Full HTML for

Basic foilset The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc.

Given by Geoffrey C. Fox at Tango Seminar to DoD Modernization MSRC on April 6 1999. Foils prepared April 4 1999
Outside Index Summary of Material

We describe some concepts that will underlie the development of emerging distributed object based systems
What is the Web Document Object Model and why is Dynamic HTML (DHTML) intriguing and XML critical
Why is JavaScript non trivial as the language to capture changes in document object structure and to choose appropriate rendering
  • We stress constraints of cross disability interfaces
Where do CORBA and Jini fit in?
We define the Pragmatic Object Web as the emerging synthesis of multiple object models
We describe the importance of the Web as a source of information objects and as a mechanism for invoking general server side objects
We stress the important role of both Asynchronous and Synchronous collaboration and the web and web-based collaboration allows one to implement it.
We use ASC Gateway project as an example of hybrid object systems

Table of Contents for full HTML of The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc.

 Denote Foils where Image Critical
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1 NPAC Dynamic HTML Examples The Document Object Model Universal Access Other Objects CORBA XML Jini JavaScript etc.
2 Abstract of An Introduction to the Document Object Model and Related Issues
3 Some Relevant HTML XML JavaScript DOM References
4 Topics Covered in Lecture
5 Simplistic Object Web View
6 Other Useful Objects
7 Basic Multi Tier Object architecture
8 Topics Covered in Lecture
9 HTML 4.0
10 Logical versus Visual Design
11 What is XML?
12 XML Compared with HTML and SGML
13 XML Language Elements
14 Example XML as a Serialized Database
15 MathML Example
16 Topics Covered in Lecture
17 Why would you use JavaScript I?
18 Why would you use JavaScript II?
19 Why would you use JavaScript III?
20 Why would you use JavaScript IV?
21 ECMAScript
22 JavaScript Performance Issues
23 Topics Covered in Lecture
24 NPAC Dynamic HTML Examples What is DHTML?
25 Features of DHTML
26 Architecture of DHTML + XML
27 Components of DHTML
28 Cascading Style Sheets
29 Cascading Style Sheets CSS1 (and CSS2) Features
30 A Larger CSS Example illustrating different ways one can specify CSS Info
31 Topics Covered in Lecture
32 Document Object Model
33 Hierarchical Object Components in a Web Page
34 Netscape Version 4 Browser Document Object Tag Hierarchy
35 Use of Position Attributes in JavaScript
36 NPAC Dynamic HTML Examples DHTML 1) Define Layers -- I
37 NPAC Dynamic HTML Examples DHTML 1) Define Layers -- II
38 NPAC Dynamic HTML Examples Define a Layer in a Document using <div></div>
39 NPAC Dynamic HTML Examples Set Positions of a Layer in DHTML
40 NPAC Dynamic HTML Examples Capturing Events in Today's DHTML
41 NPAC Dynamic HTML Examples A User Event Handler in DHTML
42 XML and Document Object Model
43 W3C Document Object Model Level 1
44 Topics Covered in Lecture
45 An Overview of Jini
46 Jini Service Architecture I
47 Jini Service Architecture II: Join
48 Jini Service Architecture III: Lookup
49 Jini Service Architecture IV: Invocation
50 Features of Jini of Relevance
51 Topics Covered in Lecture
52 XML used as a Template
53 Architecture of WebWisdomDB
54 XML Templates -- Example I
55 XML Templates -- Example II
56 Topics Covered in Lecture
57 Front End to LMS 3 Tier Land Management System
58 WebFlow + High Performance Backend 3 Tier Functional Architecture
59 CORBA security is built into ORB
60 Security Model in CORBA
61 CORBA ORB Using Akenti
62 Summary of NPAC's JWORB natural Building Block of the POW
63 DoD Modernization Gateway Project
64 Gateway Schematic
65 Gateway Client
66 Topics Covered in Lecture
67 Architecture of Tango Distance Education
68 How are Objects Used Collaboratively?
69 What is Universal Acccess / Cross Disability Rendering?
70 Naïve Shared Object Strategy
71 If you believe these assertions
72 What Objects should we look at first and what services do we need?
73 What's wrong with Java Clients?
74 What about databases and Lotus Notes
75 What is Involved in Sharing Web Pages?
76 JavaScript Shared Browser with Dynamic HTML
77 Shared Form Illustrated by Shared Access to NCSA Biology Workbench showing how general server objects can be shared from web interface

Outside Index Summary of Material

HTML version of Basic Foils prepared April 4 1999

Foil 1 The Document Object Model Universal Access Other Objects CORBA XML Jini JavaScript etc.

