using xslt and xpath

1Copyright (c) [2001]. Roger L. Costello. All Rights Reserved.

Using XSLT and XPath

Roger L. Costello (XML Technologies)

With changes and additions by Thomas Krichel http://openlib.org/home/krichel


Roger’s Acknowledgement

• I wish to thank David Jacobs for showing me a new way of looking at HTML and XSLT/XPath

• Many of the examples that I use in this tutorial come straight from David's excellent paper, Rescuing XSLT from Niche Status (see http://www.xfront.com)


Thomas acknowledgement

• Roger L. Costello

• Mitre Corp.


XSL transforms XML

• XSL may be used to generate either HTML, XML, or text

XSL Processor

XSL

XML HTML (or XML or text)


Doing it using Internet Explorer

• First, download the latest version of Internet Explorer (at this time it is 6.0)

• Write an XSL stylesheet stylish.xsl

• Write an XML file, and refer to the xsl stylesheet with a processing instruction

<?xml-stylesheet type="text/xsl“ href="stylish.xsl"?>

Note: this does not work with other browsers!


General stuff

Part 0


XML tree

• XSL has a model of XML as a tree.• XSL tree model is similar to the DOM model.• As the processor does its job it looks at elements

of the input tree and transforms them to the output tree.

• The processor only writes the file to the tree at the end.

• End points in the tree are called “nodes”.


in the general section

• we examine how XSL looks at an XML document. In fact it builds a tree.

• and then we look at a very simple way to look at what the stylesheet does. After that we have Roger showing us the details.


Seven types of nodes• root node: contains all the elements in the

document. Not to be confused with the document element of XML.

• element node: contains an element• text node: contain an as-large-as-possible area of

text.• attribute node: contains attribute name and value• comment node: contains a comment• processing instruction (p-i) node• namespace node: each element node has one

namespace node for every namespace declaration


properties of nodes: name

• This is empty for the root, text and comment nodes.

• for elments and attribute node, it is the name as it appears in the xml file, expanded by namespace declarations.

• for p-i nodes, it is the target

• for a namespace node, it is the prefix


properties of nodes: string value• for text nodes: the text • for comment nodes: the text of the

comment• for p-i nodes: the data part of the p-i.• for an attribute node: the value of the

attribute• for a root node: the concatenation of all the

string values of all element and text children.

• for a namespace node: the URI of the namespace


properties of nodes: base URI

• for all nodes: the URI of the XML source document where the node has been found

• Only of interest for elements and p-i nodes

• for the root node: the URI of the document

• for attribute, text and comment nodes: the base URI of its parent node


properties of nodes: children

• for element nodes: all the element nodes, text nodes, p-i nodes and comment nodes between its start and end tags.

• for root nodes: all the element nodes, text nodes, p-i nodes and comment nodes that are not children of some other node.


parent node

• for all nodes except root nodes: the parent of the node.

• attribute nodes and namespace nodes have an element node as parent node, but are not considered to be its child.


property of nodes: attribute

• element: one to many attributes that the element has

• other nodes: empty

Now we look at what XSL does


Different formats…

• <xsl:output method="xml"> is the default

• <xsl:output method="html>

• <xsl:output method="text"> used for everything else. Final formatting may be up to formatting objects, anyway.

• Your stylesheet processor may have more formats, but they will be vendor-specific.


templates set rules

<xsl:template match="expression">

do some stuff

<xsl:template>

This is a rule that says, if you find a node that matches the expression expression, then go ahead and do some stuff. It is called a template. The fact that a rule is written down down does not imply that it is applied.


applying templates

• <xsl:apply-templates/>

says: apply all template rules on the current node and on all its child nodes.


Default, built-in rules for the nodes

• root: <xsl:apply-templates> on all children

• element: <xsl:apply-templates> to the current node and all its children

• attribute: copy the value as text to the output

• text: copy the text to the output

• comment, p-i, namespace: do nothing


Generating HTML

part I


HTML Generation

• We will first use XSL to generate HTML documents• When generating HTML, XSL should be viewed as a

tool to enhance HTML documents.– That is, the HTML documents may be enhanced

by extracting data out of XML documents– XSL provides elements (tags) for extracting the

XML data, thus allowing us to enhance HTML documents with data from an XML document


Enhancing HTML Documents with XML Data

XML Document

HTML Document(with embeddedXSL elements)

XSL element

XML data

XSLProcessor

XML data


Enhancing HTML Documents with the Following XML Data

<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="FitnessCenter.xsl"?>

<FitnessCenter> <Member level="platinum"> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member></FitnessCenter>

FitnessCenter.xml


Embed HTML Document in an XSL Template

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

version="1.0"> <xsl:output method="html"/> <xsl:template match="/"> <HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY> Welcome! </BODY> </HTML> </xsl:template></xsl:stylesheet>

FitnessCenter.xsl (see html-example01)


Note

• The HTML is embedded within an XSL template, which is an XML document. The HTML must be well formed.

• We are able to add XSL elements to the HTML, allowing us to extract data out of XML documents.

• Let's customize the HTML welcome page by putting in the member's name. This is achieved by extracting the name from the XML document. We use an XSL element to do this.


Extracting the Member Name<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="html"/> <xsl:template match="/"> <HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY> Welcome <xsl:value-of select="/FitnessCenter/Member/Name"/>! </BODY> </HTML> </xsl:template></xsl:stylesheet>

(see html-example02)


Extracting a Value from & Navigating the XML Document

• Extracting values:

– use the <xsl:value-of select="…"/> XSL element

• Navigating:

– The slash ("/") indicates parent/child relationship

– A slash at the beginning of the path indicates that it is an absolute path, starting from the top of the XML document

/FitnessCenter/Member/Name

"Start from the top of the XML document, go to the FitnessCenter element, from there go to the Member element, and from there go to the Name element."


Document/

PI<?xml version=“1.0”?>

ElementFitnessCenter

ElementMember

ElementName

ElementPhone

ElementPhone

ElementFavoriteColor

TextJeff

Text555-1234

Text555-4321

Textlightgrey


Use FavoriteColor as the bgcolor<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="html"/> <xsl:template match="/"> <HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY bgcolor="{/FitnessCenter/Member/FavoriteColor}"> Welcome <xsl:value-of select="/FitnessCenter/Member/Name"/>! </BODY> </HTML> </xsl:template></xsl:stylesheet>



Using an extracted value as attribute

Attribute values cannot contain "<" nor ">" - Consequently, the following is NOT valid: <Body bgcolor="<xsl:value-of select='/FitnessCenter/Member/FavoriteColor'/>">

To extract the value of an XML element and use it as an attributevalue you must use curly braces: <Body bgcolor="{/FitnessCenter/Member/FavoriteColor}">

Evaluate the expression within the curly braces. Assign the valueto the attribute.


