ITR3 lecture 3: Namespaces, XML Schema

1
ITR3 lecture 3 Namespaces, XML Schema XSL

• Thomas Krichel
• 2002-09-10

2
Gee.

• Birdseye view only, have a look at what these
  things do.
• If there is interest, I can teach some more in a
  separate course.
• Structure
• Some XML related standards
• Namespaces
• XML Schema
• XSL

3
Literature

• Castro, Elizabeth (2001). XML for the World Wide
  Web Visual QuickStart Guide. Peachpit Press.
• Duckett, Jon et al. (2001). Professional XML
  Schemas. Wrox Press (recommended)
• Kay, Michael (2001). XSLT (2nd ed.). Wrox Press.

4
XHTML

• This is HTML redefined so that it becomes
  well-formed XML
• Examples
• Case-sensitive elements
• ltpgt replaced by ltp/gt
• Verdict pain without gain

5
Resource Description Framework (RDF)

• A standard issued by the W3C. A framework to
  encode meaning to make it computer processable.
• Uses the approach of a directed graph.
• Generalizes an object / property / value approach
• Value may be another object.
• Objects are URI identified by a URI.
• Properties may be identified with a URI
• A paper on RDF available at http//openlib.org/hom
  e/krichel/papers/anhalter.letter.pdf
• RDF XML syntax is defined but currently being
  reworked.
• Verdict very costly to implement.

6
Cascading style sheets (CSS)

• a non-XML way of writing stylesheets that can be
  applied to both XML and HTML. Widely supported by
  browsers.
• Written as a sequence of rules. Example
• compositionyear, recordingyear
• color red
• font-family sans-serif
• Verdict not flexible

7
XPath and XPointer

• are non-XML syntaxes referring to parts of an XML
  document, specific
• Ranges
• points
• sets of XML document.
• There are used in other XML related standards, in
  particular, in XSL will be covered as part of
  XSL.
• Verdict useful

8
XLinks

• is an XML syntax to link XML documents.
• They go way beyond the conventional linking
  capabilities of HTML, but there is no obvious way
  for the browser to represent them.
• Verdict nonsense

9
Document Object Model DOM

• a platform- and language-neutral interface that
  will allow programs and scripts to dynamically
  access and update the content, structure and
  style of documents. The Document Object Model
  provides a standard set of objects for
  representing HTML and XML documents, a standard
  model of how these objects can be combined, and a
  standard interface for accessing and manipulating
  them.
• Now at ''Level 3''.
• Works by building a tree out of a document.
• Verdict exxxtremly complicated

10
Simple API for XML (SAX)

• SAX is an event-based paring model. It reports
  parsing events (such as the start and end of
  elements) directly to the application through
  callbacks
• Does not usually build an internal tree.
• A lot less resource-intensive,
• when the document is large
• when the task is simple.
• Verdict thumbs up!

11
XML Information Sets

• best understood through an example. Consider two
  XML snippets.
• Snippet 1
• ltperson sex"female"gt Margarete
  Krichellt/persongt
• Snippet 2
• ltperson sex'female'gtMargarete Krichel
  lt/persongt
• Are they the same?

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XML Namespaces

• Allow to make XML element names and attribute
  name globally unique by associating them with a
  particular URI, usually a URL.
• The globally unique name is called the qualified
  name or qname, for short.
• The name without the namespace URI called the
  local name.
• This is done through a namespaces declaration,
  and a prefix. The namespace declaration
  associates a short string, called a prefix with
  the namespace.
• The qualified name can then be written as
  prefixlocalname

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Namespace syntax

• ltelement xmlnsprefixURIgt lt/elementgt
• element is the element name
• prefix is the prefix
• URI is a URI, often a URL, actually.
• indicate that it is optional. If the prefix
  is missing it means that all elements that have
  no namespace prefix belong, by default to the
  declared namespace.
• Namespace declaration remains local to the
  children of element.

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Avoiding cerebral indigestion related
tonamespaces

• Expect nothing if you retrieve the namespace URI,
  when it is a URL.
• Prefixes can be any short string. Some prefixes
  are customary, like xsi for http//www.w3.org/2001
  /XMLSchema-instance
• Default attributes only apply to elements not
  attributes. Attributes belong to the namespace of
  their elements, unless it has an explicit prefix.