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
Online Seminar April 6, 1999
http://www.npac.syr.edu/users/gcf/msrcobjectsapril99
http://www.w3.org/
Geoffrey Fox
Syracuse University
NPAC
111 College Place Syracuse NY 13244 4100
3154432163
HTML version of Basic Foils prepared April 4 1999

Foil 2 Abstract of An Introduction to the Document Object Model and Related Issues

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
We describe some concepts that will underlie the development of emerging distributed object based systems
What is the Web Document Object Model and why is Dynamic HTML (DHTML) intriguing and XML critical
Why is JavaScript non trivial as the language to capture changes in document object structure and to choose appropriate rendering
  • We stress constraints of cross disability interfaces
Where do CORBA and Jini fit in?
We define the Pragmatic Object Web as the emerging synthesis of multiple object models
We describe the importance of the Web as a source of information objects and as a mechanism for invoking general server side objects
We stress the important role of both Asynchronous and Synchronous collaboration and the web and web-based collaboration allows one to implement it.
We use ASC Gateway project as an example of hybrid object systems
HTML version of Basic Foils prepared April 4 1999

Foil 3 Some Relevant HTML XML JavaScript DOM References

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
http://www.w3.org/ W3C Consortium for HTML XHTML CSS XML ....
Dynamic HTML, The Definitive Reference by Danny Goodman (1st ed, O'Reilly, 1998).
NPAC's Web Resources page, http://www.npac.syr.edu/projects/tutorials/ HREF="http://www.npac.syr.edu/projects/tutorials/HTML/">
JavaScript, The Definitive Guide by David Flanagan (3rd ed, O'Reilly, 1998); The JavaScript Bible by Danny Goodman (3rd ed, IDG, 1998); or download the JavaScript manual from
http://developer.netscape.com/tech/javascript/index.html
HTML version of Basic Foils prepared April 4 1999

Foil 4 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 5 Simplistic Object Web View

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
The Object Web Signifies the merger of distributed object and web technologies
The Pragmatic Object Web asks us to take the best of CORBA (Industry Standard) COM (Microsoft PC Standard) Java (Web Software Infrastructure) and W3C (XML)
An "object" is an entity that can be
  • registered, addressed, located
  • has properties and methods
The most common object is a Web Page
The richest available object model is the Web Document Object Model or DOM
JavaScript is one language to manipulate this DOM
Web Browsers render this object
Web Servers broker this object
As Web Pages are natural user interface to ALL objects, XML extensions to web pages reflects all objects ....
HTML version of Basic Foils prepared April 4 1999

Foil 6 Other Useful Objects

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Contents of (relational) Databases -- give these a web interface and view as an XML (or HTML) stream
  • Web-linked databases use Java Software and W3C serialization (XML) and rendering technology (HTML)
Computer Programs -- from CGI Scripts to Servlets to CORBA IDL brokered Fortran Programs
(Large) data resources -- from file systems to archival storage
Devices -- from toasters, microsensors to surveillance cameras, PC's, Printers, Supercomputers, Telescopes
Electronic Mail Messages -- favorite form of collaboration
People
HTML version of Basic Foils prepared April 4 1999

Foil 7 Basic Multi Tier Object architecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Define Objects and properties / methods (backend) and define services (frontend)
Objects (at "backend") can be on client of course
Broker or Server
Rendering Engine
XML
Result
XML Query
User dependent Style Sheets and Rendering engines
Rendering Engine
XML result
HTML
Objects
Universal Interfaces
IDL or Templates
HTML version of Basic Foils prepared April 4 1999

