ECT 360
Introduction to the
Class
Prof. Robin Burke
ECT 360
Fall 2004
Outline
Introductions
 Course and Syllabus
 XML
 XHTML
 Homework #1

Introductions

Student information sheet
Administrativa

Contacting me




Questions




CS&T 453
x 25910
rburke@cs.depaul.edu
Try the course discussion forum
Automatically mailed to all students
I will also post announcements here
Course web site

http://josquin.cs.depaul.edu/~rburke/courses/
f04/ect360/
About Me
3rd year at CTI
 PhD in AI, 1993
 Research

AI applications in E-Commerce
 "smart catalogs"

Taught web development since 1996
 What I hope to get out of teaching this
class

Course

Introduction to XML



concentrate on XML's uses for the web
many other uses!
Three parts




XML standard
XML validation
XML transformations
Some DOM programming
Course cont'd
Seven homework assignments
 Midterm project
 Final project
 Allocation

Homework – 40%
 Midterm project – 30%
 Final project – 30%

Midterm project





Instead of a midterm
10/6
Two-person teams
Choose an XML language and report on it
Possibilities


SVG, VoiceML, XSL-FO, MathML, SMIL,
SOAP, WSDL, UDDI, BPEL4WS, XBRL
anything else you think interesting
Midterm project
Proposal
 Due next week 9/15
 Email message with the following

Name / email address for each partner
 1st/2nd/3rd choice for XML application

Grading




Three Components
Knowledge
 Does the work display correct technical knowledge?
Reasoning
 Does the work indicate good problem-solving skills?
Communication
 Written work: Is the answer well-written English?
 Code: Does the answer display good coding /
documentation style
Grading, cont'd

A = Excellent work





B = Very good work





Complete knowledge of the subject matter
No major errors of reasoning in problem solutions
Competent written answers
Readable coding style
C = Average work





Thorough knowledge of the subject matter
Well-considered and creative solutions
Well-written answers
Employment of impeccable coding style
Some gaps in knowledge of subject matter
Some errors or omissions in problem solving
Written answers may contain grammatical and other errors
Coding may be stylistically awkward
D = Below average work




Substantial gaps in knowledge of subject matter.
Problem solving incomplete or incorrect
Poor English in written answers
Ineffective coding style
Resources

Text


Carey, P. New Perspectives on XML
(Comprehensive). Thomson Learning
Tools

XML Spy
• 4.3 included with book

XML Spy Enterprise 2004
• available in 7th floor lab
Discussion enhancement

Card distribution
XML
eXtensible Markup Language
 Misnomer

Not a language
 Technology for creating languages

XML



Looks a little bit like HTML
But with a wide variety of tag names
Reason

HTML and XML have a common ancestor
• SGML


Developed for entry and management of
very large documents
Why do we need XML?
Web publishing with HTML





Develop content
Determine how content should be displayed
on pages
Encode content in HTML
Content available to users
Problem

what happens when content changes
• design decisions must be rethought

what happens when design changes
• HTML must be rewritten

designer and author must work closely
Web publishing with XML
Develop XML application for content
 Develop content
 Content encoded in XML
 Design pages
 Write stylesheet to render pages in
HTML
 Content available to users

Benefits
If design changes, only stylesheet is
affected
 Different pages / displays can be
generated from the same content
 Designer and author need not interact

Big picture

Modularity is a good thing



decoupling of data's structure from its use in
a particular application
lowers effort of repurposing data
Modularity requires standards

non-application specific data representation
• not in the interest of any application vendor

XML is the language in which such
standards can be expressed
XML applications
Purpose-specific languages that
conform to the XML standard
 Many are standardized
 In-house languages easy to develop
 XML is becoming the default choice
for data storage format


