Lecture 8 XSL 2206 FIS Nurlan Karimzhan

Applying XSLT Stylesheets to XML Documents • There are three ways of applying an XSLT stylesheet to an XML document: – Directly applying an XSLT processor to the XML document and the XSLT stylesheet, – Calling an XSLT processor from within a (Java) program, – Adding to the XML document a link to the XSL stylesheet and letting the browser do the transformation.

Using an XSL Processor XSL stylesheet XML document XSL Processor java org. apache. xalan. xslt. Process -IN my. Xml. File. xml -XSL my. Xsl. File. xsl -OUT my. Output. File. html Directly applying the Xalan XSL processor Result is either an XML, HTML or text document

Letting a Browser Perform the Transformation Pink Floyd 10. 90 … A link to the stylesheet

The Root of the XSL Document (program) • The Root of the XSL document should be one of the following lines: • The namespace allows the XSL processor to distinguish between XSL tags and tags of the result document

How Does XSLT Work? • An XSL stylesheet is a collection of templates that are applied to source nodes (i. e. , nodes of the given XML document). • Each template has a match attribute that specifies to which source nodes the template can be applied. • The current source node is processed by applying a template that matches this node. • Processing always starts at the root (/).

. . . Template content." src="https://present5.com/presentation/102009364_72145941/image-11.jpg" alt="Templates • A template has the form: . . . Template content." /> Templates • A template has the form: . . . Template content. . . • The content of a template consists of: – XML elements and text (HTML, etc) that are copied to the result, – XSL elements that are actually instructions. • The pattern syntax is a subset of Xpath.

Single Template XSL program Hello World

Hello World Applying a browser to catalog. xml (catalog. xml has a link to catalog. xsl)

Focus on Generating HTML XSL (presentation) XML (content) XSL Processor HTML

Transformation Language • XSL is a transformation language it transforms a document written in one language (XML) into a document of another language (e. g. , HTML). XSL XML Transformation Engine (XSL Parser) HTML

Recall XML • Recall that an XML document is composed of ‘elements’. • For a Book. Catalogue XML document we have the following elements: Book. Catalogue (the ‘root’ element), Book, Title, Author, Date, ISBN, and Publisher.

XSL - all about (Template) “Rules” • Let the XSL processor know when it encounters the root element (e. g. , Book. Catalogue) do [action 1]. • Let the XSL processor know when it encounters the Book element do [action 2]. • Let the XSL processor know when it encounters the Title element do [action 3]. • And so forth…

XSL - all about (Template) “Rules” • Each template rule has two parts: – A pattern or matching part, that identifies the XML node in the source document to which the action part is to be applied: • Matching information is contained in an attribute. – An action or formatting, styling and processing part that details the transformation and styling of the resulting node

XSL Document Structure xsl: stylesheet template rule for the document (template rule for a child element)* action on the child element action on the document

XSL Document Structure [action] [action] [action] . . .

Things to Note • XSL documents are full-fledged XML documents: – As a consequence, if in [action] you want to, say, output an HTML paragraph break you must have both

and

Template Rules Template rules take the following general form: [ action ] Spring 2010 mark. baker@computer. org

Template Rules (Example) The XSL processor, as it parses through the XML document and gets to a element use this template rule. ” “Go to each of my children and apply the template rules to them. ” Spring 2010 mark. baker@computer. org

XSL Processor • A free, open source, Java XSL processor Apache - Xalan - http: //xml. apache. org/xalan-j/ XSL XML XSL Processor HTML Invoking from the command line: java org. apache. xalan. xslt. Process -IN my. Xml. File. xml -XSL my. Xsl. File. xsl -OUT my. Output. File. html Spring 2010 mark. baker@computer. org

Example - Create XSL for Book. Catalogue. xml Paul Mc. Cartney July, 1998 94303 -12021 -43892 Mc. Millin Publishing Richard Bach 1977 0 -440 -34319 -4 Dell Publishing Co. J. Krishnamurti 1954 0 -06 -064831 -7 Harper & Row

First Example • This example will show the XSL Processor parses an XML document and uses the template rules defined in the XSL document to do something for each thing that is found in the XML document.

Terminology In Book. Catalogue. xml we have (snippet): Paul Mc. Cartney July, 1998 94303 -12021 -43892 Mc. Millin Publishing . . . • “Book is a child element of the Book. Catalogue element. • Title, Author, Date, ISBN, and Publisher are children elements of the Book element. ”

Creating a Stylesheet - Step 1 • Draw a tree diagram of your XML document. Document / Document. Type Element Book. Catalogue Element Book. . . Element Book Element Title Text My Life. . . Element Author Element Date Text Paul Mc. Cartney Text July, 1998 Element ISBN Text 9430312021 -43892 Element Book. . . Element Publisher Text Mc. Millin Publishing

Creating a Stylesheet - Step 2 • Create a template rule for every type of node in your tree: – Except for the DOCTYPE node: • The current specification does not allow you to have a template rule for the DOCTYPE node. – e. g. , create one template rule for all the nodes, not one template rule for each of the nodes.

