W3C XML XSLT. Jaroslav Porubän 2008

Transcription

1 XSLT Jaroslav Porubän 2008

2 XSL Overview extensible Stylesheet Language A language for expressing stylesheets Made of two parts XSL Transformation (XSLT) XSL Formatting Objects (XSL-FO)

3 XSLT - Transformation language for transformation Transforming document into Another document XHTML WML HTML document Text

4 Importance of Transformation Presentation Oriented Publishing document separates content from presentation Transformations can be used to style documents (HTML + CSS) Message Oriented Middleware Different content model Different structural relationship Different vocabularies

5 XSLT Operational Model XSLT Processor INPUT XSL Stylesheet... <xsl:template match="title"> <H3> <xsl:apply-templates/> </H3> <HR/>... OUTPUT HTML XHTML WML text

6 XSLT Processor Piece of software Reads an XSLT stylesheet and input document Converts the input document into an output document According to the instruction given in the stylesheet Called stylesheet processor

7 Example - <people> <person born="1912" died="1954"> <name> <first_name>alan</first_name> <last_name>turing</last_name> </name> <profession>computer scientist</profession> <profession>mathematician</profession> <profession>cryptographer</profession> </person> <person born="1918" died="1988"> <name> <first_name>richard</first_name> <middle_initial>m</middle_initial> <last_name>feynman</last_name> </name> <profession>physicist</profession> <hobby>playing the bongoes</hobby> </person> </people>

8 Example stylesheet 0 <xsl:stylesheet version="1.0" xmlns:xsl=" "> </xsl:stylesheet> Applying empty stylesheet to any document Elements are traversed sequentially Content of each element is put in output Attributes are not traversed Without any specific templates XSLT processor falls back to default behavior

9 xsl:template Element Controls which output is created from which input match attribute contains an XPath expression XPath expression identifies input node set it matches For each node in the node set, the template contents (things between xsl:template tags) are instantiated and inserted into the output tree

10 Example stylesheet 1 <xsl:stylesheet version="1.0" xmlns:xsl=" form"> <xsl:template match="people"> </xsl:stylesheet>

11 Example stylesheet 2 <xsl:stylesheet version="1.0" xmlns:xsl=" m"> <xsl:template match="people"> Some people are here. </xsl:stylesheet>

12 Example stylesheet 3 <xsl:stylesheet version="1.0" xmlns:xsl=" m"> <xsl:template match="person"> A Person </xsl:stylesheet> Whitespace outside of <person> element preserved <person> element is replaced by contents of the template

13 Example stylesheet 4 <xsl:stylesheet version="1.0" xmlns:xsl=" form"> <xsl:template match="person"> <p>a Person</p> </xsl:stylesheet>

14 xsl:value-of Element Extracts the string value of an element or an attribute and writes it to output text content of the element after all the tags have been removed and entity references are resolved select attribute containing XPath expression identifies an element or an attribute It could be a node set, in which case, the string value of first node is taken

15 Example stylesheet 5 <xsl:stylesheet version="1.0" xmlns:xsl=" form"> <xsl:template match="person"> <p> <xsl:value-of select="name"/> </p> </xsl:stylesheet>

16 xsl:apply-templates Element This element applies a template to the current element or to the current element's child nodes If we add a select attribute to the <xsl:apply-templates> element, it will process only the child element that matches the value of the attribute

17 Example stylesheet 6 <xsl:stylesheet version="1.0" xmlns:xsl=" form"> <xsl:template match="person"> <p> <xsl:value-of select="name"/> </p> </xsl:stylesheet>

18 Example stylesheet 7 <xsl:stylesheet version="1.0" xmlns:xsl=" <xsl:template match="name"> <xsl:value-of select="last_name"/>, <xsl:value-of select="first_name"/> <!-- Apply templates only to name children --> <xsl:template match="person"> <xsl:apply-templates select="name"/> </xsl:stylesheet>

19 Example stylesheet 8 <xsl:stylesheet version="1.0" xmlns:xsl=" "> <xsl:template match="people"> <html> <head><title>famous Scientists</title></head> <body> <xsl:apply-templates/> </body> </html> <xsl:template match="person"> <xsl:apply-templates select="name"/> <xsl:template match="name"> <p><xsl:value-of select="last_name"/>, <xsl:value-of select="first_name"/></p> </xsl:stylesheet>

20 Example stylesheet 9 <xsl:stylesheet version="1.0" xmlns:xsl=" <xsl:template match="people"> <html> <head><title>famous Scientists</title></head> <body> <dl> <xsl:apply-templates/> </dl> </body> </html> <xsl:template match="person"> <dt><xsl:apply-templates select="name"/></dt> <dd><ul> <li>born: <xsl:apply-templates select="@born"/></li> <li>died: <xsl:apply-templates select="@died"/></li> </ul></dd> </xsl:stylesheet>