Extract the Home Phone Number<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="html"/> <xsl:template match="/"> <HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY bgcolor="{/FitnessCenter/Member/FavoriteColor}"> Welcome <xsl:value-of select="/FitnessCenter/Member/Name"/>! <BR/> Your home phone number is: <xsl:value-of select="/FitnessCenter/Member/Phone[@type='home']"/> </BODY> </HTML> </xsl:template></xsl:stylesheet>



The predicate

In this example we want "the Phone element where the valueof its type attribute equals 'home' ":

<xsl:value-of select="/FitnessCenter/Member/Phone[@type='home']"/>

The expression within […] is called a "predicate". Its purposeis to filter.

Note the use of the single quotes within the double quotes. select=" … ' …' …"


Review - HTML Table

<table border=“1” width=“100%”>

</table>

<tr>

<tr>

<tr> </tr>

</tr>

</tr><th> </th>

<th> </th>

<th> </th>

<td> </td>

<td> </td>

<td> </td>

<td> </td>

<td> </td>

<td> </td>

This will create a table with 3 rows - the first row contains a headerfor each column. The next two rows contains the table data.


<table border=“1” width=“75%”> <tr> <th>Fruit</th> <th>Color</th> </tr> <tr> <td>Papaya</td> <td>Red</td> </tr> <tr> <td>Banana</td> <td>Yellow</td> </tr></table>

Fruit Color

Papaya Red

Banana Yellow


Create a Table of Phone Numbers

• Suppose that a Member has an arbitrary number of phone numbers (home, work, cell, etc).

• Create an HTML table comprised of the phone numbers. On each row of the table put the type (home, work, cell, etc) in one column and the actual phone number in the next column.


<HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY bgcolor="{/FitnessCenter/Member/FavoriteColor}"> Welcome <xsl:value-of select="/FitnessCenter/Member/Name"/>! <BR/> Your phone numbers are: <TABLE border="1" width="25%"> <TR><TH>Type</TH><TH>Number</TH></TR> <xsl:for-each select="/FitnessCenter/Member/Phone"> <TR> <TD><xsl:value-of select="@type"/></TD> <TD><xsl:value-of select="."/></TD> </TR> </xsl:for-each> </TABLE> </BODY></HTML>


(leaving out xsl surroundings…)


Iterating through XML Elements

<xsl:for-each select="/FitnessCenter/Member/Phone">

<!- - Within here we are at one of the Phone elements. Thus, in <xsl:value-of select="path", the value for path is relative to where we are in the XML document. The "." refers to the Phone element that we are currently positioned at. - ->

</xsl:for-each>


Absolute Path versus Relative Path

<xsl:value-of select="/FitnessCenter/Member/Phone[@type='home']"/>

This is an absolute xPath expression(we start from the top of the XML treeand navigate down the tree)

<xsl:value-of select="@type"/>

This is a relative xPath expression(relative to where we currently are located, give me the value of thetype attribute)

Do Lab1,Parts 1-3


<HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY bgcolor="{/FitnessCenter/Member/FavoriteColor}"> Welcome <xsl:value-of select="/FitnessCenter/Member/Name"/>! <BR/> Your phone numbers are: <TABLE border="1" width="25%"> <TR><TH>Name</TH><TH>Type</TH><TH>Number</TH></TR> <xsl:for-each select="/FitnessCenter/Member/Phone"> <TR> <TD><xsl:value-of select="../Name"/></TD> <TD><xsl:value-of select="@type"/></TD> <TD><xsl:value-of select="."/></TD> </TR> </xsl:for-each> </TABLE> </BODY> </HTML>


Adding the name


Getting the Name when accessing the Phone

Member

Phone

555-1234

Phone

555-4321

Name

Jeff

Notice how when in the for-eachloop we need to accessthe Name which is "upand over" with respect to the Phone element

Bottom line: we can access elements in other parts of the XML tree via the “../” operator.


Conditional Processing

• Let's further enhance our example to provide a special offer to "platinum" members.

• We need to check to see if the "level" attribute on the Member element equals "platinum".

• Use the <xsl:if test="…"/> element to perform conditional processing.

Do Lab1,Part 4


<HTML> <HEAD> <TITLE>Welcome</TITLE> </HEAD> <BODY bgcolor="{/FitnessCenter/Member/FavoriteColor}"> Welcome <xsl:value-of select="/FitnessCenter/Member/Name"/>! <BR/> <xsl:if test="/FitnessCenter/Member/@level='platinum'"> Our special offer to platinum members today is ... <BR/> </xsl:if> Your phone numbers are: </BODY></HTML>


Adding the special offer, leaving phone numbers


Accessing Multiple Parts of the XML Document

• Let's enhance the table to contain three columns - the name of the Member, the type of the phone (home, work, cell, etc), and the actual phone number.

• Let us enlarge our document to contain a couple of more members.


<?xml version="1.0"?><FitnessCenter> <Member id="1" level="platinum"> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> <Member id="2" level="gold"> <Name>David</Name> <Phone type="home">383-1234</Phone> <Phone type="work">383-4321</Phone> <FavoriteColor>lightblue</FavoriteColor> </Member> <Member id="3" level="platinum"> <Name>Roger</Name> <Phone type="home">888-1234</Phone> <Phone type="work">888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> </Member></FitnessCenter>


Access repeated XML elements

<xsl:value-of select="/FitnessCenter/Member[1]/Name"/>"Select the Name of the first Member"

<xsl:value-of select="/FitnessCenter/Member[position()=1]/Name"/>"Select the Name of the first Member"

<xsl:value-of select="/FitnessCenter/Member[last()]/Name"/>"Select the Name of the last Member"

<xsl:for-each select="/FitnessCenter/Member[not(position()=last())]"> <!- - Process all Members but the last - -></xsl:for-each>


<xsl:for-each select="/FitnessCenter/Member[position() != last()]"> <!- - Process all Members but the last - -></xsl:for-each>

<xsl:for-each select="/FitnessCenter/Member[position() >1]"> <!- - Process all Members but the first - -></xsl:for-each>

<xsl:for-each select="/FitnessCenter//Name"> <!- - Process all Name elements which have FitnessCenter as an ancestor - -></xsl:for-each>

Access repeated XML elements


Review - HTML Hyperlinking

<A name="AnnaAndTheKing"></A>

…

<A href="#AnnaAndTheKing">Click Here</A>...

