Converting XMLFiles with XSLT and XPath

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Converting XML-Files with XSLT and XPath
XSLT eXtensible Stylesheet Language
Transformations Version 1.0 XPath eXtensible
Path Language Version 1.0

• Karsten Ehrig

PetriNet-AG GraGra-AG 2001
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Outline of the Talk

• Motivation
• XML Overview
• Features of XPATH
• Features of XSLT
• Converting XML-Files with XSLT and XPath
• Using XSLT and XPATH with Java
• Example PNML 1.0 ? GTS 1.0
• Summary and Outlook

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Motivation

• Graph Transformation System (GTS)
• GenGEd, AGG (TU-Berlin)
• Petri Net Markup Language (PNML)
• Petri-Net-Kernel (PNK) (HU-Berlin)
• Problem Creating a Converting-Tool

GenGEd
PNK
Convert
Xml-Files to GTS.dtd
Xml-Files to stNet.xsd
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XML Overview

• strict syntax rules
• additional syntax rules Document Type
  Definitions (DTDs), XMLSchema
• structured interchange facilities for documents
• replaces ASCII
• tree-like structured documents
• also usable for interchanging data structures
• more and more standard for exchange formats
• comes up with a lot of tool support

http//www.w3.org/TR/REC-xml
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XML Grammars Document Type Definition (DTD) and
XMLSchema

• Document Type Definition (DTD)
• defines a concrete syntax for elements and
  attributes in a xml-file
• the DTD-syntax is not xml-based
• limited possibilities to define abstract data
  types
• XMLSchema
• syntax is xml-based
• allows redefinitions of data types
• allows conditions for elements and attributes
• allows the use of all primitive data types
• e.g. integer and float

http//www.w3.org/1999/XMLSchema
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XML Overview A simple XML-File
lt?xml version1.0?gt lt!DOCTYPE user SYSTEM
user.dtdgt ltuser id007gt ltnamegtRoger
Moorelt/namegt ltemailgtmoore_at_cinema.uklt/emailgt lt/use
rgt

• Basic Concepts
• Logically and physically structured documents
• tree-like structure
• each tree node has
• start tag
• end tag
• set of subtags
• set of attributes

Based on the DTD
lt!ELEMENT user (name, email?)gt lt!ATTLIST user
id ID
REQUIREDgt lt!ELEMENT name (PCDATA)gt lt!ELEMENT
email (PCDATA)gt
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XSL (XSLT, XPath) Overview

• XSL (eXtensible Stylesheet Language) is a
  xml-based language for transforming xml-documents
  to other xml-documents (e.g. based on another
  DTD), html, text-files or other types of
  documents
• XSL contains the languages
• XPath expressions for selecting elements in a
  document
• XSLT (XSL Transformations)
• other languages e.g. XLink, XPointer, ...

http//www.w3.org/TR/xsl
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Features of XPath

• identifies particular parts in XML documents
• Expressions along the tree structure of XML
  documents
• Examples
• childchapter
• Selects all subordinated elements of chapter
• childselfchapter
• Selects all chapter elements of the context
  element
• id(a23)/childchapterposition()5
• Selects the fifth child-element with the name
  chapter of the element with the unified ID a23

http//www.w3.org/TR/xpath
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Features of XSLT (XSL Transformations)

• tree-oriented transformation language based on
  XML
• uses XPath expressions for
• conditional parsing if / while / test / ...
• selecting parts of the document match / select /
  value-of / template / ...
• manipulation of strings and numbers
• vocabulary for specifying formating e.g. sorting
• variable output formats e.g. xml, html, plain
  text, ...

http//www.w3.org/TR/xslt
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Converting XML-Files with XSLT and XPath
Output
Converting Rules Stylesheet (XSL)
XSLT (eXtensible Stylesheet Language
Transformations)
XML-File (Out-DTD)
XPath
HTML
Input
XSLT-Engine based on Java
XML-File (Input-DTD)
Plain Text
...
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Example of a Stylesheet (XSL) Transformation
With stylesheet (xsl)
ltxsltemplate matchusergt ltmeetinggt ltxslvalue-o
f selectnamegt lt/meetinggt ltcontactgt ltxslvalue-o
f selectemailgt lt/contactgt lt/xsltemplategt
Converts
lt?xml version1.0?gt lt!DOCTYPE user SYSTEM
user.dtdgt ltuser id007gt ltnamegtRoger
Moorelt/namegt ltemailgtmoore_at_cinema.uklt/emailgt lt/use
rgt
ltmeetinggtRoger Moorelt/meetinggt ltcontactgtmoore_at_cine
ma.uklt/contactgt
To
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Java API for XML Parsing (jaxp Vers. 1.1)

• DOM (Document Object Model) Parser
• useful to verify a xml-file according to a DTD
  e.g. tfs/tools/showXML - Tool
• SAX (Simple API for XML) Parser
• Interface for event-based parsing of XML
  documents
• Transformation Factory
• new feature in version 1.1
• XML Inputfile
• Converting-Rules XSL-File with XPath Rules
• Output XML (Out-DTD) / HTML / Text / ...

