Extracting the attributes when the occurance of them is not particular - xslt

Question

I am working on the extracting the values background color and width attributes from "td" of a table.
There are several ways of occurance of Back ground color and width. T
I have following set of valid elements.
1.<td style="BACKGROUND-COLOR: yellow; WIDTH: 52%"></td>
(combination of BACKGROUND-COLOR and Width in one order)
2.<td style="WIDTH: 52%;BACKGROUND-COLOR: green"></td>
(combination of BACKGROUND-COLOR and Width in another order)
3.<td style="WIDTH:52%;BACKGROUND-COLOR: green"></td>
(Spaces could vary from ":" and value)
4.<td style="BACKGROUND-COLOR: gray"></td>
(only BACKGROUND-COLOR in style)
5.<td style="BACKGROUND-COLOR: Gray"></td>
(Value of BACKGROUND-COLOR can be case sensitive)
6.<td style="BACKGROUND-COLOR: #ffff00"></td>
(value of BACKGROUND-COLOR can be hexadecimal also)
7.<td bgcolor="#008000" style="WIDTH: 54%">
(BACKGROUND-COLOR can occur as bgcolr also(hexadecimal code)
8.<td bgcolor="yellow">
(BACKGROUND-COLOR can occur as bgcolr also(string))
List of valid colors and their codes:(all the values are case sensitive)
Yellow:#ffff00
Gray:#808080
Green:#008000
Output:
1.<bgclr>Yellow</bgclr>
<colwidth>52</colwidth>
2.<bgclr>Green</bgclr>
<colwidth>52</colwidth>
3. <bgclr>Green</bgclr>
<colwidth>52</colwidth>
4.<bgclr>Gray</bgclr>
5.<bgclr>Gray</bgclr>
6.<bgclr>Yellow</bgclr>
7.<bgclr>Green</bgclr>
<colwidth>54</colwidth>
8.<bgclr>Yellow</bgclr>
I have tried my level best to solve this, and it looks complicated for me.
I am also providing the valid xml file.
<tr>
<td style="BACKGROUND-COLOR: yellow; WIDTH: 52%"></td>
<td style="WIDTH: 52%;BACKGROUND-COLOR: green"></td>
<td style="WIDTH:52%;BACKGROUND-COLOR: green"></td>
<td style="BACKGROUND-COLOR: gray"></td>
<td style="BACKGROUND-COLOR: Gray"></td>
<td style="BACKGROUND-COLOR: #ffff00"></td>
<td bgcolor="#008000" style="WIDTH: 54%"></td>
<td bgcolor="yellow"></td>
</tr>
Can any one help on this.
Thanks.

Answer 1

We can leverage the power of xsl:apply-templates and predicates to avoid a lot of painful xsl:choose statements. A template approach will also give us a more modular solution.
This XSLT 1.0 style-sheet ...
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes"/>
<xsl:variable name="lowercase" select="'abcdefghijklmnopqrstuvwxyz'" />
<xsl:variable name="uppercase" select="'ABCDEFGHIJKLMNOPQRSTUVWXYZ'" />
<xsl:template match="/">
<tr>
<xsl:apply-templates select="*/td"/>
</tr>
</xsl:template>
<xsl:template match="td">
<td>
<xsl:apply-templates
select="self::*[contains(#style,'BACKGROUND-COLOR:') or #bgcolor]"
mode="bg-colour"/>
<xsl:apply-templates
select="self::*[contains(#style,'WIDTH:')]"
mode="width"/>
</td>
</xsl:template>
<xsl:template match="td[#bgcolor]" mode="bg-colour">
<xsl:call-template name="render-bg-colour">
<xsl:with-param name="raw-colour" select="#bgcolor" />
</xsl:call-template>
</xsl:template>
<xsl:template match="td" mode="bg-colour">
<xsl:call-template name="render-bg-colour">
<xsl:with-param name="raw-colour" select="
substring-before( substring-after(concat(#style,';'),'BACKGROUND-COLOR:'), ';')" />
</xsl:call-template>
</xsl:template>
<xsl:variable name="palette">
<colours>
<colour>
<code>#ffff00</code>
<name>Yellow</name>
</colour>
<colour>
<code>#808080</code>
<name>Gray</name>
</colour>
<colour>
<code>#008000</code>
<name>Green</name>
</colour>
</colours>
</xsl:variable>
<xsl:template name="render-bg-colour">
<xsl:param name="raw-colour" />
<xsl:variable name="trim-colour" select="normalize-space( $raw-colour)" />
<xsl:variable name="canon-colour" select="
document('')//xsl:variable[#name='palette']/colours/colour[
(translate($trim-colour, $uppercase, $lowercase) =
translate(name , $uppercase, $lowercase) ) or
($raw-colour = code)
]/name/text()"/>
<bgclr>
<xsl:value-of select="$canon-colour" />
</bgclr>
</xsl:template>
<xsl:template match="td" mode="width">
<colwidth>
<xsl:value-of select="
normalize-space( substring-before( substring-after(#style,'WIDTH:'), '%'))" />
</colwidth>
</xsl:template>
</xsl:stylesheet>
... when applied to this input document ...
<tr>
<td style="BACKGROUND-COLOR: yellow; WIDTH: 52%"></td>
<td style="WIDTH: 52%;BACKGROUND-COLOR: green"></td>
<td style="WIDTH:52%;BACKGROUND-COLOR: green"></td>
<td style="BACKGROUND-COLOR: gray"></td>
<td style="BACKGROUND-COLOR: Gray"></td>
<td style="BACKGROUND-COLOR: #ffff00"></td>
<td bgcolor="#008000" style="WIDTH: 54%"></td>
<td bgcolor="yellow"></td>
</tr>
... will yield this output document...
<tr>
<td>
<bgclr>Yellow</bgclr>
<colwidth>52</colwidth>
</td>
<td>
<bgclr>Green</bgclr>
<colwidth>52</colwidth>
</td>
<td>
<bgclr>Green</bgclr>
<colwidth>52</colwidth>
</td>
<td>
<bgclr>Gray</bgclr>
</td>
<td>
<bgclr>Gray</bgclr>
</td>
<td>
<bgclr>Yellow</bgclr>
</td>
<td>
<bgclr>Green</bgclr>
<colwidth>54</colwidth>
</td>
<td>
<bgclr>Yellow</bgclr>
</td>
</tr>