This creates an internal hyperlink (the source "anchor" links tothe target anchor).


Hyperlink Name to Home Phone

• Problem: create an HTML document that has two tables - a Member Name table, and a Member home Phone number table.

• Hyperlink the Member's Name to his/her Phone.


<TABLE border="1" width="25%"> <TR><TH>Name</TH></TR> <xsl:for-each select="/FitnessCenter/Member"> <TR><TD> <A href="#{@id}"> <xsl:value-of select="Name"/> </A> </TD></TR> </xsl:for-each> </TABLE> <BR/><BR/><BR/><BR/><BR/> <TABLE border="1" width="25%"> <TR><TH>Home Phone Number</TH></TR> <xsl:for-each select="/FitnessCenter/Member"> <TR><TD> <A name="{@id}"> <xsl:value-of select="Phone[@type='home']"/> </A> </TD></TR> </xsl:for-each> </TABLE> Do Lab1,

Parts 5-6


Numbering

• There is an XSL element that returns a number corresponding to the element's position in the set of selected nodes


<xsl:for-each select="/FitnessCenter/Member"> <xsl:number value="position()" format="1"/> <xsl:text>. </xsl:text> <xsl:value-of select="Name"/> <BR/></xsl:for-each>

Output:1. Jeff2. David3. Roger


Start Numbering from 0

• How would you start the numbering from zero, rather than one?

<xsl:number value="position() - 1" format="1">


format attribute of xsl:number

• In the previous example we saw how to generate numbers, and we saw that the generated numbers were 1, 2, 3, etc.

• With the format attribute we can specify the format of the generated number, i.e., 1, 2, 3 or I, II, III, or A, B, C, or …

– format=“1” generates the sequence: 1, 2, 3, …

– format=“01” generates: 01, 02, 03, …

– format=“A” generates: A, B, C, …

– format=“a” generates: a, b, c, …

– format=“I” generates: I, II, III, …

– format=“i” generates: i, ii, iii, ...


format attribute of xsl:number

<xsl:for-each select="/FitnessCenter/Member"> <xsl:number value="position()" format="A"/> <xsl:text>. </xsl:text> <xsl:value-of select="Name"/> <BR/></xsl:for-each>

Output:A. JeffB. DavidC. Roger


Sorting

• There is an XSL element that sorts the elements that you extract from the XML document

<xsl:for-each select="/FitnessCenter/Member"> <xsl:sort select="Name" order="ascending"/> <xsl:value-of select="Name"/> <BR/></xsl:for-each>

"For each Member, sort the Name elements"

Output:DavidJeffRoger



xsl:sort

<xsl:for-each select="/FitnessCenter/Member"> <xsl:sort select="Name" order="ascending"/> <xsl:value-of select="Name"/> <BR/></xsl:for-each>

The set of Member elements selected by xsl:for-each issorted using the Name child element. This occurs priorto the first iteration of the loop. After the set of Memberelements are sorted then the looping begins.


xsl:variable

• This XSL element allows you to create a variable to hold a value (which could be a string or a subtree of the XML document).

• The variable is referenced by $variable-name

<xsl:variable name=“hello” select=“'Hello World'”/>

This creates a variable called hello, that has a value which is a literal string.We could use this variable as follows: Value = <xsl:value-of select=“$hello”/>This will output:Value = Hello World


Member's Phone Numbers: <TABLE border="1" width="25%"> <TR><TH>Name</TH><TH>Type</TH><TH>Number</TH></TR> <xsl:for-each select="/FitnessCenter/Member"> <xsl:variable name="name" select="Name"/> <xsl:for-each select="Phone"> <TR> <TD><xsl:value-of select="$name"/></TD> <TD><xsl:value-of select="@type"/></TD> <TD><xsl:value-of select="."/></TD> </TR> </xsl:for-each> </xsl:for-each></TABLE>



xsl:variable

<xsl:variable name=“member” select=“Member[1]”/>

This creates a variable called member, that has a value which is a subtree.We could use this variable as follows: Name = <xsl:value-of select=“$member/Name”/>Home Phone = <xsl:value-of select=“$member/Phone[@type='home']”/>This will result in generating: Name = Jeff Home Phone = 555-1234

Member

Phone

555-1234

Phone

555-4321

Name

Jeff


concat() functionconcat(destination_string, string_to_add)

<xsl:for-each select="/FitnessCenter/Member">

<xsl:value-of select="concat('Welcome ', Name, '!')"/>

<BR/>

</xsl:for-each>

Output:

Welcome Jeff!

Welcome David!

Welcome Roger!


Scope of xsl:variable

• A variable is “write once, read many time”.

• A variable has a scope limited to the XSL element that it is nested within. Its scope starts where it is defined and extends to the end of the XSL element that it is nested within.


Member's Phone Numbers: <TABLE border="1" width="25%"> <TR><TD>Name</TD><TD>Type</TD><TD>Number</TD></TR> <xsl:for-each select="/FitnessCenter/Member"> <xsl:variable name="name" select="Name"/> <xsl:for-each select="Phone"> <TR> <TD><xsl:value-of select="$name"/></TD> <TD><xsl:value-of select="@type"/></TD> <TD><xsl:value-of select="."/></TD> </TR> </xsl:for-each> </xsl:for-each></TABLE>

The name variable's life ends hereDo Lab2,

Part 1


Global Variables<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="html"/> <xsl:variable name="pi" select="'3.142857142857'"/> <xsl:template match="/" > <HTML> <HEAD> <TITLE>Value of Pi</TITLE> </HEAD> <BODY> The value of pi = <xsl:value-of select="$pi"/> </BODY> </HTML> </xsl:template></xsl:stylesheet>


Problem• Suppose that we want to create a variable, names, and we want this

variable to contain a list of the Member Names, with each name separated by a slash. How would you create such a variable?

Here’s what you might attempt to do:

Member's Names:<xsl:variable name="names" select="/FitnessCenter/Member[1]/Name"/><xsl:for-each select="/FitnessCenter/Member[position() > 1]"> <xsl:variable name="names" select="concat($names, '/')"/> <xsl:variable name="names" select="concat($names, Name)"/> </xsl:for-each><xsl:value-of select="$names"/>

Output:

Jeff (see html-example13)


Let’s add some statements to trace this example

<xsl:variable name="names" select="/FitnessCenter/Member[1]/Name"/><xsl:value-of select="$names"/><BR/><xsl:for-each select="/FitnessCenter/Member[position() > 1]"> <xsl:variable name="names" select="concat($names, '/')"/> <xsl:value-of select="$names"/> <BR/> <xsl:variable name="names" select="concat($names, Name)"/> <xsl:value-of select="$names"/> <BR/> </xsl:for-each> <xsl:value-of select="$names"/>



Output of the previous example

Jeff

Jeff/

Jeff/David

Jeff/ The previous name went out of scope.

