Xml session05

Extensible Markup Language
Objectives

In this session, you will learn to:
Transform an XML document through a Cascading Style Sheet
Transform an XML document through Extensible Style Sheet
Language

Ver. 1.0 Session 5 Slide 1 of 33

Introducing Cascading Style Sheet

A CSS is a text file containing one or more rules or
definitions for the style characteristics of a particular
element.
It controls how tags are formatted in XML and HTML
documents.
The CSS file can be included in XML documents with the
same data structure.


Creating CSS

• The syntax for coding a CSS is:
elementname specifies the
elementname { name of the element.
property1: value;
property2: value;
}


Creating CSS (Contd.)

property1 and property2
elementname { specify the property names,
property1: value; such as font-family, font-size,
and color
property2: value;
}


Creating CSS (Contd.)

value specifies the property
elementname { values for a property name.
property1: value;
property2: value;
}

For example, to display the film title in red, you can
type the following code in a CSS file:
FILM {COLOR: RED}


Applying CSS

A CSS can be applied to an XML
document using the following
syntax: Instructs the browser that the
<?xml:stylesheet XML document uses a
stylesheet.
type="text/css" href="path-
name"?>


Applying CSS (Contd.)

syntax: Specifies the type of
<?xml:stylesheet formatting that is being used.

name"?>


Applying CSS (Contd.)

syntax: Specifies the name of the
<?xml:stylesheet CSS file used to format the
XML document.
name"?>


Demo: Creating a CSS

Problem Statement:
Jim, the XML developer at CyberShoppe, has been asked to
display the product details for Cybershoppe in a browser in the
following format:
The price per unit, description, and quantity on hand for each
product should be displayed in teal, with a font size of 10 pts.
The product name should be displayed in red, with a font size of
20 pts. It should be displayed in bold.
All details should be displayed in the Arial font.


Introducing XSL

CSS does not support the reorder, sort, and display of
elements based on a condition.
For such advanced formatting, XML supports Extensible
Style Sheet Language (XSL).
XSL has two parts:
XSL Transformations (XSLT)
XML Path (XPath)
XSL:
Contains instructions on how an XML document should be
transformed into an HTML or an XHTML document.
Uses XPath expressions to extract specific data from an XML
document.
The XSLT processor transforms the XML document into an
HTML or XHTML or into another XML document.


Analyzing the Working of the XSLT Processor

The XSLT processor applies the transformation information
to the source document and builds the result tree as shown
in the following figure.

MSXML Parser

XSLT style sheet XSLT tree

XSLT Result tree
processor

XML document Source tree


Formatting Data Using XSLT

XSLT provides the following elements to select and format
data:
stylesheet
value-of
for-each
sort
text


Formatting Data Using XSLT (Contd.)

data:
Instructs the browser that the document is a style
a stylesheet sheet file.
a value-of Is the root element for all XSLT style sheets.
a for-each Is written as:
<xsl:stylesheet
a sort xmlns:xsl=
a text "http://www.w3.org/1999/XSL/Transform"
version="1.0">



data:
a stylesheet
a value-of Displays the value of the specified element or
a attribute.
for-each
Follows the syntax:
a sort <xsl:value‑of
a text select="elementname/attributename"/>



data:
a stylesheet
a value-of
a for-each Instructs the XSLT processor to process the
information for each instance of the specified pattern.
a sort
Follows the syntax:
a text <xsl:for-each select="pattern">
[action to be performed]
</xsl:for-each>



data:
a stylesheet
a value-of
a for-each
a sort Sorts data based on the values assigned to elements
a text and
attributes.
Follows the syntax:
<xsl:sort select="expression"
order="ascending | descending"
case-order="upper-first | lower-first“
data-type="text | number | qname"/>



data:
a stylesheet
a value-of
a for-each
a sort
a text Generates constant text in the output and displays
labels.
Follows the syntax:
<xsl:text> Text to be displayed as
label </xsl:text>


Formatting Data Using XSL Formatting Objects

XSL Formatting Objects (XSL-FO):
Is an XML-based language that formats XML documents into
pages, paragraphs, and lists.
Provides various objects and properties that define the
formatting of XML objects.
Provides a basic document structure that contains the
formatting objects and properties.


Formatting Data Using XSL Formatting Objects (Contd.)

The following code snippet depicts the structure of an XML
document:
Is <?xml version="1.0" encoding="ISO-8859-1"?>
<fo:root
xmlns:fo="http://www.w3.org/1999/XSL/Format">
<fo:layout-master-set>
<fo:simple-page-master master-name="A4">

</fo:simple-page-master>
</fo:layout-master-set>
<fo:page-sequence master-reference="A4">

</fo:page-sequence>
</fo:root>


The XSL-FO objects provides a logical layout to an XML
document.
The content of an XML document can be split into pages.
These pages are divided into following four areas:
a Regions: Are the topmost areas in the page.
a Block areas: Are the block level elements.
a Line areas: Contain the text within the block areas.
a Inline areas: Are part of line areas.



