XSL Notes Page 1

XSL Consists of 3 parts
1. XSLT (Language for transforming XML documents)
2. XPath (Language for defining parts of XML documents)
3. XSL (Vocabulary for formatting XML documents)
XSL Languages
- XSLT and XPath
  
  XSLT is used to transform an XML document into another XML document, or
  
  into a type of document recognized by browsers eg.XHTML
  
  XSLT can also add/remove elements rearrange/sort elements, and
  
  Test/make decisions about which elements to display
  
  XSL uses XSLT to transform an XML source tree into an XML result tree
  
  During Transformation XSLT Uses XPath to define parts of the source
  
  document that match one or more predefined Templates.
  
  When a match is found XSLT will transform the matching part of the
  
  Source document into a Result document
Browsers
- IE 5 is not 100% compatable with XSL
- NetScape isn't either
- IE 6 should be ok

XSL - Transformation (XSLT)

Requires Style Sheet Declaration

<xsl:stylesheet version - "1.0" xmlns:xsl = "http://www.w3.org.1999/XSL/Transform">

OR

<xsl:transform version = "1.0" xmlns:xsl = "http://www.w3.org.1999/XSL/Transform">

FOR I.E. 5 Use

<xsl:stylesheet xmlns:xsl = "http://www.w3.org/TR/WD-xsl">

Steps for Transformation

Start with an XML file

Example:

                    <?xml version = "1.0" encoding = "ISO-8859-1"?>
                    <catalog>
                      <cd>
                        <title>Empire Burlesque</title>
                        <artist>Bob Dylan</artist>
                        <country>USA</country>
                        <price>10.90</price>
                        <year>1985</year>
                      </cd>
                    </catalog>

Create an XSL file for it

Example:

                    <?xml version = "1.0" encoding = "ISO-8859-1"?>
                    <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
                      <xsl:template match = "/">
                        <html>
                          <body>
                            <h2>My CD Colletion</h2>
                            <table border = "1">
                              <tr bgcolor = "blue">
                                <th align = "left>Title</th>
                                <th align = "left>Artist</th>
                              <tr>
                              <xsl:for-each select = "catalog/cd">
                              <tr>
                                <td><xsl:value-of select = "title" /></td>
                                <td><xsl:value-of select = "artist" /></td>
                              </tr>
                              </xsl:for-each>
                            </table>
                          </body>
                        </html>
                      </xsl:template>
                    </xsl:stylesheet>

Link them by adding a reference
to the XSL file inside the XML file.

Example:

                    <?xml version = "1.0" encoding = "ISO-8859-1"?>
                    <?xml-stylesheet type = "text/xsl" href = "cdcatalog.xsl"
                    <catalog>
                      <cd>
                        <title>Empire Burlesque</title>
                        <artist>Bob Dylan</artist>
                        <country>USA</country>
                        <price>10.90</price>
                        <year>1985</year>
                      </cd>
                    </catalog>

The <xsl:template> Element

XSL style sheets contain template elements that hold the rules to apply

when a specified node is matched

The match Attribute

Example:

              <?xml version = "1.0" encoding = "ISO-8859-1"?>
              <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
              <xsl:template match = "/">
              <html>
                <body>
                  <h2>My CD Colletion</h2>
                  <table border = "1">
                    <tr bgcolor = "blue">
                      <th align = "left>Title</th>
                      <th align = "left>Artist</th>
                    <tr>
                    <xsl:for-each select = "catalog/cd">
                    <tr>
                      <td><xsl:value-of select = "title" /></td>
                      <td><xsl:value-of select = "artist" /></td>
                    </tr>
                    </xsl:for-each>
                  </table>
                </body>
              </html>
              </xsl:template>
              </xsl:stylesheet>

The match = "[match]" Attribute is used to associate the template with an XML element.

The match attribute can also be used to define a template for a whole branch of the

XML document. eg; match = "/" defines the whole document

The <xsl:value-of> Element

Used to Select the Value of an XML Element and add it

To the OutPut Stream of the Transformation

Example:

            <?xml version = "1.0" encoding = "ISO-8859-1"?>
            <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
              <xsl:template match = "/">
                <html>
                  <body>
                    <h2>My CD Colletion</h2>
                    <table border = "1">
                      <tr bgcolor = "blue">
                        <th align = "left>Title</th>
                        <th align = "left>Artist</th>
                      <tr>
                      <tr>
                        <td><xsl:value-of select = "catalog/cd/title" /></td>
                        <td><xsl:value-of select = "catalog/cd/artist" /></td>
                      </tr>
                    </table>
                  </body>
                </html>
              </xsl:template>
            </xsl:stylesheet>

The value of the required select attribute contains an XPath experession

which resembles navaigating a file system where "/" selects a subdirectory"

The XSL <for-each> Element

Used to Select every XML Element of a node set

Example:

            <?xml version = "1.0" encoding = "ISO-8859-1"?>
            <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
              <xsl:template match = "/">
                <html>
                  <body>
                    <h2>My CD Colletion</h2>
                    <table border = "1">
                      <tr bgcolor = "blue">
                        <th align = "left>Title</th>
                        <th align = "left>Artist</th>
                      <tr>
                      <xsl:for-each select = "catalog/cd">
                        <tr>
                          <td><xsl:value-of select = "title" /></td>
                          <td><xsl:value-of select = "artist" /></td>
                        </tr>
                      </xsl:for-each>
                    </table>
                  </body>
                </html>
              </xsl:template>
            </xsl:stylesheet>

The value of the required select attribute contains an XPath experession

which resembles navaigating a file system where "/" selects a subdirectory"

The XSL <sort> Element

Used to Sort the XML Elements of a node set

Example:

          <?xml version = "1.0" encoding = "ISO-8859-1"?>
          <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
            <xsl:template match = "/">
              <html>
                <body>
                  <h2>My CD Colletion</h2>
                  <table border = "1">
                    <tr bgcolor = "blue">
                      <th align = "left>Title</th>
                      <th align = "left>Artist</th>
                    <tr>
                    <xsl:for-each select = "catalog/cd">
                    <xsl:sort select = "artist" />
                      <tr>
                        <td><xsl:value-of select = "title" /></td>
                        <td><xsl:value-of select = "artist" /></td>
                      </tr>
                    </xsl:for-each>
                  </table>
                </body>
              </html>
            </xsl:template>
          </xsl:stylesheet>

The value of the required select attribute contains an XPath experession

which resembles navaigating a file system where "/" selects a subdirectory"

If: The <xsl:if> Element

Used to Select the XML Elements of a node set

Only if a specified condition is true

Watch out for "&gt" to make ">" in the xsl file!

Example:

          <?xml version = "1.0" encoding = "ISO-8859-1"?>
          <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
            <xsl:template match = "/">
              <html>
                <body>
                  <h2>My CD Colletion</h2>
                  <table border = "1">
                    <tr bgcolor = "blue">
                      <th align = "left>Title</th>
                      <th align = "left>Artist</th>
                    <tr>
                    <xsl:for-each select = "catalog/cd">
                      <xsl:if test = "price &gt; 10">
                        <tr>
                          <td><xsl:value-of select = "title" /></td>
                          <td><xsl:value-of select = "artist" /></td>
                        </tr>
                      </xsl:if>
                    </xsl:for-each>
                  </table>
                </body>
              </html>
            </xsl:template>
          </xsl:stylesheet>

If the price > 10 then select the titles and artists

Choose: The <xsl:choose> Element

Used to express multiple conditional tests Using

<xsl:choose>

<xsl:when>

<xsl:otherwise>

Example:

          <?xml version = "1.0" encoding = "ISO-8859-1"?>
          <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
            <xsl:template match = "/">
              <html>
                <body>
                  <h2>My CD Colletion</h2>
                  <table border = "1">
                    <tr bgcolor = "blue">
                      <th align = "left>Title</th>
                      <th align = "left>Artist</th>
                    <tr>
                    <xsl:for-each select = "catalog/cd">
                        <tr>
                          <td><xsl:value-of select = "title" /></td>
                            <xsl:choose>
                              <xsl:when test = "price &gt; 10">
                                <td bgcolor = "pink"><xsl:value-of select = "artist" /></td>
                              </xsl:when>
                              <xsl:otherwise>
                                <td><xsl:value-of select = "artist" /></td>
                              </xsl:otherwise>
                            </xsl:choose>
                        </tr>
                    </xsl:for-each>
                  </table>
                </body>
              </html>
            </xsl:template>
          </xsl:stylesheet>

The above code will add a pink background to the artist column when price > 10

Apply-Templates: The <xsl:apply-templates> Element

Applies a template rule to the current element or it's childNodes

Add a select attribute to the <xsl:apply-templates> element to process

Example:

          <?xml version = "1.0" encoding = "ISO-8859-1"?>
          <xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
            <xsl:template match = "/">
              <html>
                <body>
                  <h2>My CD Colletion</h2>
                  </xsl:apply-templates>
                </body>
              </html>
            </xsl:template>

              <xsl:template match = "cd">
                <p>
                  <xsl:apply-templates select = "title" />
                  <xsl:apply-templates select = "artist" />
                </p>
              </xsl:template>

              <xsl:template match = "title">
                Title: <span style = "color:red"><xsl:value-of select = "," /></span><br />
              </xsl:template>

              <xsl:template match = "artist">
                Artist: <span style = "color:blue"><xsl:value-of select = "," /></span><br />
              </xsl:template>

          </xsl:stylesheet>

On the Client

Use JavaScript to do browser specific testing for different style sheets
Leave out the XML reference to the XSL file, then load it on the broswer

Example:

          <html>
            <body>
              <script type = "text/javascript">

                // Load XML
                   var xml = new ActiveXObject("Microsoft.XMLDOM")
                   xml.async = false
                   xml.load("filename.xml")

                // Load XSL
                   var xsl = new ActiveXObject("Microsoft.XMLDOM")
                   xsl.async = false
                   xsl.load("filenae.xsl")

                // Transform
                   document.write(xml.transformNode(xsl))