Jeff/Roger

Jeff


Here’s what we would like to do

names

Open up thenames box

<xsl:for-each select="/FitnessCenter/Member"> Add this iteration’s Name and a slash to the open names box </xsl:for-each>

Iterate througheach name, adding intothe open box

Jeff/David/RogerClose the box

names

Jeff … / … David … / … Roger


Output to a variableIn all previous examples of creating a variable we declared the name of the variable and then had a select attribute which gave the variable its value. We can omit the select attribute:

<xsl:variable name=“names”> Do stuff in here. All output will go into the names “box”.</xsl:variable>


Example for output to a variable

Member's Names:<xsl:variable name="names"> <xsl:value-of select="/FitnessCenter/Member[1]/Name"/> <xsl:for-each select="/FitnessCenter/Member[position() > 1]"> <xsl:text>/</xsl:text> <xsl:value-of select="Name"/> </xsl:for-each></xsl:variable><xsl:value-of select="$names"/>


Output:

Member's Names: Jeff/David/Roger


xsl:choosexsl:choose allows you to elegantly express multiple

conditional tests. Here’s the structure:

<xsl:choose> <xsl:when test='something> [action] </xsl:when> <xsl:when test='something'> [action] </xsl:when> <xsl:otherwise> [action] </xsl:otherwise></xsl:choose>

The first xsl:when statement that evaluates to true is executed. If none evaluates to true then the xsl:otherwise statement is executed.


contains() function

• contains(string_to_be_tested, test_string) returns true if string_to_be_tested contains test_string

<xsl:if test=“contains($greeting, ‘welcome’)”> $greeting contains ‘welcome’</xsl:if>

Do Lab2,Part 2


substring-after() works too

substring-before(string, pattern)

returns the part of the string string before the occurrence of the pattern pattern. Example:

“Get the contents of Phone and put it into the variable called ‘phone’. Then extract from the content of ‘phone’ the stringbefore the '-' (i.e., the telephone exchange)”.

<xsl:variable name="phone" select="Phone"/><xsl:value-of select="substring-before($phone, '-')"/>

substring-before()


starts-with() string functionHere’s the form of this string function:

starts-with(string, pattern)

It tests if the string string starts with the pattern pattern. It returns a Boolean (i.e. true or false). Example:

<xsl:if test="starts-with(Phone, '555')"> action</xsl:if>

“If the Phone starts with the string, ‘555’ then do action”.


substring() function

substring(string, i, [len]) returns the substring of string that starts at the ith position and has length, len. The length argument len is optional. If not present then this function returns the substring starting at the ith position all the way to the end of the string. Note: the first character is at position 1 (not 0 as with some languages).

Example:

substring(‘1234567890’, 2, 5) returns ‘23456’


string-length() function

string-length(string) returns the length of the string string

Example:

string-length(‘1234567890’) returns 10


translate() functiontranslate(string, from-pattern, to-pattern)

Example. translate(“Hello”, “ABCDEFGHIJKLMNOPQRSTUVWXYZ”,“abcdefghijklmnopqrstuvwxyz”);

this will convert Hello to hello (i.e., convert to lower case)

A better approach to the above problem is:

<xsl:variable name="upperCaseChars" select=" 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' "/><xsl:variable name="lowerCaseChars" select=" 'abcdefghijklmnopqrstuvwxyz' "/>translate(“Hello”, $upperCaseChars, $lowerCaseChars)

Note: need to put the string within (single) quotes, otherwisethe XSL Processor will try to interpret it as an XML element.

Do Lab2,Part 3


Boolean and Relational Operators

• Boolean operators: not, and, or

• Relational operators: <, >, =, <=, >=, !=

• The less than and greater than signs are reserved symbols, so they need to be escaped when you use them.

< > = <= >= !=< > = <= >= !=

Want this:Use this:


Arithmetic

• The arithmetic operators available: +, -, *, div, mod (remainder from doing a division)– Note: recall that an XML element can have a

dash in the name. So, if you want to indicate subtraction, be sure to surround “-” with blank spaces.


Arithmetic functions

• sum(node set) this function sums up all the values in the set of nodes

• floor(number) returns the largest integer that is not greater than number

– Example. floor(2.5) returns 2

• ceiling(number) returns the smallest integer that is not less than number

– Example. Ceiling(2.5) returns 3

• round(number) returns the integer closest to number

– Example. round(2.3) returns 2


Enhanced XML Document<?xml version="1.0"?><FitnessCenter> <Member id="1" level="platinum"> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> <MembershipFee>340</MembershipFee> </Member> <Member id="2" level="gold"> <Name>David</Name> <Phone type="home">383-1234</Phone> <Phone type="work">383-4321</Phone> <FavoriteColor>lightblue</FavoriteColor> <MembershipFee>500</MembershipFee> </Member> <Member id="3" level="platinum"> <Name>Roger</Name> <Phone type="home">888-1234</Phone> <Phone type="work">888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> <MembershipFee>340</MembershipFee> </Member></FitnessCenter>

Note that each Membernow has MembershipFeeelement


Compute Membership Revenue

Membership Fee Revenue: <xsl:value-of select="sum(//MembershipFee)"/>



Coloring alternate rows

Member Names:<TABLE border="1" width="25%"> <xsl:for-each select="/FitnessCenter/Member"> <TR> <xsl:if test="position() mod 2 = 0"> <xsl:attribute name="bgcolor">yellow</xsl:attribute> </xsl:if> <TD><xsl:value-of select="Name"/></TD> </TR> </xsl:for-each></TABLE>


For each even row of the table, the TR value will be: <TR bgcolor="yellow">


count() function

count(set of node) returns an integer representing the numberof nodes (i.e., XML elements) in the set.

Example.

Number of members = <xsl:value-of select="count(//Member)"/>

Output:Number of members = 5 Do Lab2,

Part 4


Selecting all Elements/Attributes

<xsl:for-each select="/FitnessCenter/Member"> <xsl:for-each select="@*"> ... </xsl:for-each> <xsl:for-each select="*"> ... </xsl:for-each> </xsl:for-each>

For each attribute do ...

For each child elementdo ...


