XSLT Overview


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XSLT Overview

  1. 1. CIS-189
  2. 2.  XSL stands for Extensible Stylesheet ◦ Stylesheets are used to manage organization and presentation of data Implemented as an XML language ◦ Rules of XML apply Made up of ◦ XSL-FO (Formatting Objects) ◦ XSLT (Transformations)
  3. 3.  XSL-FO focused on presentation to screen and paper ◦ Not well-supported by browsers XSLT emphasizes re-organization of data ◦ Typically used for presentation but can also be used for conversion of data storage format ◦ XSLT is a declarative language  Similar to SQL, describe results not steps
  4. 4.  Cascading Style Sheets used to separate presentation from data XSLT used to change – transform – data ◦ Convert an XML document to XHTML Can use both together
  5. 5. XSL requires several steps1. XML processor reads document ◦ Creates document tree2. XSL processor applies rules from stylesheet ◦ Rules applied to document tree ◦ Rules applied by using pattern matching  Identify nodes to apply rules to ◦ Rules are stored as templates
  6. 6.  XSL works by using an Input Tree ◦ Input Tree comes from XML processor Process of changing input values is call Tree Transformation Result of transformation is the Result Tree ◦ Result Tree can include  XML  HTML (must adhere to XML rules, i.e., XHTML)  Formatting Objects
  7. 7.  Extensible Stylesheet Transformations is method of changing (transforming) XML based on rules of a stylesheet Xpath allows manipulation of parts of XML document ◦ Not XML-based ◦ Provides compact references  Useful in URI’s, attributes ◦ Document must exist as nodes (previously parsed)
  8. 8.  Templates are definitions of rules, organization Patterns define values searching for (where to apply templates) Expressions allow use of functions using nodes as inputs When referring to document attributes preface name with “@”
  9. 9.  <xsl:stylesheet> is root element ◦ Uses namespace to define elements, attributes valid in a stylesheet <xsl:template> defines the rules/ transformations to apply ◦ Match attribute specifies pattern to apply rules to  Functions similar to criteria <xsl:apply-templates> applies the rules defined for a particular element ◦ Select attribute specifies elements to apply to
  10. 10.  <xsl:value-of> returns the value of a specified node, function ◦ Select attribute specifies value source <xsl:copy> copies a node to the result tree without any child nodes or attributes <xsl:copy-of> copies a node and child/attribute nodes <xsl:output> controls the result tree ◦ method=“xml|html|text”
  11. 11.  <xsl:if> provides a boolean test to determine processing <xsl:choose> offers an IF ... THEN ... ELSE construct <xsl:for-each> allows each node in a group to be processed <xsl:sort> specifies order for a group of nodes
  12. 12.  Match can use ◦ node name ◦ current position (represented by “.”) ◦ relative position (for example, parent = “..”) Specifies where the transformation to be applied