Presenting XML

1
Presenting XML

• Need some way to display XML
• Default is to show the tags
• Example see
• http//people.cs.uchicago.edu/dangulo/cspp53025/e
  xamples/lec2/BridgeOfDeathEpisode-NoStylesheet.xml
  
• Bring up in IE6 / NetScape7
• Want a better display
• Convert information to presentation.
• Can use cascading style sheets to control the
  appearance of tags
• including making either the tags or the text
  inside them invisible

2
XSL

• eXtensible Stylesheet Language
• Has two parts
• XSLT
• Defines transformations from XML to HTML.
• From XML to XML
• From XML to anything!
• XSL Formatting Objects
• Provides an alternative to CSS
• Formats and styles an XML document
• w3c standard (actually recommendation) see the
  w3c links off of the webpage for the definition.

3
Using XSLT

XML Servers
Client Side
IE5 Mozilla .9
Web Server
CGI
XSLT-enabled Browser
http request
XML Stylesheet
The Internet
XML response
Server Side
XSLT-engine
HTML
http request
Web Server
Servlet
The Internet
HTML
XML response
4
Dont underestimate XSLT

• XSLT is an extremely powerful language.
• For publishing applications, often the entire
  application can be performed in XSLT.
• Add prefix or suffix text to content
• Remove, create, re-order and sort elements
• Re-use elements elsewhere in the document
• Transform data between different XML dialects
• XSLT can be used like a stylesheet or embedded in
  a programming language

5
Executing the stylsheet foo.xslOn file
BridgeOfDeathEpisode.xml

• foo.xsl lt?xml version"1.0"?gt ltxslstylesheet
  xmlnsxsl "http//www.w3.org/1999/XSL/Transform
  " version"1.0"gt ltxsltemplate
  match/gt ltHTMLgtlttitlegtHWlt/titlegtltBODYgtHELLO
  WORLD lt/BODYgtlt/HTMLgt lt/xsltemplategt lt/xsls
  tylesheetgt
• BridgeOfDeath.html lthtmlgtlttitlegthwlt/titlegtltBODYgt
  HELLO WORLD lt/BODYgt lt/htmlgt

6
Running XSLT

• To see the output in an XSL ready browser
• Add a processing instruction to the XML with a
  reference to the stylesheet (xsl or css --- basic
  syntax is the same).
• BridgeOfDeath.xml
• lt?xml version"1.0" encoding"UTF-8"?gt
• lt?xml-stylesheet hreffoo.xsl typetext/xsl?gt
• ltepisodegt
• ltdialog speaker"Bridgekeeper"gtStop! Who would
  cross the Bridge of Death must answer me these
  questions three, ere the other side he
  see.lt/dialoggt
• lt/episodegt
• For NetScape 6.0/6.2
• Make sure the mime type returned from the HTTP
  server is text/xml
• For both .xml and .xsl files
• NetSccape correctly looks for this, MSIE does notg

7
XSL apply-templates

• ltxslapply-templates /gt continue processing my
  
• children by applying templates to them.

To understand this, always imagine the xslt
transformer traversing the document in a
depth-first fashion and outputting the text
it encounters until it reaches a rule that
specifies it do otherwise. When a rule is reached
for a particular node in the xml file,
whatever is specified in the rule is carried out,
and then the transformer would go on the the next
node unless there is an embedded
ltxslapply-templatesgt command
8
xsltemplate

• The template is the basis of the rule-based
  architecture that XSLT uses.  
• You define the template to produce an outcome, so
  whenever you call that template (using
  xslapply-templates or xslcall-template), it
  handles this output.
• The template is processed either by its match or
  name attributes.  
• The match attribute uses a pattern, 
• The name is whatever name you give it.
• Another important attribute of the template is
  the mode attribute.  If you want different
  formatting from the general template that you
  have defined, you can define different modes for
  that node, which will ignore the general match
  instruction.
• Note You need to have at least one template in
  your XSLT file.