Foil 8 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 9 HTML 4.0

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
HTML defines the display or rendering of documents
HTML 3.2 (Jan 97) introduced tables, applets, and other capabilities (approx. 70 tags)
The final spec for HTML 4.0 was released by W3C in December 1997
There are three flavors:
  • HTML 4.0 Strict -- Full use of Style Sheets
  • HTML 4.0 Transitional -- Adapt existing world
  • HTML 4.0 Frameset -- If need multiframe window
HTML 4.0 has 93 elements (10 deprecated) and 187 attributes (49 deprecated)
HTML represents an object model for document display
HTML does NOT define an object model for document content -- XML does this
HTML version of Basic Foils prepared April 4 1999

Foil 10 Logical versus Visual Design

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
The logical design of a document (content) should be separate from its visual design (presentation)
Separation of logical and visual design
  • promotes sound typography
  • encourages better writing and is more flexible
HTML mixes the logical with the visual
Internal Representation of Microsoft Word/PowerPoint will/should be XML while "Save As HTML" should gives its visual rendering in HTML
  • XML structure of Word/PowerPoint can immediately be stored in a relational database
  • Dynamic HTML allows rendering of all features of these products whereas current export of Office products uses static images which are both unnecessarily large and incomplete representation
HTML version of Basic Foils prepared April 4 1999

Foil 11 What is XML?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
XML = eXtensible Markup Language
XML is a subset of SGML -- Standard Generalized Markup Language, but unlike the latter, XML is specifically designed for the web
XML is used to define logical document structure
XML is not backward compatible with HTML, but the two coexist quite elegantly
XML can be thought of as an ASCII version of a database
XML can be used as an object IDL to access databases or any objects and so give web HTML templates to access web-linked databases / backend services
XML can be used as inter object data (serialization) format for any object model
XHTML is HTML4 written in XML syntax
HTML version of Basic Foils prepared April 4 1999

Foil 12 XML Compared with HTML and SGML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
XML is a compromise between the non-extensible, limited capabilities of HTML and the full power and complexity of SGML
XML Tags are converted to HTML for display (or other XML tags) by one or more Servers or clients
HTML < XML < SGML
(CSS) (XSL) (DSSSL)
XML is a kind of SGML Lite!
Original
XML
New XML
and perhaps some HTML
Newer XML
and perhaps more HTML
Newest XML
and perhaps all HTML
H T M L
HTML version of Basic Foils prepared April 4 1999

Foil 13 XML Language Elements

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Document Type Definition (DTD), which defines the tags and their relationships
Extensible Style Language (XSL) style sheets, which specify the presentation of the document
Extensible Link Language (XLL), which defines link-handling details
It supports scripting languages such as ECMAScript (JavaScript) or Java
For example a link can be defined in XML as <LINK> <TITLE>XML Recommendation</TITLE> <URL> http://www.w3.org/TR/REC-xml </URL> <DESCRIPTION> The official XML spec from W3C </DESCRIPTION> </LINK>
HTML version of Basic Foils prepared April 4 1999

Foil 14 Example XML as a Serialized Database

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
<?xml version="1.0"?>
<!DOCTYPE BIB SYSTEM "bib.dtd">
<references>
<book>
  • <label>Knuth_1999</label>
  • <title>The Art of Computer Programming</title>
  • <author>Donald E. Knuth</author>
  • <publisher>Acme Inc.</publisher>
</book>
<journal>
  • <label>Bunny_2035</label>
  • <articletitle>Carrot Effect</articletitle>
  • <author>Bugs Bunny</author>
  • <journalname>Journal of Cartoon Psychology</journalname>
  • <volumeᡚ</volume> <numberɳ</number>
  • <page> <fromᡛ</from> <toᡥ</to> </page>
  • <year򗷓</year> <publisher>Acme Inc.</publisher>
</journal>
</references>
XML as serialized version of a bibliographic database
HTML version of Basic Foils prepared April 4 1999