Namecalling with the name() Function

<xsl:for-each select="/FitnessCenter/Member"> <xsl:for-each select="@*"> Attribute = <xsl:value-of select="name(.)"/> </xsl:for-each> <xsl:for-each select="*"> Element = <xsl:value-of select="name(.)"/> </xsl:for-each> </xsl:for-each>


name(node) returns the name of node


Use Curly Braces if

• the attribute is a literal result element (where you literally type what should be output)

Example: <a href=“#{@id}”>• the name attribute of xsl:attribute

Example: <xsl:attribute name =“{@value}”>• the name attribute of xsl:pi

Example: <xsl:pi name =“{@value}”>• the name attribute of xsl:element

Example: <xsl:element name =“{@value}”>• the optional attributes of xsl:sort:

Example: <xsl:sort order =“{@value}”>


document( ) Function

• This function enables you to access other XML documents (besides the XML document that you specify when you invoke the XSL Processor).

• The format for using the document() function is: document(url), where url is a URL to another XML document


Fitness Center Merger

• Another fitness center has just merged with us. They have an xml document (FitnessCenter2.xml) containing their Members.

• You are to create an XSL-enhanced HTML document that creates a single table comprised of all the Members from both fitness clubs.


<TABLE border="1" width="75%"> <TR><TH>Name</TH><TH>Phone(home)</TH>...</TR> <xsl:for-each select="/FitnessCenter/Member"> <TR> <TD><xsl:value-of select="Name"/></TD> <TD><xsl:value-of select="Phone[@type='home']"/></TD> <TD><xsl:value-of select="Phone[@type='work']"/></TD> <TD><xsl:value-of select="FavoriteColor"/></TD> </TR> </xsl:for-each> <xsl:variable name="fitnessCenter2" select="document('file://localhost/xml-course/.../FitnessCenter2.xml')"/> <xsl:for-each select="$fitnessCenter2/FitnessCenter/Member"> <TR> <TD><xsl:value-of select="Name"/></TD> <TD><xsl:value-of select="Phone[@type='home']"/></TD> <TD><xsl:value-of select="Phone[@type='work']"/></TD> <TD><xsl:value-of select="FavoriteColor"/></TD> </TR> </xsl:for-each></TABLE>


Do Lab3,Part 1

<xsl:template match="/"> <HTML> <HEAD> <TITLE>Fitness Center</TITLE> </HEAD> <BODY> <xsl:call-template name="displayNameWithFont"> <xsl:with-param name="fontFace" select="'Impact'"/> <xsl:with-param name="name" select="/FitnessCenter/Member[1]/Name"/> </xsl:call-template> <BR/> ... </BODY> </HTML> </xsl:template>

<xsl:template name="displayNameWithFont"> <xsl:param name="fontFace" select="'Braggadocio'"/>  <xsl:param name="name"/> <FONT face="{$fontFace}"> <xsl:value-of select="$name"/> </FONT> </xsl:template>


<xsl:template match="/"> <HTML> <HEAD> <TITLE>Fitness Center</TITLE> </HEAD> <BODY> 16 / 2 = <xsl:variable name="result"> <xsl:call-template name="NumDiv2"> <xsl:with-param name="N" select="16"/> </xsl:call-template> </xsl:variable> <xsl:value-of select="$result"/> </BODY> </HTML> </xsl:template>

<xsl:template name="NumDiv2"> <xsl:param name="N"/> <xsl:value-of select="$N div 2"/> </xsl:template>

(see html-example22)Do Lab3,

Part 2


generate-id()

• Use this function to generate a unique string for a node

Example.

generate-id(/FitnessCenter/Member[1])

will return a unique id for the first Member


Using generate-id() to Uniquely Identify Elements

• In html-example08 we created two tables - a table containing the Members Names, and a separate table containing home Phone numbers. Each Name was hyperlinked to his/her home Phone. We used the id attribute on each Member element to link the two tables together.

• Suppose there is no id attribute. We can use generate-id() to create a unique identifier.


<TABLE border="1" width="25%"> <TR><TH>Name</TH></TR> <xsl:for-each select="/FitnessCenter/Member"> <TR><TD> <A href="#{generate-id(.)}"> <xsl:value-of select="Name"/> </A> </TD></TR> </xsl:for-each> </TABLE> <BR/><BR/><BR/><BR/><BR/> <TABLE border="1" width="25%"> <TR><TH>Home Phone Number</TH></TR> <xsl:for-each select="/FitnessCenter/Member"> <TR><TD> <A name="{generate-id(.)}"> <xsl:value-of select="Phone[@type='home']"/> </A> </TD></TR> </xsl:for-each> </TABLE> (see html-example23)


Using XSLT and XPath to Transform XML Documents

Part II


Transformation Language

• XSL may be used as a transformation language --> it may be used to transform an XML document into another XML document (perhaps the new one is the same, minus company sensitive data)

Transformation Engine(XSL Processor)

XSL

XML XML


Example: Filter Gold Members<?xml version="1.0"?><FitnessCenter> <Member id="1" level="platinum"> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> <Member id="2" level="gold"> <Name>David</Name> <Phone type="home">383-1234</Phone> <Phone type="work">383-4321</Phone> <FavoriteColor>lightblue</FavoriteColor> </Member> <Member id="3" level="platinum"> <Name>Roger</Name> <Phone type="home">888-1234</Phone> <Phone type="work">888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> </Member></FitnessCenter>

<?xml version="1.0"?><FitnessCenter> <Member id="1" level="platinum"> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> <Member id="3" level="platinum"> <Name>Roger</Name> <Phone type="home">888-1234</Phone> <Phone type="work">888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> </Member></FitnessCenter>


XML Transformations - all about (Template) “Rules”

• “Hey xsl processor, when you encounter the root element (e.g., FitnessCenter) do [action1]”

• “Hey xsl processor, when you encounter the Member element do [action2]”

• And so forth


XML Transformations - all about (Template) “Rules”

• Each template rule has two parts:– A pattern or matching part, that identifies the

XML node in the source document to which the action part is to be applied. Matching information is contained in an attribute.

– An action part that details the transformation of the node


XSL Document Structure<?xml version=“1.0”?><xsl:stylesheet> <xsl:template match=“/”> [action] </xsl:template> <xsl:template match=“FitnessCenter”> [action] </xsl:template> <xsl:template match=“Member”> [action] </xsl:template> ...</xsl:stylesheet>


Template Rules

Template rules take the following general form:

<xsl:template match=“pattern”> [action]

</xsl:template>


Template Rules (Example)

<xsl:template match=“Member”> <xsl:apply-templates/></xsl:template>

“Hey XSL processor, as you parse through the XML documentand you get to a <Member> element use this template rule.”

<xsl:template match=“Member”>

“Go to each of my children (the Member children) and apply the template rules to them.”

