

<xsl:template match="*">
<xsl:if test=". != ''">
<xsl:copy>
<xsl:copy-of select="@*"/>
<xsl:apply-templates></xsl:apply-templates>
</xsl:copy>
</xsl:if>
</xsl:template>

<xsl:template match="*[@xsi:nil='true']"/>

chandra_perni · May 21st, 2009, 04:46 AM

Hi joefawcett i added this condition ./@* != '' because i may have other elements with attributes which should not be removed. I haven't mentioned it in the above requirement. Yes my condition is wrong.

Thanks mhkay i am trying that multiple template rule approach

chandra_perni · May 21st, 2009, 04:59 AM

Hi mrame sorry i havent seen ur message. Yes it works for me Thanks Michael and Rummy. But i have a doubt here we used two templates. If the element is not null we are copying it and the apply templates is called and it will call the other template before the copy is completed in which it will remove the xsi:nil? Is this correct?

mhkay · May 21st, 2009, 05:10 AM

>If the element is not null we are copying it and the apply templates is called and it will call the other template before the copy is completed in which it will remove the xsi:nil?

I'm not sure quite what you mean. I think you haven't fully understood template rules. When you select nodes in apply-templates, each node is processed by one template rule, the one whose pattern is the best match. So if xsl:nil='true' it will choose the empty template rule (effectively deleting the element), otherwise it will choose the identity template rule (effectively copying the element).

chandra_perni · May 21st, 2009, 05:29 AM

Thanks Michael i got it now.

fixit · September 2nd, 2009, 12:00 PM

I get an error indicating "invalid prefix error in xpath expression, invaid prefix" in xmlspy when I apply this xsl. The part

Code:

match="*[@xsi:nil='true']"

is highlighted. My complete xsl follows. Please advise. I simply want to remove all elements with the xsl:nil attribute. Thanks.

Code:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format">
	<xsl:template match="@* | node()">
 <xsl:copy>
   <xsl:apply-templates select="@* | node()"/>
 </xsl:copy>
</xsl:template>


<xsl:template match="*[@xsi:nil='true']"/>

</xsl:stylesheet>

samjudson · September 2nd, 2009, 12:04 PM

where are you declaring the xsi namespace prefix?