21 Modes Same input content needs to appear multiple times in the output document formatted according to different templates Titles of chapters Table of contents In the chapters themselves mode attribute xsl:template xsl:apply-templates

22 Example stylesheet 10 <xsl:template match="people"> <html> <head><title>famous Scientists</title></head> <body> <ul> <xsl:apply-templates select="person" mode="toc"/> </ul> <xsl:apply-templates select="person"/> </body> </html> <!-- Table of Contents Mode Templates --> <xsl:template match="person" mode="toc"> <xsl:apply-templates select="name" mode="toc"/> <xsl:template match="name" mode="toc"> <li><xsl:value-of select="last_name"/>, <xsl:value-of select="first_name"/></li>

23 Filtering Filtering can be done using XPath predicates

24 Example stylesheet 11 <xsl:stylesheet version="1.0" xmlns:xsl=" form"> <xsl:template match="person"> <xsl:apply-templates select="*[not(self::hobby)]"/> </xsl:stylesheet>

25 xsl:for-each Element The XSL <xsl:for-each> element can be used to select every element of a specified node-set Iterating through a node set The value of the select attribute is an XPath expression

26 Example stylesheet 12 <xsl:stylesheet version="1.0" xmlns:xsl=" XSL/Transform"> <xsl:template match="people"> <xsl:for-each select="person"> <xsl:value-of select="name"/> <xsl:value-of </xsl:for-each> </xsl:stylesheet>

27 xsl:if Element Tests content for certain values <xsl:if test=xpath>... </xsl:if> The test attribute is required, the value is an XPath expression

28 Example stylesheet 13 <xsl:stylesheet version="1.0" xmlns:xsl=" form"> <xsl:template match="people"> <xsl:for-each select="person"> <xsl:value-of select="name"/> <xsl:if Died in <xsl:value-of </xsl:if> </xsl:for-each> </xsl:stylesheet>

29 xsl:choose Element Testing agains multiple values <xsl:choose> <xsl:when test=xpath> </xsl:when> <xsl:when test=xpath> </xsl:when>... <xsl:otherwise> </xsl:otherwise> </xsl:choose> The test attribute is required, the value is an XPath expression

30 Example stylesheet 14 <xsl:stylesheet version="1.0" xmlns:xsl=" <xsl:template match="people"> <xsl:for-each select="person"> <xsl:value-of select="name"/> <xsl:choose> <xsl:when Died in <xsl:value-of </xsl:when> <xsl:otherwise> Did not born in 1912 </xsl:otherwise> </xsl:choose> </xsl:for-each> </xsl:stylesheet>

31 xsl:sort Element XSLT provides a nice way to sort documents by element contents <xsl:sort select=selection> </xsl:sort> Sorting can only be done in the following constructs <xsl:apply-templates /> <xsl:for-each />

32 Example stylesheet 15 <xsl:stylesheet version="1.0" xmlns:xsl=" 999/XSL/Transform"> <xsl:template match="people"> <xsl:apply-templates> <xsl:sort select="name"/> </xsl:apply-templates> </xsl:stylesheet>

33 Example stylesheet 16 <xsl:stylesheet version="1.0 xmlns:xsl=" 999/XSL/Transform"> <xsl:template match="people"> <xsl:apply-templates> <xsl:sort select="name" order="descending" / > </xsl:apply-templates> </xsl:stylesheet>

34 xsl:copy Element Used for creating an Document The copying is done using this construct: <xsl:copy></xsl:copy> We will also specify to the processor that our output should be instead of HTML <xml:output method="xml"/>

35 Example stylesheet 17 <xsl:stylesheet version="1.0" xmlns:xsl=" SL/Transform"> <xsl:output method="xml"/> <xsl:template match="people"> <xsl:copy> <xsl:apply-templates> <xsl:sort select="name"/> </xsl:apply-templates> </xsl:copy> </xsl:stylesheet>

36 Example stylesheet 18 <xsl:stylesheet version="1.0" xmlns:xsl=" SL/Transform"> <xsl:output method="xml"/> <xsl:template match="*"> <xsl:copy> <xsl:apply-templates> <xsl:sort select="name"/> </xsl:apply-templates> </xsl:copy> </xsl:stylesheet>

37 xml-stylesheet Processing Instruction <?xml version="1.0" encoding="utf-8"?> <?xml-stylesheet type="text/xsl" href="nakup.xsl"?> <nakup> <osoba meno="jano"> <polozka>chlieb</polozka> <polozka>sunka</polozka> <polozka>maslo</polozka> </osoba> <osoba meno="mara"> <polozka>paradajka</polozka> <polozka>mlieko</polozka> </osoba> </nakup>