9
Xslapply-template

• The apply-template element is always found inside
  a template body.  
• It defines a set of nodes to be processed.  In
  this process, it then may find any 'sub' template
  rules to process (child elements of element in
  context).
• If you want the apply-template instruction to
  only process certain child elements, you can
  define a select attribute, to only process
  specific nodes.  In the following example, we
  only want to process the 'name' and 'address'
  elements in the root document element
• ltxsltemplate match"/"gt    ltxslapply-templates
  select"person/name person/address"/gtlt/xsltemp
  lategt

10
XSL apply-templates

• foo2.xsl
• lt?xml version"1.0"?gt
• ltxslstylesheet
• xmlnsxsl"http//www.w3.org/1999/XSL/Transform"
• version"1.0"gt
• ltxsltemplate match/gt
• ltHTMLgtltBODYgt ltxslapply-templates /gt
  lt/BODYgtlt/HTMLgt
• lt/xsltemplategt
• ltxsltemplate matchepisodegt
• ltPgtltIgtI have hit the top-level episode
  elementlt/Igtlt/Pgt
• ltxslapply-templates /gt
• lt/xsltemplategt
• ltxsltemplate matchdialoggt
• ltPgtI have hit some dialoglt/Pgt
• lt/xsltemplategt
• ltxsltemplate matchactiongt

At the beginning output these tags and leave . .
a hole to wait for the stuff you put in between
them. Fill that hole by matching .
further templates against subelements of the
root.
All xsl commands start with xsl
An XSL stylesheet has to be well-formed XML
11
XSLvalue-of

• ltxslvalue-of selectnodeinfogt output a string
  that is derived from the node represented by
  nodeinfo.
• ltxslvalue-of select.gt output the value of
  this node for an element, this will be cdata
  inside of it.
• ltxslvalue-of select_at_speakergt output the
  value of the speaker attribute.

12
XSLvalue-of

• foo3.xsl
• lt?xml version"1.0"?gt
• ltxslstylesheet xmlnsxsl"http//www.w3.org/1999/
  XSL/Transform" version"1.0"gt
• ltxsltemplate match"/"gt
• ltHTMLgtltBODYgt ltxslapply-templates /gt
  lt/BODYgtlt/HTMLgt
• lt/xsltemplategt
• ltxsltemplate match"dialog"gt
• ltPgt
• ltxslvalue-of select"_at_speaker /gt
• ltIgt ltxslvalue-of select". /gt lt/Igt
• lt/Pgt
• lt/xsltemplategt
• ltxsltemplate match"action"gt
• ltPgt ltBgt ltxslvalue-of select"."/gt lt/Bgt lt/Pgt
• lt/xsltemplategt
• lt/xslstylesheetgt

13
XSL Document Structure
lt?xml version1.0?gt ltxslstylesheetgt
ltxsltemplate match/gt
action lt/xsltemplategt
ltxsltemplate matchDialoggt
action lt/xsltemplategt
ltxsltemplate matchActiongt
action lt/xsltemplategt
... lt/xslstylesheetgt
14
Select Attributes and Xpath

• The apply-templates tag takes a Select attribute,
  as do several other tags (e.g. for-each).
• Every Select attribute will takes as a value an
  Xpath expression
• Xpath expressions
• Find nodes (elements or attributes in the input
  document).
• Can select specific children
• ltxsltemplate matchEpisode"gt
  ltxslapply-templates selectDialog_at_speake
  rKing Arthur'"/gtlt/xsltemplategt
• By default, the pattern is always applied
  starting at the node matching the template (i.e.
  we work down the tree)

15
XSLT Outline

• Language for transforming XML to XML
• Components of the XSLT Language
• Control structures
• ltxslapply-templates selectexpressiongt
• ltxslchoose gt
• Commands for creating new tags in the output
• ltxslvalue-of selectexpression/gt
• Xpath expression language for selecting
  attributes and elements
• Miscellaneous other stuff

16
Control Structures Conditionals

• Two basic conditional types.
• First is ltxslchoosegt which is like a switch
• ltxslchoose gt
• ltxslwhen testexpressiongt
• lt/xslwhengt
• ltxslotherwisegt
• lt/xslotherwisegt
• lt/xslchoosegt
• Theres also a simpler form ltxslifgt
• ltxslif testexpressiongt
• Stuff
• lt/xslifgt
• ltxslif test_at_salary gt 200000/gt
• High-Salaried Employee!
• lt/xslifgt