Foil 15 MathML Example

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Notation: is represented as:
<mrow>
<mrow>
  • <msup> <mi>x</mi> <mnɮ</mn> </msup>
  • <mo>+</mo>
<mrow>
  • <mnɰ</mn> <mo>⁢</mo> <mi>x</mi>
</mrow>
  • <mo>+</mo> <mnɰ</mn>
</mrow>
  • <mo>=</mo>
  • <mnɬ</mn>
</mrow>
MathML can be found at W3C WebSite
HTML version of Basic Foils prepared April 4 1999

Foil 16 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 17 Why would you use JavaScript I?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
JavaScript (originally called LiveScript) is a web scripting language for clients and servers
Originally JavaScript was designed to do what you think Java should do -- elegant dynamic animation on the client side
Then along came Java and JavaScript was eclipsed as it was just Netscape and not so well designed
Netscape tried to make it a server side language (LiveWire) instead of Perl but Java was much better here as well
JavaScript lived on for simple arithmetic on client side to produce somewhat better frames (as clicking on a link can call a JavaScript function instead of just loading a URL) and to quickly check forms client side without going back to server which is slow
A serious weakness was that dynamic aspects of JavaScript could only be used at "load" time and other changes of JavaScript required a "reload" which is real ugly and slow
HTML version of Basic Foils prepared April 4 1999

Foil 18 Why would you use JavaScript II?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Then along came Microsoft and Netscape became distracted and quality of Java on the client side suffered and in fact is still problematical as Java in the browser has poor performance and lags Sun's version
Further the Web Consortium W3C never really liked Java butting in and thought HTML was the answer
JavaScript is Java with HTML and browser as AWT
W3C came along with XML and the DOM (Document Object Model)
In particular dynamic HTML extensions allowed one to get many benefits of JavaScript dynamically without reloading ....
Now all this was screwed up in version 4 browsers -- especially by Netscape -- and so the vision was obscured!
At least Microsoft's version 5 browser implements vision well
HTML version of Basic Foils prepared April 4 1999

Foil 19 Why would you use JavaScript III?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
So Java is a good low level tool and how you program your stock market simulation downloaded from the online broker
However dynamical HTML and JavaScript is becoming preferred method of client implementations
Use JavaScript to manipulate "components of documents" and Java to do arithmetic
  • e.g. suppose you want to make your site accessible to blind. Then JavaScript identifies document components and hands text nuggets to Java voice synthesizer and image to fancy captioning system
As world develops HTML + JavaScript will become XML and HTML -- both with JavaScript to capture dynamic issues
On Server, Java always wins (unless you use C++ for performance)
HTML version of Basic Foils prepared April 4 1999

Foil 20 Why would you use JavaScript IV?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Typically JavaScript is invoked from HTML and HTML text and JavaScript text are intertwined
If you need to make a dynamic page from C++ Perl or Java you must write the HTML from these languages
You can invoke applets from HTML but HTML and applet actions are not linked. In case of JavaScript HTML and JavaScript are closely linked
JavaScript is an example of an important concept -- the domain specific interpreter which we can expect to be of growing importance
  • Note Postscript is an interpreter for text layout; MATLAB an interpreter for Matrix arithmetic, Mathematica or Maple for Mathematics .....
Text ...................................................... Computer Language HTML---> JavaScript Java <----- C++
HTML version of Basic Foils prepared April 4 1999

Foil 21 ECMAScript

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
ECMAScript refers to standard ECMA-262 released in June 1997
ECMAScript is essentially JavaScript with all client and server-side features removed i.e. It is the language and not the browser AWT handler
The emerging HTML and XML Document Object Models (DOMs) are bound initially to ECMAScript
So one can use ECMAScript in several different domains (HTML XML VRML ...) by adding support for appropriate domain specific objects
Netscape Site has ECMAScript standard document
HTML version of Basic Foils prepared April 4 1999

