3 displaying and navigating through xml

8/14/2019 3 Displaying and Navigating through XML

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XSL

Style sheets


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CSS

Cascading Style Sheet Style sheets are used to specify how

the tags will be rendered in the targetapplication.

CSS were initially designed to be used

with html. It is now used with XML too. 2 levels CSS Level 1 and Level 2


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Contemplation

If today was a perfect there would be no need for tomorrow. God


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topic {display: block;font-size: large;

}by {

display:block;

font-size:small;text-align: right;color: navy;

}body{

font: 20 pt Arial;color: red;

margin-left: 2.0 in }


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Limitation of CSS

Syntax is not XML. CSS does not filter and rearrange data.

That is you cannot reorder things, andyou cannot conditionally perform stylingwithout resorting to scripting.


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XSL

Extensible Stylesheet Language for TransformationsXSL is used to render XML document. Itovercomes the disadvantages of CSS.

Parts of XSL: XSLT (XSL transformation): vocabulary

describing the formatting of XML XSL-FO : the part that covers formatting

objects, also known as flow objects. XPath (XML Path Language): language

used to address XML document fragments


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XSLT

The XSLT transformation standard isessentially a translation mechanism that letsyou specify what to convert an XML tag into sothat it can be displayedfor example, in

HTML. Different XSL formats can then be usedto display the same data in different ways, for different uses.

XSLT works with XSLT processor. The

processor can be invoked using command linewhere xml file, xsl file and html file (where theoutput will be written) needs to be supplied .


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XPATH XML Path Language The XPATH standard is an addressing

mechanism that you use whenconstructing transformation instructions, inorder to specify the parts of the XMLstructure you want to transform.

Important in exchange of informationbetween computers because it allowsfiltering and selecting information from thesource XML document.

Used with XSLT, XPointer, XLink and otherXML-related technologies.


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Working XPath has a starting point, the context node, and then

we move on in a particular direction, called an axis. Finally we arrive at our destination moving one or more

steps called location steps.

A location step has three parts An axis A node test, which specifies the node type and

expanded name of the nodes selected by the

location step Zero or more predicates, which use arbitrary XPath

expression to further refine the set of nodes selectedby the location step.


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Example: XSTL with XPath Divinity National

Nilakandan Narayanan

Mohan Madan

XML Document withXSL linked


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Employee Data,

First NameLast

NameDate of birth

stxsl.xsl XSL document


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A template is a structured container that manages

the way a source tree or a portion of the source treeis transformed. xsl:template defines a set of rules for transforming

nodes in source document into the result tree. Thisis handled by the match attribute.

Example: Matches the

root node


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Fragrance

Rose

Fragrance Rose

XSL

XML

Result

Children of thenamed templateare processed


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Evaluates the node and returns thestring between the node.

Example:


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Selection Patterns

element name:

child elements

Selects the company node assuming that the contextnode is employee-info

descendents

Selects fname node if it is descendent of the contextnode

attributes :

Axes

Node Test Expression

Predicate / XPath Expression


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More Predicates child::employee[position()=2]

Node representing the 2nd employee element. child::employee[position()=last()]

Node representing the last employee element.

child::employee[position()=last()-1]Node representing the last but one employee element.

select="/employee-info/employee[@join=1999]"Nodes representing employee whose join attribute is1999.()


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This tag makes it possible to repeat the sameset of processing for each instance of

element specified in the pattern.


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First NameLast NameDate

of birth

XSLT with style


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To transform XML into HTML


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Conditions ..

Single condition

Multiple Condition


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Creating elements

Is used to create an element in XSL

document. Example:

Creates an tag element


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XLink and XPointer

Linking in XML is divided into two parts: XLinkand XPointer.

XLink defines a standard way of creatinghyperlinks in XML documents.

XPointer allows the hyperlinks to point tomore specific parts (fragments) in the XMLdocument.


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XPointer Syntax

If the hyperlink points to an XML document, we canadd an XPointer part after the URL in the

xlink:href attribute, to navigate (with an XPathexpression) to a specific place in the document.

3 displaying and navigating through xml

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