17
xslapply-templates

• With no SELECT block, just says apply any
  templates to my children continue moving down the
  tree.
• What if I say to apply templates to some element,
  and that element has no template?
• lt?xml version"1.0"?gt
• ltxslstylesheet xmlnsxsl"http//www.w3.org/1999/
  XSL/Transform" version"1.0"gt
• ltxsltemplate match/gt
• ltHTMLgtltBODYgt ltxslapply-templates /gt
  lt/BODYgtlt/HTMLgt
• lt/xsltemplategt
• ltxsltemplate matchepisodegt
• ltPgtltIgt Ive hit the top-level episode element
  lt/Igtlt/Pgt
• ltxslapply-templates /gt
• lt/xsltemplategt
• lt!-- Forgot the dialog template --gt
• ltxsltemplate matchactiongt
• ltH2gt Ive hit some action lt/H2gt
• lt/xsltemplategt

18
xslapply-templates

• If there is no SELECT block, it means to apply
  any templates to the children (continue moving
  down the tree.)
• What if I say to apply templates to some element,
  but that element has no template?
• Apply the default template see the example on
  the web for details.

19
Priority

• Suppose more than one template matches?
• XSLT has a way of assigning priorities to
  templates
• It picks the highest-priority match.
• The most specific expression has highest
  priority.
• ltxsltemplate matchArticlegt
• Special treatment for article here!
• lt/xsltemplategt
• ltxsltemplate matchgt
• Heres stuff we do for anything that isnt
  special
• lt/xsltemplategt

20
ltxslapply-templatesgt

• Select doesnt have to move down the tree.
• lt?xml version"1.0"?gt
• ltxslstylesheet xmlnsxsl"http//www.w3.org/1999/
  XSL/Transform" version"1.0"gt
• ltxsltemplate match/gt
• ltHTMLgtltBODYgt
• ltxslapply-templates selectHTML/BODY /gt
• lt/BODYgtlt/HTMLgt
• lt/xsltemplategt
• ltxsltemplate matchBODYgt
• This is the text that is part of the document
• ltxslapply-templates select/HTML/HEAD /gt.
• lt/xsltemplategt
• ltxsltemplate matchHEADgt
• ltfont colorredgt
• ltxslvalue-of selectTITLEgt
• lt/fontgt
• lt/xsltemplategt

Jumps back to the HEAD element.
21
vNamed Templates

• Can also give a template a name
• ltxsltemplate nameheader gt
• ltH1gt
• The average number of wingbeats per second of a
  laden African Swallow is 5
• lt/H1gt
• lt/xsltemplategt
• One can then call a template by name
• ltxsltemplate match/gt
• ltHTMLgt
• ltBODYgt
• ltxslcall-template nameheader gt
• lt/xslcall-templategt
• lt/BODYgt
• lt/HTMLgt
• lt/xsltemplategt
• Important for reusing code!

22
Parameters

• Think of templates as being equivalent to
  functions.
• Thus, it makes sense to be able to pass arguments
  to templates.
• XSL has a verbose way of doing this
• ltxsltemplate nameemphasizegt
• ltxslparam nametext /gt
• ltxslparam namecolor /gt
• ltfont colorcolorgt
• ltxslvalue-of selecttext /gt
• lt/fontgt
• lt/xsltemplategt
• ltxsltemplate matchTITLEgt
• ltxslcall-template nameemphasizegt
• ltxslwith-param nametext select. /gt
• ltxslwith-param namecolor selectred /gt
• lt/xslcall-templategt
• lt/xsltemplategt

Function Emphasize(text,color)
Emphasize(.,red)
23
Parameters

• Parameters are untyped they could contain
  strings, numbers, booleans, or nodes of the tree.
• Organization.xml
• ltorganizationgt
• ltPREZ fnameDaria/gt
• ltVP fnameQuinn/gt
• lt/organizationgt
• Organization.xsl
• ltxsltemplate nameprocesspersongt
• ltxslparam nameperson/gt
• First Name ltxslvalue-of selectperson/_at_fname
  /gt
• lt/xsltemplategt
• ltxsltemplate matchorganizationgt
• ltxslcall-template nameprocesspersongt
• ltxslwith-param nameperson selectPREZ /gt
• lt/xslcall-templategt
• ltxslcall-template nameprocesspersongt
• ltxslwith-param nameperson selectVP /gt