              </script>
            </body>
          </html>

On the Server

Transform the XML to XHTML on the Server

Example: ASP

              <$
               ' Load XML
                 set xml = Server.CreateObject("Microsoft.XMLDOM")
                 xml.async = false
                 xml.load(Server.MapPath("filename.xml"))

                ' Load XSL
                  set xsl = Server.CreateObject("Microsoft.XMLDOM")
                  xsl.async = false
                  xsl.load(Server.MapPath("filename.xsl"))

                ' Transform
                  Response.Write(xml.transformNode(xsl))
              %>

XSLT Elements

Element	Description
xsl:apply-imports	Applies a template rule from an imported style sheet
xsl:apply-templates	Applies a template rule to the current element or to the current element's childNodes
xsl:attribute	Adds an attribute
xsl:attribute-set	Defines a named set of Attributes
xsl:call-template	Calls a Named Template
xsl:choose	Expresses multiple condition tests
xsl:comment	Creates a comment node in the result tree
xsl:copy	Creates a copy of the current node with childNodes and attributes
xsl:copy-of	Creates a copy of the current node with childNodes and attributes
xsl:decimal-format	Defines the characters and symbols to be used when converting numbers into strings with the format-number() function
xsl:element	Creates an element node in the output document
xsl:fallback	Specifies an alternate code to run if the XSL processor doesn't support an element
xsl:for-each	for loop
xsl:if	If statement
xsl:import	Imports the contents of one style sheet into another
xsl:include	Includes the contents of one style sheet into another
xsl:key	Declares a Named Key that can be used in the style sheet with the key() function
xsl:message	Writes a message to the output (error reporting)
xsl:namespace-alias	Replaces a namespace in the style sheet to a different NameSpace in the output
xsl:number	Determines the integer position of the current node and formats a number
xsl:otherwise	The otherwise part of choose
xsl:output	Defines the format of the output document
xsl:param	Declares a local or global parameter
xsl:preserve-space	Defines the elements for which white space should be preserved
xsl:processing-instruction	Writes a processing instruction to the output
xsl:sort	Sort Statement
xsl:strip-space	Defines the elements for which white space should be removed
xsl:stylesheet	Defines the root element of a style sheet
xsl:template	Rules to apply when a specified node is matched
xsl:text	Writes literal text to the output
xsl:transform	Defines the root element of a style sheet
xsl:value-of	Extracts the value of a selected node
xsl:variable	Declares a local or global variable
xsl:when	Specifies an action for the choose element
xsl:with-param	Defines the value of a parameter to be passed to a template

XSLT and Inherited XPath Functions

XSLT

Name	Description
current()	Returns the current Node
document()	Used to access the nodes in an external XML document
element-available()	Tests whether the element specified is supported by the XSLT processor
format-number()	Converts a number into a string
function-available()	Tests whether the Function Specified is supported by the XSLT Processor
generate-id()	Returns a String Identifier of a Specified Node
system-property()	Returns the value of the system properties
unparsed-entity-uri()	Returns the URI of an Unparsed Entity
key()	Returns a Node-Set using the Index Specified by an <xsl:key> element

Inherited XPath Functions

Node Set Functions

Name	Description
count()	Returns the number of nodes in a node-set	number = count(node-set)
id()	Selects Elements by Unique Id	node-set = id(value)
local-name()	Returns the local part of a node A Node usually consists of a prefix, a colon, and the local name	string = local-name(node)
name()	returns the name of a node	string = name(node)
position()	Returns the position of a Node in the Node-List	number = position()
last()	Returns the position of the last node in a node-list	number = last()
namespace-uri	Returns the namespaace URI of a specified node	uri = namespace-uri(node)

String Functions

Name	Description
concat()	string concatenation	string = concat(val1, val2,...)
contains()	Returns true or false if the second string is found in the first	bool = contains(string,substr)
normalize-space()	Removes leading/traline spcaes from a string	string = normalize-space(string)
starts-with()	Returns tre if the first string starts with the second	bool = starts-with(string,substr)
string()	Converts the value to a string	string(value)
string-length()	Number of characters in a string	number = string-length(string)
substring()	Returns a part of the string in the string argument	string = substring(string, start, length)
substring-after()	Returns the part of the string in string argument that occurs after the substring in the substr argument	string = substring-after(string, substr)
substring-before()	Returns the part of the string in the string argument that occurs before the substring in the substr argument	string = substring-before(string, substr)
translate()	Takes the value arguemtn and replaces all occurances of string1 with string2 and returns the modified string	string = translate(value, string1, string2)

Number Functions

Name	Description
ceiling()	Returns the smallest integer that is not less than the number argument	number = ceiling(number)
floor()	Returns the largest integer that is not greater than the number argument	number = floor(number)
number()	converts to a number	number = number(value)
round()	rounds to the nearest integer	integer = round(number)
sum()	total of a set of numeric values in a node-set	number = sum(nodeset)

Boolean Functions

Name	Description
boolean()	Converts the value to Boolean and returns true or false	bool = boolean(value)
false()	Returns false	false()
lang()	Returns true if the language argument matches the language of the <xsl:lang> element, otherwise false	bool = lang(language)
not()	Returns true if the condition argument is false and false if the condition is true	bool = not(condition)
true()	Returns true	true()

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