Displaying the XML document

1
Displaying the XML document

• Summary of last week
• Coding the stylesheet - .xsl including examples
  of code
• XSL Design issues
• E-Commerce issues
• Summary

2
Summary of last week

• Via XML Spy we used the Microsoft XML parser
  which includes an XSLT processor.
• This is the MSXML 4.0 parser (which is
  pre-installed within IE6.0) but we could have
  used any external XSLT processor for this
  purpose.
• We assigned a XML stylesheet (a .xsl file) to an
  XML document (a .xml file).
• lt?xml-stylesheet type"text/xsl"
  href"PODstyle.xsl"?gt

MIME type
3
Summary of last week

• The XSLT processor analyses the XML document into
  a hierarchical tree structure (starting with the
  root) made up of what are called nodes this
  is called a node tree.
• This node tree is for internal use.

4
Part Picture of a node tree

• Proofofdelivery

root node
element nodes
Deliverydetails
rad100
productid
text node
5
Summary of last week

• Nodes can be
• elements e.g. poddetail
• attributes e.g. price
• text e.g. 50.00
• The XSLT processor will then use the stylesheet
  assigned to the XML document, transforming the
  element that it finds into HTML via your XSL
  templates.
• The XSL stylesheet contains instructions on how
  to use (navigate and display) the nodes.

6
XSL coding

• What follows is a selection of useful things
  which we think you can use for the assignment.
• Exploring everything about XSL/XSLT coding is
  beyond the scope of this module too large!
• For those interested there are a few professional
  books on this subject area in the library.
• Look for books by publishers Wrox Press and
  OReilly.

7
XSL code

• Last week we used the
• xsltemplate match/
• e.g.
• lt?xml version"1.0" encoding"UTF-8"?gt
• ltxslstylesheet version"1.0" xmlnsxsl"http//ww
  w.. "gt
• ltxsltemplate match"/" /gt
• What does this do?

8
XSL code

• ltxslstylesheet version"1.0 xmlnsxsl"http//ww
  w.w3.."gt
• This is assigned to create a default namespace
  elements declared in the .xsl stylesheet
  beginning with the prefix xsl will be recognised
  as belonging to this namespace.
• To recap on namespaces see the www.w3schools site.

9
XSL code

• We need namespaces in the cases where we want to
  build an XML document using element names from
  multiple schemas that might clash with each other
• e.g. a book tag from Amazon might have a
  different structure to one from Waterstones but
  our order XML document offers us the choice of
  supplier so how does the XML document validate
  itself?

10
XSL code

• ltxslvalue-of selectelement/gt
• Example of use
• lttd width"200 bgcolor"aaaaff"gt
• ltbgtCustomer IDlt/bgt
• ltxslvalue-of select"ProofOfDelivery/Customer/Cu
  stomerID"/gt
• lt/tdgt
• What does this do?

Tree location
11
XSL coding useful tips

• static or constant information.
• Remember that the stylesheet can incorporate
  simple text formatting
• e.g. in our example from last week the POD header
  information for the address of Westlake Radiators
  and an associated image.
• This is good when appropriate which is
• do we need to send this data in the .xml file
• or do we just need to display it?

12
XSL code useful tips

• Dealing with iteration how are you going to
  display the lines of the POD?
• Firstly revisit the Schema solution for the
  delivery details.
• The schema should show that the delivery lines
  are unbounded i.e. we can have more than one line
  per POD.
• We need to reflect this in the stylesheet how?
  See next slide

13
For-each

• for-each and value-of tags help us process data
  effectively.
• ltxslfor-each select"ProofOfDelivery/DeliveryDet
  ails"gt
• ltdiv align"center"gtltxslvalue-of
  select"LineNo"/gt
• lt/divgt
• ltxslfor-each /gt

14
XSL code useful tips

• Creating HTML tables.
• Use of the HTML tags for tables.
• lttablegt can have a border and spacing info
  specified
• lttrgt rows can have custom styling (also see ltthgt
  tag)
• lttdgt data cells contain displayable information
• lt/tdgt
• lt/trgt
• lt/tablegt
• Use hex values for colour (named colours work but
  are not part of the web standards.)

15
XSL code useful tips

• Using HTML attributes
• Incorporating gif or jpeg files
• ltdiv align"center"gt ltimg src"title.jpg"
  width"300" height"200" /gtlt/divgt
• Image width and height attributes are in pixels
  (naturally) and notice that the img tag has a /
  at the end of it to comply with the
  well-formedness requirements of XML.

16
E-Commerce issues

• The how of what to display can be understood but
• The what to display is more difficult.
• Who decides what to display?
• Do we replicate the existing documents or use the
  opportunity for change the XSLT Designer tool
  might be of some use in this respect in the
  design of forms.
• There is obviously a business process
  reengineering issue (BPR) with the above the
  paperless dream!
• Interesting XML standard for BPR see www.bpmi.org

17
Summary

• XSL/XSLT is a programming environment which can
  be used for web publishing and as we will see in
  later weeks manipulation and querying.
• Business to Business Commerce is all about
  business forms E-Commerce of course is the
  electronic version (or should be)
• It follows that careful design of the viewable
  form is important.