24
Global Parameters

• If an ltxslparam namemyparam/gt occurs at the
  beginning of the stylesheet (before any
  templates) then myparam is a global parameter.
• A value for myparam should be given on the
  command line
• In Xalan
• java org.apache.xalan.xslt.Process -IN
  episode.xml XSL global.xsl PARAM color red
  OUT globalout.html

25
Variable Element

• Variables are declared and initialized with an
  ltxslvariablegt statement. Two ways to give the
  value
• ltxslvariable nameCE"gtCarl Everettlt/xslvariab
  legt
• ltxslvariable namepresident
  selectorganization/PREZ/gt
• A variable is referenced with varname, like
  parameters
• ltxslvalue-of selectCE"/gt
• ltxslvalue-of selectpresident/_at_fname/gt
• ltxslapply-templates select"PRESIDENT/gt
• Once the value of the variable is set, it cannot
  change
• Can only be used (dereferenced) in attribute
  value templates
• The values of variables declared in a template
  are not visible outside of the template.
• ltxsltemplate match/gt
• ltxslvariable nameCE"gtCarl
  Everettlt/xslvariablegt
• ltxslapply-templates selectPREZ/gt
• ltxslvalue-of selectCE/gt
• lt! Carl Everett will print --gt
• lt/xsltemplategt
• ltxsltemplate matchPREZgt
• ltxslvariable nameCE"gtChris
  Eigemanlt/xslvariablegt

26
Loops

• ltxslfor-each selectexpressiongt
• Block
• lt/xslfor-eachgt
• expression must return some set of nodes in the
  input. Will insert the output of Block into the
  result
• Similar to ltxslcall-templategt, but with no name
  for the template.

27
Controlling Order

• Both xslfor-each and xslapply-templates have as
  default order
• The order in which the matching elements occur
  within the document.
• You can change that order using ltxslsort gt
• ltxslfor-each selectstudentgt
• ltxslsort selectstudidgt
• lt/xslsortgt
• ......
• lt/xslfor-eachgt
• Analagous to SQL order by clause.
• ltxslsort selectstudid orderdescending/gt

28
Mode

• Another way of passing an argument to a template
  is to stick it in a mode attribute
• ltxsltemplate matchHeadgt
• ltxslapply-templates modered /gt
• lt/xsltemplategt
• ltxsltemplate matchBodygt
• ltxslapply-templates modeblue /gt
• lt/xsltemplategt
• ltxsltemplate match modeblue gt
• ltfont colorbluegtltxslvalue-of select.
  /gt lt/fontgt
• ltxslapply-templates modeblue /gt
• lt/xsltemplategt
• ltxsltemplate match modered gt
• ltfont colorredgt ltxslvalue-of select.
  /gtlt/fontgt
• ltxslapply-templates modeblue /gt
• lt/xsltemplategt

Useful to control priority between two templates
that match the same tag.
29
XSLT Outline

• Language for transforming XML to XML
• Components
• Control structures
• Commands for creating new tags in the output
• Xpath expression language
• Miscellaneous other stuff

30
Creating New Elements

• We saw that we can create a fixed tag by just
  writing it inside the template.
• ltxsltemplates match/gt
• ltHTMLgt ltBODYgt Bonjour Monde lt/BODYgt lt/HTMLgt
• ltxslapply-templatesgt
• We also know how to create dynamic text content
  using
• ltxslvalue-ofgt
• Suppose the values of attributes in a tag to
  depend on stuff in the input document
• ltA href article/url gt Go to article lt/Agt
• The bracket says that the stuff inside is to be
  evaluated, not written out literally.