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XML Schemas http//www.w3.org/TR/xmlschema-0/
(Primer) http//www.w3.org/TR/xmlschema-1/
(Structures) http//www.w3.org/TR/xmlschema-2/
(Datatypes)
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What is XML Schema?

• XML Schema is vocabulary for expressing
  constraints for the validity of an XML document.
• A piece of XML is valid if it satisfies the
  constraints expressed in another XML file, the
  schema file.
• The idea is to check if the XML file is fit for a
  certain purpose.

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Example
ltlocationgt ltlatitudegt32.904237lt/latitude
gt ltlatitudegt73.620290lt/longitudegt
ltuncertainty units"meters"gt2lt/uncertaintygt lt/loca
tiongt
To be valid, this XML snippet must meet all the
following constraints 1. The location must
be comprised of a latitude, followed by a
longitude, followed by an indication of the
uncertainty of the lat/lon measurements.
2. The latitude must be a decimal with a value
between -90 to 90 3. The longitude must be a
decimal with a value between -180 to 180 4.
For both latitude and longitude the number of
digits to the right of the decimal point
must be exactly six digits. 5. The value of
uncertainty must be a non-negative integer 6.
The uncertainty units must be either meters or
feet.
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Validating your data
XML instance
ltlocationgt ltlatitudegt32.904237lt/latitude
gt ltlongitudegt73.620290lt/longitudegt
ltuncertainty units"meters"gt2lt/uncertaintygt lt
/locationgt
XML Schema validator
Data is ok!
-check that the latitude is between -90 and
90 -check that the longitude is between -180 and
180 - check that the fraction digits is 6 Etc..
software
XML Schema file
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History of Schema

• Once upon a time, there was SGML
• SGML has a schema language called a DTD.
• It is crap
• Different syntax then SGML
• Main focus on presence and absence of elements
• Very limited capabilties to check contents of
  elements (datatypes)

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XML Schemas can constrain

• the structure of instance documents
• "this element contains these elements, which
  contains these other elements, etc
• the datatype of each element/attribute
• "this element shall hold an integer with the
  range 0 to 12,000"

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Highlights of XML Schemas

• 44 built-in datatypes
• Can create your own datatypes by extending or
  restricting existing datatypes
• Written in the same syntax as instance documents
• Can express sets, i.e., can define the child
  elements to occur in any order
• Can specify element content as being unique (keys
  on content) and uniqueness within a region
• Can define multiple elements with the same name
  but different content
• Can define elements with nil content
• Can define substitutable elements

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important schema concepts

• simple types types that can not have child
  elements
• elements that only have text contents and no
  attributes
• attributes
• complex type type of anything that can have
  child attributes

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important schema concepts

• global declarations are direct children of the
  root schema element. They are visible everywhere.
• all local declarations are local and are limited
  in scope to the element that they appear within

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important schema concepts

• Value space. The range of values that the type
  can take
• Lexical space. The range litterals that represent
  the value
• Set of facets. The defining properties of a type.
  
• Fundamental facets include equality, order,
  bounds, cardinality, numeric/non-numeric
• Constraining facets include ranges for numbers,
  string lengths, or a regular expressions

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Namespaces

• XML Schema file mixes vocabulary from the XML
  Schema language with own vocabulary to be
  created.
• Has to keep both separate using namespaces.
• Namespaces associate a URI with names.