The XSL-FO properties specifies the type of formatting that
can be specified on the XSL-FO objects.
Consider the following code-snippet:
<fo:simple-page-master master-name="right">
<fo:region-body margin-left="5in"
margin-right="2in"/>
</fo:simple-page-master> This the namedefines a template
with
element
right.

This specifies that the left margin
of the template is set to 5 inches.

This specifies that the right margin
of the template is set to 2 inches.


Creating XSLT Template Rules

A template rule:
Describes how an XML element and its contents are converted
into a specific format for displaying in the browser.
Consists of two parts:
a A pattern that identifies an XML element in an XML document.
a An action or processing code that details the transformation and
rendering of the resulting element.
XSLT uses two main elements for creating template rules:
a template
a apply-templates


Creating XSLT Template Rules (Contd.)

A template rule:
a template Defines a template for the desired
a apply-templates output.
Follows the syntax:
<xsl:template match="pattern">
[action to be taken]
</xsl:template>


Creating XSLT Template Rules (Contd.)

A template rule:
a template
a apply-templates Instructs the XSLT processor to find an
appropriate template and perform the specified
tasks on selected elements.
Follows the syntax:
<xsl:apply‑templates
[select="pattern"]>


Demo: Creating an XSLT Style Sheet to Format Data

Problem Statement:
CyberShoppe needs to display product details, such as product
ID, name, and price per unit. The following figure depicts a
sample output.

The details about the products should be displayed in red.


Practice Questions

The various departments of a university store data in
different formats. The IT department of the university
decides to use XML as the data interchange format to
transmit the data between the departments. Which of the
following would be the best approach to accomplish the task
using XML?
a. Devise a common information model and enforce its use by all
the departments that need to exchange data.
b. Implement a conversion application that can handle the data
received from other departments.


Practice Questions (Contd.)

c. Use an XSLT style sheet to convert the incoming or outgoing
XML document into the format used within the departments.
d. Modify the XML schema to use the same content model in all
departments.

Answer:
c. Use an XSLT style sheet to convert the incoming or outgoing
XML document into the format used within the departments.


Practice Questions

• Which of the following code snippets can be used in an
XML document named Test.xml to associate it with a
style sheet named Test.css?
a. <?xml-stylesheet href="Test.css"
type="text/css"?>
b. <?xml-stylesheet href="Test.xsl"
type="text/css"?>
c. <?xmlstylesheet href="Test.css"
type="text/xsl"?>
d. <xml-stylesheet href="Test.css"
type="text/css"/>

Answer:
a. <?xml-stylesheet href=”Test.css”
type=”text/css”?>


Practice Questions

Consider the following statements:
Statement A: CSS can be used to reorder, add, delete, or
perform other operations on elements.
Statement B: CSS uses less memory when compared to
XSLT.
Which of the following is correct about the preceding
statements?
a. Statement A is True, and Statement B is False.
b. Statement A is False, and Statement B is True.
c. Both, Statement A and Statement B, are True.
d. Both, Statement A and Statement B, are False.

Answer:


Practice Questions

Which element must contain one or more when elements?
a. xsl:if
b. xsl:for-each
c. xsl:sort
d. xsl:choose

Answer:
d. xsl:choose


Practice Questions

Consider the following statements:
Statement A: XSLT is a superset of the CSS functionality.
Statement B: XSLT is an application of XML.
Which of the following is correct about the preceding
statements?
a. Statement A is True, and Statement B is False.
d. Both, Statement A and Statement B, are False.

Answer:


Summary

In this session, you learned that:
Rendering is the process of formatting and presenting the data
in an XML document in different formats.
A style sheet is a document that contains the formatting rules
for one or several XML documents. The two types of style
sheets that can be used with XML documents are:
 CSS
 XSL
 CSS is used to define the style or appearance of an XML
document.
 XSL is made up of XSLT and XPath.
 XSLT is used to display selective elements or attributes, sort
data on one or more elements, and process the data based on
conditions.


Summary (Contd.)

 The XSLT processor applies the transformation information
contained in the XSLT style sheet and builds a resultant tree
structure, which is then rendered to various targets.
 XSLT elements, such as template, apply-templates,
sort, for-each, and value-of are used to extract and
format data.
 XSL-FO provides formatting objects to break XML documents
into pages, paragraphs, and lists. The associated properties of
the formatting objects allow you to format the XML documents.
 A template rule describes how an XML element and its
contents are converted into a format that can be displayed in
the browser.


Xml session05

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