31
Creating New Elements

• Suppose the name of the attribute depends on the
  document?
• ltxslattribute namesomeexpression gt
• lt! Whatever is computed here is the value
  --gt
• lt/xslattributegt
• ltxslattribute namemyname gt
• ltxslvalue-of selectmyvalue /gt
• lt/xslattributegt
• Can do the same thing to create a new element
• ltxslelement namesomethinggt
• ltxslattribute namemyattnamegt
• lt/xslattributegt
• lt/xslelementgt

32
Copying nodes

• Sometimes you just want to simply copy part of
  the input document
• to the output.
• You can do this quickly with ltxslcopygt and
  ltxslcopy-ofgt
• ltxsltemplate matchULgt
• ltxslcopy-of select. /gt
• lt!-- this will copy the OL tag and all of its
  subelements verbatim--gt
• lt/xsltemplategt
• ltxsltemplate matchOLgt
• ltxslcopy /gt
• lt!-- this will copy the OL tag but leave all of
  its subelements out --gt
• lt/xsltemplategt
• Note ltxslcopy /gt copies the current node
  (although there is a way to add stuff inside
  xslcopy to get different behavior). But
• ltxslcopy-of gt expects a selectexpression
  argument, and copies the result of expression.

33
XSLT Outline

• Language for transforming XML to XML
• Components
• Control structures
• Commands for creating new tags in the output
• Xpath expression language
• Overview
• Node-sets, axes, and predicates
• Node-set operators and functions
• Built-in Functions
• Multiple Documents
• Match expressions
• Miscellaneous other stuff
• Namespaces
• XML-schema

34
XPath

• A language for identifying stuff within a
  document.
• Xpath expressions can return
• Bunch of stuff within the document a nodeset
• True/false, Number(s), String(s)
• Used by other XML specifications
• XPointer, XQL, XSLT.
• In XSLT, it is used
• in select attribute values
• in other places (e.g. the test attribute of an
  xslwhen and xslif)
• Examples
• ltxslapply-templates selectCHAPTERgt
• ltxslvalue-of selectchapter/_at_numbergt
• ltxslvalue-of selectname(..)gt

35
Navigating the Tree

• Simple Xpath expressions consist of a navigation
  path.
• ltxslapply-templates selectCHAPTER/VERSEgt
• ltxslfor-each selectCHAPTER/VERSE/LINEgt
• When used in XSLT, this XPATH expression
• takes as input the current node
• the node that we are processing at that point in
  the XSLT transformation
• returns the set of elements that are VERSE
  subelements of CHAPTER subelements of the node.
• The above are examples of relative paths. One can
  also have an absolute path.
• ltxslapply-templates select/CHAPTER/VERSEgt
• Rough idea of navigation pathssimilar to Unix
  path names.
• ./CHAPTER any CHAPTER child of mine. (same as
  CHAPTER)
• .//CHAPTER any CHAPTER child of some child of
  mine.
• ../CHAPTER any CHAPTER child of my parent.

36
Navigation Paths

• On the other hand..bet you cant do this in Unix
  (but can in Xpath)
• .//CHAPTER any CHAPTER descendant
  of the current node. (be careful this is
  powerful but potentially inefficient!)
• /CHAPTER//VERSE any VERSE that is a
  descendant of some CHAPTER child of the root
  node.
• But XPATH allows you to select not just element
  nodes of the input, but attributes also.
• ltxslfor-each selectepisode/dialog/_at_speakergt
• ltxslvalue-of select//comment() /gt
• lt!- Will match every comment in the document
• So, puts the content of every comment each
• time any speaker attribute is found --gt
• lt/xslfor-eachgt

37
ChangeDialogToCommentValue.xsl

• lt?xml version"1.0" encoding"UTF-8"?gt
• ltxslstylesheet version"1.0" xmlnsxslhttp//www
  .w3.org/1999/XSL/Transform xmlnsfo"http//www.w3
  .org/1999/XSL/Format"gt
• ltxsltemplate match"/"gt
• ltHTMLgtltBODYgt
• ltxslfor-each select"episode/dialog
  /_at_speaker"gt
• ltxslvalue-of select"//comment()"
  /gt
• lt!-- Will match every comment in
  the document --gt
• lt/xslfor-eachgt
• lt/BODYgtlt/HTMLgt
• lt/xsltemplategt
• lt/xslstylesheetgt