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Example PNML 1.0 ? GTS 1.0

• Petri-Net-Markup-Language Vers. 1.0 ? Graph
  Transformation System Vers. 1.0
• Java Petri-Net-Kernel (alpha-Version) of the
  HU-Berlin could export place transition nets in
  PNML 1.0 based on the XMLSchema stNet.xsd
• Converting Tool at
• tfs/tools/XMLConv
• gt pnml2gts.sh ltinputfilegt ltoutputfilegt
• Output xml-file based on the GTS-DTD
• old version with EdgeType and NodeType
• Problem New GTS-DTD (changed for AGG) which
  doesnot work with GenGEd

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Example PNML 1.0 ? GTS 1.0 stNet.xsd

• lt?xml version"1.0" encoding"UTF-8"?gt
• lt!DOCTYPE xsdschema PUBLIC "-//W3C//DTD
  XMLSCHEMA 19991216//EN" ""
• lt!ENTITY p 'xsd'gt
• lt!ENTITY s 'xsd'gt
• gt
• ltxsdschema xmlnsxsd"http//www.w3.org/1999/XMLS
  chema"gt
• ltxsdannotationgt
• ltxsddocumentationgt
• Proposal Petri Net Markup Language
  schema for st-Nets
• Matthias Juengel 12.10.2000
• Michael Weber 12.10.2000
• lt/xsddocumentationgt
• lt/xsdannotationgt
• ...
• ...

file//tfs/tools/XMLConv/stNet.xsd
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Example PNML 1.0 ? GTS 1.0 gts.dtd (old
version)
lt!ELEMENT GraphTransformationSystem
(TaggedValue?, ((Types?,Graph,Rule,TaggedValue?
) Module))gt lt!ATTLIST GraphTransformationSystem
name NMTOKEN REQUIREDgt lt!-- Type
Declarations --gt lt!ELEMENT Types
(NodeType,EdgeType)gt lt!ELEMENT NodeType
(TaggedValue?, AttrType, NodeTypeLayout?)gt
lt!-- TaggedValues could be derived attributes,
etc --gt lt!ATTLIST NodeType id ID
REQUIRED name NMTOKEN
REQUIREDgt lt!ELEMENT EdgeType (TaggedValue?,
AttachName, AttrType, EdgeTypeLayout?)gt
lt!-- TaggedValues could be multiplicities,
rolenames, etc.--gt lt!ATTLIST EdgeType
id ID REQUIRED name
NMTOKEN REQUIRED source IDREFS
IMPLIED target IDREFS IMPLIEDgt
file//tfs/tools/XMLConv/gts.dtd
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Example PNML 1.0 ? GTS 1.0 ProducerConsumerSyst
em.xml
lt?xml version"1.0" encoding"UTF-8"?gt ltpnml
xmlnsxsi"http//www.w3.org/1999/XMLSchema-instan
ce" xsinoNamespaceSchemaLocation"stNet.xsd"gt ltne
t id"n1" type"stNet"gt ltplace id"p1"gt
ltnamegt ltvaluegtready to producelt/valuegt lt/namegt
ltinitialMarkinggt ltvaluegt1lt/valuegt
lt/initialMarkinggt lt/placegt lttransition
id"t1"gt ltnamegt ltvaluegtproducelt/valuegt
lt/namegt lt/transitiongt ltarc id"a1"
source"p1" target"t1"gt ... lt/arcgt ...
p1
a1
t1
file//tfs/tools/XMLConv/ProducerConsumerSystem.x
ml
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Example PNML 1.0 ? GTS 1.0 Stylesheet
pnml2gts.xsl part 1
... ltxsltemplate match"place"gt ltNode
type"IDplace" id"ID_at_id"gt ltAttribute
name"PlaceName" type"IDpn"gt ltattrvalgt
ltxslvariable name"string-value"
select"name/value"/gt ltPrimitiveValue
value"string-value" type"String"
id"IDpnV_at_id"/gt lt/attrvalgt
lt/Attributegt lt/Nodegt ltxslif
test"initialMarking"gt ltNode type"IDtoken"
id"IDTok_at_id"/gt lt/xslifgt lt/xsltemplategt ...
file//tfs/tools/XMLConv/pnml2gts.xsl
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Example PNML 1.0 ? GTS 1.0 Stylesheet
pnml2gts.xsl part 2
... ltxsltemplate match"arc"gt ltxslvariable
name"source" select"_at_source"/gt ltxslvariable
name"target" select"_at_target"/gt ltxslif
test'../transition_at_idsource and
../place_at_idtarget'gt ltEdge
target"IDtarget" source"IDsource"
type"IDarcTP id"ID_at_id"/gt lt/xslifgt
ltxslif test'../place_at_idsource and
../transition_at_idtarget'gt ltEdge
target"IDtarget" source"IDsource"
type"IDarcPT" id"ID_at_id"/gt
lt/xslifgt lt/xsltemplategt ...
file//tfs/tools/XMLConv/pnml2gts.xsl
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Example PNML 1.0 ? GTS 1.0 Outputfile conv.xml
... ltNode id"IDp1" type"IDplace"gt
ltAttribute type"IDpn" name"PlaceName"gt
ltattrvalgt ltPrimitiveValue
id"IDpnVp1" type"String" value"ready to
produce"/gt lt/attrvalgt
lt/Attributegt lt/Nodegt ... ltEdge id"IDa1"
type"IDarcTP" source"IDp1" target"IDt1"/gt ...
file//tfs/tools/XMLConv/conv.xml
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Summary and Outlook

• Universal XML Converting Tool tfs/tools/XMLConv
• Outlook
• Creating an universal PNML / GTS tool working in
  both directions
• Improving GenGEd to import / export all types of
  Petri-Nets in GTS-Format
• Animation of Petri-Nets in GenGEd