<xsl:apply-templates/>


TerminologyIn FitnessCenter.xml we have (snippet):

<FitnessCenter> <Member> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> ...</FitnessCenter>

“Member is a child element of the FitnessCenter element. Name, Phone,Phone, and FavoriteColor are children elements of the Member element.Member is a parent of Name. FitnessCenter and Member are ancestors of Name.”


xsl:element

• Suppose that you are writing a stylesheet to generate an XML document. Obviously, you will need your stylesheet to output elements.– xsl:element is used to create elements

<xsl:element name=“element-name”> [contents of the new element]</xsl:element>

<element-name> [contents of the new element] </element-name>

creates


Identity Transformation

• For our first example, lets create a stylesheet which simply creates an XML document that is a copy of the input XML document


Document/



ElementMember

ElementMember

ElementMember

ElementName

ElementPhone

ElementPhone


... ...

TextJeff

Text555-1234

Text555-4321

Textlightgrey

...


<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml"/>

<xsl:template match="/"> <xsl:apply-templates/> </xsl:template>

<xsl:template match="FitnessCenter"> <xsl:element name="FitnessCenter"> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="Member"> <xsl:element name="Member"> <xsl:apply-templates/> </xsl:element> </xsl:template>

Cont. -->


<xsl:template match="Name"> <xsl:element name="Name"> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="Phone"> <xsl:element name="Phone"> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="FavoriteColor"> <xsl:element name="FavoriteColor"> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="text()"><xsl:value-of select="."/>

</xsl:template>

</xsl:stylesheet>

(see xml-example01)


<?xml version="1.0" encoding="UTF-8"?><FitnessCenter> <Member> <Name>Jeff</Name> <Phone>555-1234</Phone> <Phone>555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> <Member> <Name>David</Name> <Phone>383-1234</Phone> <Phone>383-4321</Phone> <FavoriteColor>lightblue</FavoriteColor> </Member> <Member> <Name>Roger</Name> <Phone>888-1234</Phone> <Phone>888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> </Member></FitnessCenter>

Note that we've lost the attribute on the Member element


<xsl:template match="Member"> <xsl:element name="Member"> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each> <xsl:apply-templates/> </xsl:element> </xsl:template>

For each attribute Add an attribute to the element being output. The name of the attribute is the name of the current attribute being processed. The value of the attribute is the value of the current attribute being processed.

Getting Member’s Attribute:

(see xml-example02)


<?xml version="1.0" encoding="UTF-8"?><FitnessCenter> <Member level=“platinum”> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> <Member level=“gold”> <Name>David</Name> <Phone type="home">383-1234</Phone> <Phone type="work">383-4321</Phone> <FavoriteColor>lightblue</FavoriteColor> </Member> <Member level=“platinum”> <Name>Roger</Name> <Phone type="home">888-1234</Phone> <Phone type="work">888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> </Member></FitnessCenter>


Generalize

• Our identity stylesheet will only work for FitnessCenter XML documents. We can make a stylesheet which does an identity transformation on any XML document.

112Copyright (c) [2001]. Roger L. Costello. All Rights Reserved. <?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml"/>


<xsl:template match="*"> <xsl:element name="{name(.)}"> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="text()"><xsl:value-of select="."/>

</xsl:template>

</xsl:stylesheet> (see xml-example03)


Default Template Rules

• Every xsl document has two default template rules

• These rules are applied when the XSL Processor cannot find a template rule to use in your stylesheet

• Here are the two default template rules:

<xsl:template match=“/ | *”><xsl:apply-templates/>

</xsl:template>

<xsl:template match=“text()”><xsl:value-of select=“.”/>

</xsl:template>

“Match on the document orany element. The action is to goto the children and execute theirtemplate rules.”

“Match on a text node. The actionis to output the value of the textnode.”


Multiple Applicable Rules

Suppose that the XSL Processor is processing FitnessCenterand it gets to the <Member> element. Why does it use: <xsl:template match=“Member”>...and not the default template rule: <xsl:template match=“/ | *”>...??? After all, both apply.

Answer: given two rules that apply, the more specific rule wins.--> Clearly, “*” is much more general than “Member”. “*” matches on any element. “Member” just matches

on the Member element.


<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml"/> <xsl:template match="*"> <xsl:element name="{name(.)}"> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each> <xsl:apply-templates/> </xsl:element> </xsl:template></xsl:stylesheet>

(see xml-example04)

Now that we know about the default template rules, we can further reduce the size of the stylesheet.


<xsl:apply-templates select=“pattern”>

• The xsl:apply-templates element (without the select attribute) tells the XSL Processor to apply the template rules to all children (in document order)

• The xsl: apply-templates element can have a select attribute that tells the XSL Processor to process only the child element that matches “pattern”. – Thus, the select attribute rule enables us to specify the order in

which the children are processed


<xsl:apply-templates select=“pattern”>

<xsl:template match="Member"> <xsl:apply-templates select="Name"/> <xsl:apply-templates select="Phone[@type='work']"/></xsl:template>"Go to the template rule for my Name child element. Thengo to the template rule for the work Phone child element."

<xsl:template match="Member"> <xsl:apply-templates select="*"/></xsl:template>"Go to all the child element nodes (not to any child text nodes)."

Do Lab4,Part 1-4


mode Attribute

• Allows you to create multiple template rules for the same element. Each template rule can process the element differently.

• So, you can have multiple template rules for the same element. Just give each template rule a different mode

<xsl:template match="Name" mode="Normal">

<xsl:template match="Name" mode="footnote">


Problem

• Identity transform the FitnessCenter.xml document. However, after you have copied all the Members, follow up with a (new) GoldMembers section, containing the name of each gold member (within stars)

• The next slide shows what the output XML file should look like

120Copyright (c) [2001]. Roger L. Costello. All Rights Reserved. <?xml version="1.0" encoding="UTF-8"?><FitnessCenter> <Member level="platinum"> <Name>Jeff</Name> <Phone>555-1234</Phone> <Phone>555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member> <Member level="gold"> <Name>David</Name> <Phone>383-1234</Phone> <Phone>383-4321</Phone> <FavoriteColor>lightblue</FavoriteColor> </Member> <Member level="platinum"> <Name>Roger</Name> <Phone>888-1234</Phone> <Phone>888-4321</Phone> <FavoriteColor>lightyellow</FavoriteColor> </Member> <GoldMembers> <Name>***David***</Name> </GoldMembers></FitnessCenter>

(see xml-example05)

Note that thenames hereare processeddifferentlythan the namein the GoldMemberssection

121Copyright (c) [2001]. Roger L. Costello. All Rights Reserved. <?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml"/>