" src="https://present5.com/presentation/102009364_72145941/image-30.jpg" alt=" " />

“The XSL processor returns the value of the thing" src="https://present5.com/presentation/102009364_72145941/image-31.jpg" alt="Explanation “The XSL processor returns the value of the thing" /> Explanation “The XSL processor returns the value of the thing that is selected here” In this example the “thing” that is selected is a text node, so the “thing” that is returned is the value of the text node, i. e. , the text. Spring 2010 mark. baker@computer. org

Creating a Stylesheet - Step 3 • For those nodes in the tree that we want to immediately return (i. e. , not process any of its children): – remove – remove the template rules for the child nodes - these template rules will never be used, so why have them? • For our example, we want the XSL processor to traverse the entire XML document tree so we do not do this step. Spring 2010 mark. baker@computer. org

Put an wrapper around the content added these

Creating a Stylesheet - Step 5 • Tell the XSL Processor that when it encounters a element to output: – “I am at a Book element. Processing its children now. ” – Do this for each element. • Before running your XSL document through the XSL Processor, check it for well-formedness.

" src="https://present5.com/presentation/102009364_72145941/image-35.jpg" alt=" " /> I am at Book. Catalogue. Processing its children now.
I am at Book. Processing its children now.
I am at Title. Here's the title:

I am at Author. Here's the author's name:

I am at Date. Here's the date:

I am at ISBN. Here's the ISBN:

I am at Publisher. Here's the publisher:

Book. Catalogue 1 b. xsl

Default Template Rules • Every XSL document has two default template rules. • These rules are applied when the XSL Processor cannot find a template rule to use from what was written. • Here are the two default template rules: “Match on the document or any element. Return the result of applying the template rules to my children. ” “Match on a text node. Return the value of the text node, i. e. , the text. ”

Multiple Applicable Rules • Suppose that the XSL Processor is processing Book. Catalogue and it gets to the element. • Why does it use • and not the default template rule after all, both apply! • Answer: given two rules that apply, the more specific rule wins: – “*” is much more general than “Book”. – “*” matches on any element. – “Book” just matches on the Book element.

Example 2 • The XSL Processor, when it encounters a book element output: – ‘

Here is a book:
’ and then the data in its children elements. • This is what we want XSLProcessor to send to Book. Catalogue. html. Here is a book: all the data from the first book Here is a book: all the data from the second book Here is a book: all of the data from the third book

Book. Catalogue 2. xsl

Here is a book:

Put the Data into an HTML Table

Single Rule Applied to Multiple Elements • Notice in the last example that a single rule is applied to multiple elements: – • The xsl: apply-templates element (without an attribute) tells the XSL Processor to apply the template rules to all children • The xsl: apply-templates element can have an attribute that tells the XSL Processor to process only the child element that matches “pattern”: – This apply-templates rule allows us to specify the order in which the children are processed.

Specify the order of the table contents

[action] This says that for every Book element, do [action]

For each Book do. . .

Patterns • So far we have seen very simple patterns - simply match against an element name. • XSL provides a rich pattern matching capability. match document match by name match several names “When you start processing the document do. . . ” “When you get to a Book element do. . . ” “When you get to either a Title element or an Author element do. . . ”

Patterns match with immediate ancestor match with an ancestor “When you get to a Title element that has a Book element as a parent do. . . ” “When you get to a Title element that has a Book. Catalogue as an ancestor do. . . ” wildcard match “When you get to any element that is an immediate child of Book do. . ” match by id “When you get to an element that has an id “J. K. ” do. . . ”

Patterns (matching by attribute) “When you get to a para element do. . . ” “When you get to a para element that has an attribute called type do. . . ” “When you get to a para element that has an attribute called type and its value is ‘opening’ do. . . ” “When you get to a para element that has an attribute called type whose value is ‘opening’ and the element has a parent called chapter and it has an attribute called num that has a value ‘ch 1’ do. . .

Patterns (matching by position) “When you get to the first Book element do. . . ” “When you get to the last Book element do. . . ” “Use this rule for all but the last Book element” Other position qualifiers: not(first-of-type()) first-of-any() not(first-of-any()) last-of-any() not(last-of-any()) “The first child element of any type”

Named Attribute Sets • XSL allows you to create a set of attributes and assign a name to it: – What value is this? Reuse! +1 blue Palatino

" src="https://present5.com/presentation/102009364_72145941/image-50.jpg" alt=" " /> +1 blue Palatino Define the named attribute set Use the named attribute set

Numbering • XSL has the capability to number your elements: . This will print out a number followed by a period followed by the results of processing the Title element. The number starts at one and increments each time this template rule is instantiated.

Creating a Numbered Title List

Sorting • Sorting is achieved by adding xsl: sort elements as children of xsl: apply-templates or xsl: for-each. • The first xsl: sort child specifies the primary sort key, the second xsl: sort specifies the secondary sort key, and so on. .

TO Title -

A Common Mistake • Scenario: suppose that the element Book has an id attribute. • We would like to create a hyperlink using the value of the id attribute as the value of the hyperlink’s href. Wrong ”> Correct Attributes values cannot contain “<” or “>”