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http//www.w3.org/2001/XMLSchema
http//www.books.org (targetNamespace)
complexType
element
BookStore
Author
sequence
Book
schema
Title
boolean
string
ISBN
Publisher
Date
integer
This is the vocabulary that XML Schemas provide
to define your new vocabulary
This is the vocabulary for our book store xml
description.
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lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.books
.org" xmlns"http//www.book
s.org" elementFormDefault"q
ualified"gt ltxsdelement name"BookStore"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Book"
minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt lt/xsdcomplexTypegt
lt/xsdelementgt ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title"
minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Author" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Date" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"ISBN" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Publisher" minOccurs"1" maxOccurs"1"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
(explanations on succeeding pages)
BookStore.xsd (see example01)
xsd Xml-Schema Definition
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lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.books
.org" xmlns"http//www.book
s.org" elementFormDefault"q
ualified"gt ltxsdelement name"BookStore"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Book"
minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt lt/xsdcomplexTypegt
lt/xsdelementgt ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title"
minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Author" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Date" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"ISBN" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Publisher" minOccurs"1" maxOccurs"1"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
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lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.book
s.org" xmlns"http//www.bo
oks.org"
elementFormDefault"qualified"gt ltxsdelement
name"BookStore"gt ltxsdcomplexTypegt
ltxsdsequencegt ltxsdelement
ref"Book" minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Author" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Date" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"ISBN" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Publisher" minOccurs"1"
maxOccurs"1"/gt lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
All XML Schemas have "schema" as the root element.
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lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.book
s.org" xmlns"http//www.bo
oks.org"
elementFormDefault"qualified"gt ltxsdelement
name"BookStore"gt ltxsdcomplexTypegt
ltxsdsequencegt ltxsdelement
ref"Book" minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Author" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Date" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"ISBN" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Publisher" minOccurs"1"
maxOccurs"1"/gt lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
The elements and datatypes that are used to
construct schemas - schema - element -
complexType - sequence - string come from the
http///XMLSchema namespace
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XMLSchema Namespace
http//www.w3.org/2001/XMLSchema
complexType
element
sequence
schema
boolean
string
integer
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lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.books
.org" xmlns"http//www.book
s.org" elementFormDefault"q
ualified"gt ltxsdelement name"BookStore"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Book"
minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt lt/xsdcomplexTypegt
lt/xsdelementgt ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title"
minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Author" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Date" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"ISBN" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Publisher" minOccurs"1" maxOccurs"1"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
Says that the elements defined by this schema -
BookStore - Book - Title - Author - Date
- ISBN - Publisher are to go in
this namespace
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Book Namespace (targetNamespace)
http//www.books.org (targetNamespace)
BookStore
Author
Book
Title
ISBN
Publisher
Date
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lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.books
.org" xmlns"http//www.book
s.org" elementFormDefault"q
ualified"gt ltxsdelement name"BookStore"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Book"
minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt lt/xsdcomplexTypegt
lt/xsdelementgt ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title"
minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Author" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Date" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"ISBN" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Publisher" minOccurs"1" maxOccurs"1"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
The default namespace is http//www.books.org whic
h is the targetNamespace!
This is referencing a Book element
declaration. The Book in what namespace?
35
lt?xml version"1.0"?gt ltxsdschema
xmlnsxsd"http//www.w3.org/2001/XMLSchema"
targetNamespace"http//www.books
.org" xmlns"http//www.book
s.org" elementFormDefault"q
ualified"gt ltxsdelement name"BookStore"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Book"
minOccurs"1" maxOccurs"unbounded"/gt
lt/xsdsequencegt lt/xsdcomplexTypegt
lt/xsdelementgt ltxsdelement name"Book"gt
ltxsdcomplexTypegt ltxsdsequencegt
ltxsdelement ref"Title"
minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"Author" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Date" minOccurs"1" maxOccurs"1"/gt
ltxsdelement ref"ISBN" minOccurs"1"
maxOccurs"1"/gt ltxsdelement
ref"Publisher" minOccurs"1" maxOccurs"1"/gt
lt/xsdsequencegt
lt/xsdcomplexTypegt lt/xsdelementgt
ltxsdelement name"Title" type"xsdstring"/gt
ltxsdelement name"Author" type"xsdstring"/gt
ltxsdelement name"Date" type"xsdstring"/gt
ltxsdelement name"ISBN" type"xsdstring"/gt
ltxsdelement name"Publisher" type"xsdstring"/gt
lt/xsdschemagt
This is a directive to any instance documents
which conform to this schema Any elements that
are defined in this schema must be
namespace-qualified when used in instance
documents.
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Referencing a schema in an XML instance document
lt?xml version"1.0"?gt ltBookStore xmlns
"http//www.books.org"
xmlnsxsi"http//www.w3.org/2001/XMLSchema-instan
ce" xsischemaLocation"http/
/www.books.org
BookStore.xsd"gt
ltBookgt ltTitlegtMy Life and
Timeslt/Titlegt ltAuthorgtPaul
McCartneylt/Authorgt ltDategtJuly,
1998lt/Dategt ltISBNgt94303-12021-4389
2lt/ISBNgt ltPublishergtMcMillin
Publishinglt/Publishergt lt/Bookgt
... lt/BookStoregt
1
3
2
1. First, using a default namespace declaration,
tell the schema-validator that all of the
elements used in this instance document come from
the http//www.books.org namespace. 2. Second,
with schemaLocation tell the schema-validator
that the http//www.books.org namespace is
defined by BookStore.xsd (i.e., schemaLocation
contains a pair of values). 3. Third, tell the
schema-validator that the schemaLocation
attribute we are using is the one in the XML
Schema-instance namespace.
37
XMLSchema-instance Namespace
http//www.w3.org/2001/XMLSchema-instance
schemaLocation
type
noNamespaceSchemaLocation
nil
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Referencing a schema in an XML instance document
targetNamespace"http//www.books.org"
schemaLocation"http//www.books.org
BookStore.xsd"
BookStore.xsd
BookStore.xml
- uses elements from namespace
http//www.books.org
- defines elements in namespace
http//www.books.org
A schema defines a new vocabulary. Instance
documents use that new vocabulary.
39
Note multiple levels of checking
BookStore.xml
BookStore.xsd
XMLSchema.xsd (schema-for-schemas)
Validate that the xml document conforms to the
rules described in BookStore.xsd
Validate that BookStore.xsd is a valid schema
document, i.e., it conforms to the rules
described in the schema-for-schemas
40
Using XSLT and XPath
41
XSL transforms XML