38
Dialog to Comment

• BridgeOfDeathEpisodeDialogToComment.xml
• lt?xml version"1.0" encoding"UTF-8"?gt
• lt!-- BridgeOfDeathEpisodeDialogToComment.xml --gt
• lt?xml-stylesheet hrefChangeDialogToComment.xsl
  typetext/xsl?gt
• ltepisodegt
• ltdialog speaker"Bridgekeeper"gtStop! Who would
  cross the Bridge of Death must answer me these
  questions three, ere the other side he
  see.lt/dialoggt
• ltdialog speaker"Sir Launselot"gtAsk me the
  questions, bridgekeeper. I am not
  afraid.lt/dialoggt
• Output
• ltHTML xmlnsfo"http//www.w3.org/1999/XSL/Format"
  gtltBODYgt BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  BridgeOfDeathEpisodeDialogToComment.xml
  lt/BODYgtlt/HTMLgt

39
Abbreviate

• Many XPath expressions are actually abbreviations
• ./CHAPTER is an abbreviation for childCHAPTER
• DIALOG/_at_speaker abbreviates childDIALOG/attribut
  espeaker
• ./_at_speaker abbreviates attributespeaker
• We will generally use the short name whenever
  possible.

40
The Full Tree
/
Think of an Xpath expression as working on a tree
that shows all the information in the
XML document (this tree is called the InfoSet of
the document)

• episode

dialog
action
speaker BridgeKeeper
A giant unseen hand pick up Robin and casts
him into the gorge
What is your favorite color?
Every node has a Type (element, attribute,
Comment,processing-instruction, text), and either
a Name (dialog, episode) or a Value
(BridgeKeeper,What is your)
41
Location Path

• You can use Xpath to get to various features of a
  node
• ltxslvalue-of selectname(.)gt
• ltxslapply-templates selectprocessing-instructio
  n()comment()/gt
• ltxsltemplate matchprocessing-instruction()comm
  ent()gt
• You can also do things like
• ltxslvalue-of selectname(..)gt
• ltxslvalue-of selectname(preceding-sibling(.))/
  gt

42
Predicates

• In addition to a location path, you might want to
  restrict to nodes that satisfy certain additional
  conditions
• Predicate filter is used to narrow down the list
• Predicate is held between ' '
• Examples
• //dialog_at_speakerKing Arthur
• All dialog elements anywhere in the document
  spoken by King Arthur.
• student_at_e-mail
• All student subelements of the current node that
  have an e-mail address
• courses/course_at_year2001 and
  _at_semesterspring
• All course elements that are subelements of a
  courses subelement of the current node
• And which are for spring 2001
• /courses/courseposition()2
• The second course grandchild of the root.

43
More Filters
ltxslapply-templates selectdialog_at_speakerspea
kernamegt Apply templates to any dialog
children of the current node whose speaker is the
variable speakername ltxslfor-each
selectcalendarperson/_at_handlevarun/activity
date/_at_month3gt . ltxslvalue-of select
./_at_description/gt lt! Will print out the
description of the activity --gt lt/xslfor-eachgt
For every calendar item subelement of the
current node for every person whose handle is
varun grab any activity they did in month 3, and
do the following (print out description of the
activity.
44
Multi-step Xpath

• Can continue on after a predicate test
• student_at_lnamegt c/address/city
• cities of all students whose last name is above c
  in the alphabet
• (student_at_lnamegt c)position()1
• The first student whose name is above c in the
  alphabet
• student _at_lnamename/_at_
• All attributes of the student whose last name
  matches the variable (or parameter) name

45
Multi-step Xpath

• ltxsltemplate matchuniversitygt
• ltxslfor-each selectenrollment/classcount(./stu
  dent)5 gt
• ltxslvalue-of select.gt
• Note that . here means the class. . normally
  stands for the context node, which changes with
  each step of the multi-step evaluation process.
• Compare this with
• ltxsltemplate matchuniversitygt
• ltxslfor-each select enrollment/classcount(./s
  tudent) count(current()/student gt

46
Using with Transformer
TransformerFactory tFactory TransformerFactory.n
ewInstance() String stylesheet
"prices.xsl" String sourceId "newXML.xml"
File pricesHTML new File("pricesHTML.html")
FileOutputStream os new FileOutputStream(prices
HTML) Transformer transformer   
tFactory.newTransformer(new StreamSource(styleshee
t)) transformer.transform(new
StreamSource(sourceId),
new StreamResult(os))