MS Office 2003
Example: Syllabus
<syllabus
xmlns="http://josquin.cs.depaul.edu/~rburke/namespaces/sylla
bus">
<course>
<course-number>ECT 360</course-number>
<course-title>Introduction to XML</course-title>
<prereqs>
<note>One quarter of programming</note>
<and>
<or>
<course-number>CSC 211</course-number>
<course-number>CSC 261</course-number>
<equivalent/>
</or>
<course-number>IT 130</course-number>
</and>
</prereqs>
</course>
... see full example ...
Note
Structure determined by needs of
application
 Other design choices could be made

separate components of course
number
 text for prerequisites

Note
Mixed content
 Use of external namespaces
 Entities
 Internal referencing

The rules of XML




Documents consist of elements, attributes and content
 (and a few other things)
Elements are set off by tags in angle brackets
 start tag for element foo <syllabus>
 end tag for element foo </syllabus>
Anything in between the start tag and end tag is
element content
Attributes are additional data associated with an
element
 indicated by name/value pairs inside the start tag
• <hwk ref="hwk2">
More rules


Comments
 enclosed by special character sequence
 <!-- -->
Document prolog
 before the first element
 contains declarations
 typically
• declare that it is xml
• declare the relevant document type

Processing instructions
 information that the XML parser doesn't use
 passed along to the application
 Special tag <?
Entities

Special characters


Certain characters part of the language
Need a way to indicate these
• &lt;  <

Entities can be defined as part of a
document type


useful for inserting standard text
&copyright; might insert a standard copyright
notice
Document tree
Document is just one form of XML
 More useful for computation


Tree representation
XML Tree
syllabus
offering,
etc.
course
coursenumber
coursetitle
prereqs
and
TEXT
"ECT 360"
TEXT
"Introduction
to XML"
note
description
coursenumber
TEXT
"IT 130"
or
TEXT
“One quarter of programming”
coursenumber
coursenumber
TEXT
"CSC 211"
TEXT
"CSC 261"
equivalent
TEXT
"This course
is..."
Tree

Nodes
elements
 text nodes


Attribute lists
Paths
A path traverses the tree
 XPath provide syntax for tree traversal
 Example


/section[2]/meeting[1]/day/
Transformation

XML transformations change the XML
tree
adding
 deleting
 changing contents

Well-formed vs valid


A well-formed document is one that obeys
the syntactic rules

it can be parsed

<foo bar="2"><baz>thud</baz>&zap;</foo>

well-formed document
A valid document has been validated
against some standard



what is the entity zap?
is baz a legal subelement for foo?
unknown without a definition for foo
XML Validation
Validation is the process of checking
an XML document against a standard
 Different languages for defining such
standards

DTD – document type definition
 XML Schema
 RELAX NG
 others

Document type

The document type specifies the legal
structure of the XML document
order, contents of elements
 legal attributes and default values
 etc.


Designing a document type means
deciding what data will be stored and
how
HTML


HTML is not XML-compliant
XML is case-sensitive


XML requires quotes around attributes


HTML optional
XML requires end tags


HTML is not
Optional in some cases for HTML
XML requires /> syntax for empty elements

HTML does not
XHTML



Latest HTML standard
Makes HTML XML-conformant
Different flavors

Transitional
• allows style information as part of the document
(align attribute)

Frameset
• allows frames

Strict
• no frames, no style attributes
• assumes use of a stylesheet for rendering
Benefits of XHTML

XML


decouples data from application
XHTML
decouples content from style
 for web documents

Modularity = More pieces
HTML
document
Web browser
XML
data
XHTML
document
XSLT
stylesheet
CSS
stylesheet
Web browser
More pieces =
More flexibility
XML
data
XSL-FO
stylesheet
PDF
document
XML
data
XSLT
stylesheet
SVG
graphics
Converting to XHTML

No sloppiness




tags must nest
end tags everywhere
quotes on attribute values
remove deprecated elements / attributes
• replace with style

XML-specific

/> for empty elements
• like img

declarations
• xml
• doctype
• namespace

lowercase
Example
HTML  XHTML conversion
 Validation


on-line validator
Assignment #1
Convert a file to XHTML
 Use the online-validator or XML Spy
 Due

before class time next week
 submit to COL