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

XSL
XSL Processor
XML
HTML (or XML or text)
42
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
• lt?xml-stylesheet type"text/xsl
  href"stylish.xsl"?gt
• Note this does not work with other browsers!

43
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.

44
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.

45
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

46
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

47
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

48
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

49
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.

50
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.

51
property of nodes attribute

• element one to many attributes that the element
  has
• other nodes empty
• Now we look at what XSL does

52
Different formats

• ltxsloutput method"xml"gt is the default
• ltxsloutput method"htmlgt
• ltxsloutput method"text"gt 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.

53
templates set rules

• ltxsltemplate match"expression"gt
• do some stuff
• ltxsltemplategt
• 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.

54
applying templates

• ltxslapply-templates/gt
• says apply all template rules on the current
  node and on all its child nodes.

55
Default, built-in rules for the nodes

• root ltxslapply-templatesgt on all children
• element ltxslapply-templatesgt 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

56
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

57
Enhancing HTML Documents with XML Data
HTML Document (with embedded XSL elements)
XML Document
XSL element
XSL Processor
XML data
XML data
58
Enhancing HTML Documents with the Following XML
Data
lt?xml version"1.0"?gt lt?xml-stylesheet
type"text/xsl" href"FitnessCenter.xsl"?gt ltFitnes
sCentergt ltMember level"platinum"gt
ltNamegtJefflt/Namegt ltPhone
type"home"gt555-1234lt/Phonegt
ltPhone type"work"gt555-4321lt/Phonegt
ltFavoriteColorgtlightgreylt/FavoriteColorgt
lt/Membergt lt/FitnessCentergt
FitnessCenter.xml
59
Embed HTML Document in an XSL Template
lt?xml version"1.0"?gt ltxslstylesheet
xmlnsxsl"http//www.w3.org/1999/XSL/Transform"
version"1.0"gt ltxsloutput
method"html"/gt ltxsltemplate match"/"gt
ltHTMLgt ltHEADgt
ltTITLEgtWelcomelt/TITLEgt lt/HEADgt
ltBODYgt Welcome!
lt/BODYgt lt/HTMLgt lt/xsltemplategt lt/xsl
stylesheetgt
FitnessCenter.xsl (see html-example01)
60
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.

61
Extracting the Member Name
lt?xml version"1.0"?gt ltxslstylesheet
xmlnsxsl"http//www.w3.org/1999/XSL/Transform"
version"1.0"gt ltxsloutput
method"html"/gt ltxsltemplate match"/"gt
ltHTMLgt ltHEADgt
ltTITLEgtWelcomelt/TITLEgt lt/HEADgt
ltBODYgt Welcome ltxslvalue-of
select"/FitnessCenter/Member/Name"/gt!
lt/BODYgt lt/HTMLgt lt/xsltemplategt lt/xsl
stylesheetgt
(see html-example02)
62
Extracting a Value from Navigating the XML
Document

• Extracting values
• use the ltxslvalue-of select""/gt 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."
63
Document /
PI lt?xml version1.0?gt
Element FitnessCenter
Element Member
Element Phone
Element Name
Element FavoriteColor
Element Phone
Text Jeff
Text 555-4321
Text lightgrey
Text 555-1234
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• Thank you for your attention!