<xsl:template match="FitnessCenter"> <xsl:element name="FitnessCenter"> <xsl:apply-templates/> <xsl:element name="GoldMembers"> <xsl:for-each select="Member[@level='gold']"> <xsl:apply-templates select="Name" mode="footnote"/> </xsl:for-each> </xsl:element> </xsl:element> </xsl:template>

<xsl:template match="Member"> <xsl:element name="Member"> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each> <xsl:apply-templates mode="Normal"/> </xsl:element> </xsl:template>


<xsl:template match="Name" mode="Normal"> <xsl:element name="Name"> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="Name" mode="footnote"> <xsl:element name="Name"> <xsl:text>***</xsl:text> <xsl:apply-templates/> <xsl:text>***</xsl:text> </xsl:element> </xsl:template>

<xsl:template match="Phone" mode="Normal"> <xsl:element name="Phone"> <xsl:apply-templates/> </xsl:element> </xsl:template>

<xsl:template match="FavoriteColor" mode="Normal"> <xsl:element name="FavoriteColor"> <xsl:apply-templates/> </xsl:element> </xsl:template>

</xsl:stylesheet>

Do Lab5,Part 1


Stylesheet Reuse via xsl:include and xsl:import

• The elements xsl:include and xsl:import enable you to reuse other stylesheets.

• These elements are “top-level elements”. This means that they must be immediate children of the xsl:stylesheet element (i.e., they cannot be within a template rule)

• The xsl:include element is basically a macro substitution - the element is replaced by the contents of stylesheet it references


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

<xsl:variable name="lcase" select="'abcdefghijklmnopqrstuvwxyz'"/><xsl:variable name="ucase" select="'ABCDEFGHIJKLMNOPQRSTUVWXYZ'"/>

<xsl:template match="*"> <xsl:apply-templates select="@* | * | text() | comment() | processing-instruction()"/></xsl:template>

<xsl:template match="@*"> <xsl:value-of select="translate(.,$lcase, $ucase)"/></xsl:template>

<xsl:template match="text()"> <xsl:value-of select="translate(.,$lcase, $ucase)"/></xsl:template>

</xsl:stylesheet>

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

<xsl:include href="file://localhost/xml-course/new-xsl/toUpperCase.xsl"/>

<xsl:template match="FitnessCenter"> ... </xsl:template> ...</xsl:stylesheet>

Replace the xsl:includeelement with the contentsof the referenced stylesheet(i.e., all the children ofxsl:stylesheet)

toUpperCase.xsl


xsl:import

• xsl:import acts just like xsl:include - the stylesheet that it references is macro-substituted. However, there is a difference:

– With xsl:include the stuff that is macro-substituted into the stylesheet has the same precedence as the rest of the stylesheet. It is as though you had one stylesheet.

– With xsl:import the stuff that is macro-substituted into the stylesheet has lower precedence than the rest of the stylesheet. Also, all xsl:import elements must come first in the stylesheet.


Using Long Names for Xpath Expressions

Part III


Problem: iterate through ancestors

• Suppose that in your stylesheet you are at an arbitrary node in the XML tree. How would you output the name of all of its ancestor nodes?

Will this work: <xsl:value-of select="name(..)"/> <xsl:value-of select="name(../..)"/> <xsl:value-of select="name(../../..)"/>How many of these should we do? We don't know since we are at an arbitrary node!


Problem: get the previous sibling and following sibling

• Suppose that in your stylesheet you are at an arbitrary node in the XML tree. How would you output the name of its previous sibling and following sibling?


Long Notation

• Thus far we have used the abbreviated notation for expressing a path to a node. As we see there are some things for which the abbreviated notation is inadequate

• The long notation gives you the ability to express things that can't be expressed using the short notation

130Copyright (c) [2001]. Roger L. Costello. All Rights Reserved. Document

/



ElementMember

ElementName

ElementPhone

ElementPhone


TextJeff

Text555-1234

Text555-4321

Textlightgrey

ancestors

precedingsibling

followingsiblings

If we are currently at the Member's first phone element then: we can select all ancestors by: all preceding siblings by: all following siblings by: ancestor::* preceding-sibling::* following-sibling::* Which yields: Which yields: Which yields: Member Name Phone FitnessCenter FavoriteColor

131Copyright (c) [2001]. Roger L. Costello. All Rights Reserved. Document

/



ElementMember

ElementName

ElementPhone

ElementPhone


TextJeff

Text555-1234

Text555-4321

Textlightgrey

(the other Member elements)

descendants

If we are currently at the FitnessCenter element then: we can select all descendants by: descendant::* Which yields: Member Name Phone, etc

(see axis-example01)


Axis

• ancestor, preceding-sibling, following-sibling, and descendent each provide a different way of navigating the XML tree.

• They are each called an axis

• On the next slide, we have a list of axis


• ancestor: selects all ancestors

• ancestor-or-self: selects the current node plus all its ancestors

• attribute: selects all the attributes

• child: selects all the children

• descendant: selects all the descendants

• descendant-or-self: selects the current node plus all its descendants

• following: selects everything in the document that follows the current node

• following-sibling: selects the siblings that follow

• namespace: selects all the namespaces that are in scope

• parent: selects the parent

• preceding: selects everything in the document that precedes the current node

• preceding-sibling: selects the siblings that precede

• self: selects the current node (see axis-example02)


<xsl:template match="Member"> Member is the starting node <br/> <br /> Its ancestors are: <br/> <xsl:for-each select="ancestor::*"> <xsl:value-of select="name(.)" /> <br/> </xsl:for-each><br /> Its preceding siblings are: <br/> <xsl:for-each select="preceding-sibling::*"> <xsl:value-of select="name(.)" /> <br/> </xsl:for-each> <br/> Its following siblings are: <br/> <xsl:for-each select="following-sibling::*"> <xsl:value-of select="name(.)" /> <br/> </xsl:for-each> <br/> </xsl:template>

Example


Using XSLT and XPath to Transform XML Documents that

contain Namespaces

Part IV


ProblemSuppose that the document that we are processing is using namespaces:

<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="FitnessCenter.xsl"?><FitnessCenter xmlns="http://www.gym.com"> <Member level="platinum"> <Name>Jeff</Name> <Phone type="home">555-1234</Phone> <Phone type="work">555-4321</Phone> <FavoriteColor>lightgrey</FavoriteColor> </Member></FitnessCenter>

Note that we have a default namespace declaration. Thus, FitnessCenter, Member, Name, Phone, and FavoriteColor all belong to the http://www.gym.com namespace.

