Overview
* XSL stands for EXtensible Stylesheet Language.
* XSLT stands for XSL Transformations
* XSLT transforms an XML document into another XML document
* XSLT uses XPath to navigate in XML documents
* XSLT is a W3C Recommendation
Top Level Elements
xlt:import and xlt:include
* Both reference another style sheet.
* Style sheet imported with xlt:import has lower priority so current style sheet can override imported style sheet.
* xlt:import can only appear at the beginning of style sheet.
xlt:strip-space and xlt:preserve-space
<xsl:strip-space elements="*"/> <xsl:preserve-space elements="greeting salutation"/>
Preserve XML indents
Often times you want to preserve the xml output for readability. Here is how to achieve it.
<xsl:output method="xml" indent="yes"/>xlt:key
xsl:variable
xsl:param
Extend XSLT
You can extend XSLT by
* Extension element
* Extension function
XPath
XPath 2.0
* Everything is sequence.
* Supports atomic values such xs:integer which can not be broken down to smaller parts.
* Supports all build-in data types of XML schema.
XPath Node Types
* The document node
– One per document
– No parent
* Element nodes
* Attribute nodes
* Text nodes
* Comment nodes
* Processing instruction nodes
* Namespace nodes
Node Tests
* node()
– Matches any node.
* text()
– Matches text nodes only.
* comment()
– Matches comment nodes only.
* processing-instruction()
– Matches processing instructions only.
* NCName:*
– Matches all nodes in a particular name space.
XPath 2.0 Node Tests
* element()
– any element
– same as select=”*”
– element(author): matches any element named author.
– element(date-of-birth, xs:gYear): matches any element named date-of-birth with data type of xs:gYear.
– element(*, xs:gYear): matches all elements of data type xs:gYear.
* schema-element(author)
– Matches any element named author which is declared in schema.
* attribute()
– same as select=”@*”
* *:NCName
– Matches all nodes with local name of NCName in any namespace.
* document-node()
– Matches a document node
Output Text
* Use xsl:text for more control over white spaces.
* Use <xsl:value-of select=””/> to output values of something.
<xsl:value-of select="count(/greetings/greeting)"/>Branching
* xsl:if
* xsl:choose
* xsl:for-each
Invoke Template by Name
<xsl:template match="/"> <xsl:call-template name="t2"/> </xsl:template> <xsl:template name="t1" match="greeting"> this is template 1. </xsl:template> <xsl:template name="t2" match="greeting"> this is template 2. </xsl:template>
Template a la Mode
<xsl:template match="/"> <html> <body> A la templates. <xsl:apply-templates select="/greetings/greeting" mode="alat1"/> <xsl:apply-templates select="/greetings/greeting" mode="alat2"/> </body> </html> </xsl:template> <xsl:template mode="alat1" match="greeting"> this is a la template 1. <xsl:value-of select="."/> </xsl:template> <xsl:template mode="alat2" match="greeting"> this is a la template 2. <xsl:value-of select="."/> </xsl:template>
Sample Program To Do XSLT
package testxslt; import java.io.File; import javax.xml.transform.*; import javax.xml.transform.stream.*; public class TestXSLT1 { public TestXSLT1() { } public static void main(String[] args) throws TransformerConfigurationException, TransformerException { TestXSLT1 testxslt = new TestXSLT1(); testxslt.doTransform("HelloWorld.xml","HelloWorld.xsl"); testxslt.doTransform("HelloWorld.xml","HelloWorld2.xsl"); } private void doTransform(String xml, String xsl) throws TransformerException, TransformerConfigurationException { Source xmlSrc = new StreamSource(new File(xml)); Source xsltSrc = new StreamSource(new File(xsl)); Result result = new StreamResult(System.out); TransformerFactory tf = TransformerFactory.newInstance(); Transformer t; t = tf.newTransformer(xsltSrc); t.transform(xmlSrc,result); } }
Examples
* Output Indented XML format
<xsl:output method="xml" indent="yes"/>* Suppress empty and null nodes
<!-- Macro template --> <xsl:template name="writeElement"> <xsl:param name="innode"/> <xsl:param name="outname"/> <xsl:if test="$innode[normalize-space(.) != ''] and $innode/text() != 'NULL'"> <xsl:element name="{$outname}"> <xsl:value-of select="$innode"/> </xsl:element> </xsl:if> </xsl:template> <!-- Use maco template --> <xsl:call-template name="writeElement"> <xsl:with-param name="innode" select="myns:myOriginalNode"/> <xsl:with-param name="outname" select="'myTransformedNode'"/> </xsl:call-template>