137Copyright (c) [2001]. Roger L. Costello. All Rights Reserved. <?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="html"/>

<xsl:template match="/"> <HTML><BODY> <xsl:apply-templates/> </BODY></HTML> </xsl:template>

<xsl:template match="*"> <xsl:apply-templates/> </xsl:template>

<xsl:template match="Member"> Your name is: <xsl:value-of select="Name/text()"/> </xsl:template>

<xsl:template match="text()"> </xsl:template>

</xsl:stylesheet> (see namespaces-example01)

Output:-- empty --


Why is the output empty?

<xsl:template match="Member"> Your name is: <xsl:value-of select="Name/text()"/></xsl:template>

This template does not match any element in the instance document!This template matches on a Member element in no namespace.However, in our instance document the Member element is in thehttp://www.gym.org namespace, i.e.,

{http://www.gym.com}Member


Namespace Terminology

{http://www.gym.com}Member

Expanded name = The combination of the namespace URI and the local name

Local name

Namespace URI


Namespace Terminology (cont.)

<gym:FitnessCenter xmlns:gym="http://www.gym.com"> <gym:Member> …</gym:FitnessCenter>

<gym:Member>

prefix


local-name()

• This is a built-in function which returns a string, corresponding to the local name of the element.

<xsl:template match="*"> Local name = <xsl:value-of select="local-name(.)"/> <xsl:apply-templates/></xsl:template>

Output:Local name = FitnessCenterLocal name = MemberLocal name = NameLocal name = PhoneLocal name = PhoneLocal name = FavoriteColor

(see namespaces-example02)


<?xml version="1.0"?><xsl:stylesheet xmlns:xsl=http://www.w3.org/1999/XSL/Transform version="1.0"> <xsl:output method="html"/> <xsl:template match="/"> <HTML> <BODY> <xsl:apply-templates/> </BODY></HTML> </xsl:template> <xsl:template match="*"> <xsl:apply-templates/> </xsl:template>

<xsl:template match="*[local-name()='Member']"> Your name is: <xsl:value-of select="*[local-name(.)='Name']/text()"/> </xsl:template>

<xsl:template match="text()"> </xsl:template>

</xsl:stylesheet>

Output:Your name is: Jeff


Alternatively<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:gym="http://www.gym.com" version="1.0"> <xsl:output method="html"/> <xsl:template match="/"><HTML><BODY><xsl:apply-templates/> </BODY></HTML> </xsl:template> <xsl:template match="*"><xsl:apply-templates/></xsl:template>

<xsl:template match="gym:Member"> Your name is: <xsl:value-of select="gym:Name"/> </xsl:template>

<xsl:template match="text()">  </xsl:template>

</xsl:stylesheet>

Declare the gym namespace

Match on the Member elementin the gym namespace

Select the Name element inthe gym namespace


namespace-uri()• This is a built-in function which returns a string

corresponding to the namespace URI of the node.

<xsl:template match="*"> Local name = <xsl:value-of select="local-name(.)"/> Namespace URI = <xsl:value-of select="namespace-uri(.)"/> <xsl:apply-templates/></xsl:template>

Output:Local name = FitnessCenterNamespace URI = http://www.gym.comLocal name = MemberNamespace URI = http://www.gym.comLocal name = NameNamespace URI = http://www.gym.comLocal name = PhoneNamespace URI = http://www.gym.com... (see namespaces-example05)


name() Revisited

• We have seen the name() function before. It returns the name of the node. But what name does it return if the node is in a namespace?– Answer: it returns the element name and its

prefix (this is called the QName, for Qualified Name)


<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="FitnessCenter.xsl"?><gym:FitnessCenter xmlns:gym="http://www.gym.com"> <gym:Member level="platinum"> <gym:Name>Jeff</gym:Name> <gym:Phone type="home">555-1234</gym:Phone> <gym:Phone type="work">555-4321</gym:Phone> <gym:FavoriteColor>lightgrey</gym:FavoriteColor> </gym:Member></gym:FitnessCenter>

<xsl:template match="*"> Local name = <xsl:value-of select="local-name(.)"/> Namespace URI = <xsl:value-of select="namespace-uri(.)"/> Name = <xsl:value-of select="name(.)"/> <xsl:apply-templates/></xsl:template>


Output:Local name = FitnessCenterNamespace URI = http://www.gym.comName = gym:FitnessCenterLocal name = MemberNamespace URI = http://www.gym.comName = gym:MemberLocal name = NameNamespace URI = http://www.gym.comName = gym:NameLocal name = PhoneNamespace URI = http://www.gym.comName = gym:PhoneLocal name = PhoneNamespace URI = http://www.gym.comName = gym:PhoneLocal name = FavoriteColorNamespace URI = http://www.gym.comName = gym:FavoriteColor



Identity transform - copying namespace declarations

• Recall our identity transform stylesheet:<xsl:template match="*"> <xsl:element name="{name(.)}"> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each> <xsl:apply-templates/> </xsl:element></xsl:template>

Iterate through eachattribute and add themas attributes onto the element.


@* does not select namespace declarations!

• The @* will only select non-namespace declaration attributes. It will not select namespace declaration attributes

<Library xmlns="http://www.library.org" xmlns:xsi=" http://www.w3.org/2001/XMLSchema-instance" id="Boston Public Library">

This will be selected by @*

These will not be selected by @*


Identity transformation for XML documents containing namespaces?

• So how do we create a stylesheet that can copy over namespace declarations, along with the other attributes?– Answer: use the <xsl:copy/> element

• This element will copy the current element and all namespace declarations to the output file.



<xsl:template match="* | @*"> <xsl:copy> <xsl:apply-templates select="@*"/> <xsl:apply-templates/> </xsl:copy> </xsl:template>

</xsl:stylesheet>


The problem with this identity transform stylesheet is that it's not set upto allow us to make changes to elements/attributes.



<xsl:template match="*"> <xsl:element name="{name(.)}"> <xsl:copy-of select="namespace::*" /> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each>


</xsl:element> </xsl:template>

</xsl:stylesheet>

Error! Attemptingto create anelement in anamespace, butthe namespacehas not beendeclared yet!



<xsl:template match="*"> <xsl:element name="{name(.)}" namespace="{namespace-uri(.)}"> <xsl:copy-of select="namespace::*" /> <xsl:for-each select="@*"> <xsl:attribute name="{name(.)}" namespace="{namespace-uri(.)}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each>


</xsl:element> </xsl:template>

</xsl:stylesheet>

Simultaneouslydeclare theelement and its namespace

Simultaneouslydeclare theattribute and its namespace



The End

Thanks for your attention!