Foil 22 JavaScript Performance Issues

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Typically, up to 106 C instructions may be executed in a few milliseconds (the time it takes a person to notice anything!) as one instruction in 1 clock cycle (say 108/sec)
A Java interpreter is roughly 50 times slower than C
Java "Just-In-Time" compiler is roughly 2–8 times slower than C whereas a native Java Compiler (and perhaps future JIT's) are about same speed as C
Perl is 500 times slower than C (an interpreter but analyses whole code before interpreting)
  • Runtime (e.g. I/O) can be as fast as C as it is C!
Tcl, JavaScript (true interpreters) are up to 5000 times slower than C
  • BUT If Java Script in browser invokes optimized C++ internal function, it can easily outperform Java
  • Just as Java itself can of course invoke through JNI C++ code.
  • Need C++ library to be built in as do not want to download
HTML version of Basic Foils prepared April 4 1999

Foil 23 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 24 What is DHTML?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
DHTML = Dynamic HTML
Capabilities of DHTML:
  • dynamic styles -- change the appearance (that is, presentation) of content on-the-fly
  • dynamic content -- change the content itself on-the-fly
  • dynamic positioning -- position page elements (such as images or text) on-the-fly
HTML version of Basic Foils prepared April 4 1999

Foil 25 Features of DHTML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
It is available now albeit in different versions for different browsers
It is an extension of HTML and therefore familiar
It addresses many of HTML's shortcomings
It is focussed at "visual display" of a document and so is orthogonal to XML
We can expect DHTML to change significantly in both implementation and syntax
  • in particular there will be an XML syntax version of VRML and HTML (XHTML draft February 24, 99 at http://www.w3.org/MarkUp/ )
  • The new version of DHTML will be built around a "document object model"
HTML version of Basic Foils prepared April 4 1999

Foil 26 Architecture of DHTML + XML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
3 Scenarios
HTML4
HTML4
User Interacts
with HTML Changing Dynamically Client Side (JavaScript catches mouse
and keyboard
events and
interprets as
changed DOM components:
Browser
renders)
XML
HTML4
Server with XML Parser
XML
Some XML and some
HTML4
HTML4 or XML+HTML4 Browser
HTML version of Basic Foils prepared April 4 1999

Foil 27 Components of DHTML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
DHTML consists of the following:
  • 1) HTML 4.0
  • 2) Cascading Style Sheets (CSS) to attach dynamic properties to document components
  • 3) Document Object Model (DOM) describing and identifying components of a document
  • 4) Scripts (in JavaScript) able to change properties of document components and so implement dynamic structure
HTML version of Basic Foils prepared April 4 1999

Foil 28 Cascading Style Sheets

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
http://www.w3.org/Style/CSS/ is general link
Cascading Style Sheets (CSS1) allow more precise and consistent layout than previous HTML attributes such as <FONT>
Style sheets permit pages to inherit properties from other pages--in effect, they permit object-oriented document structure
CSS2 was released in May 98, and includes support for media-specific style sheets (e.g. printers and aural devices), downloadable fonts, element positioning and tables.
HTML version of Basic Foils prepared April 4 1999

Foil 29 Cascading Style Sheets CSS1 (and CSS2) Features

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
CSS1 allows one to specify layout styles (size, color, position) and associate in flexible way with tags
Flexible placement of style information -- either in sheets (i.e. separate pages), attributes (style="..") or style statements in header of HTML page
Independence from specific scripting languages but natural link to JavaScript and works with XML and HTML
Cascading style sheets i.e. one can have a hierarchy of style definitions from general to organization specific to user specific
Example: A simple style sheet (in file "myStyle.css"): P.special { color: red; border: solid black; }
Now put a <LINK> tag in the <HEAD> to be able to access information: <LINK href="myStyle.css" rel="stylesheet" type="text/css">
In the <BODY> tag, type: <P class="special">A special paragraph!
HTML version of Basic Foils prepared April 4 1999

Foil 30 A Larger CSS Example illustrating different ways one can specify CSS Info

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
<HTML> <HEAD> <TITLE>title</TITLE>
<LINK REL=STYLESHEET TYPE="text/css" HREF="http://style.com/cool.css" TITLE="Cool">
<STYLE TYPE="text/css">
@import url(http://style.com/basic.css);
H1 { color: blue }
H2.vivid {color:pink}
#myid {position:absolute; color:red; top:20; left:50; background-color:red; visibility:hidden}
</STYLE></HEAD><BODY>
<H1>Headline is blue</H1>
<P STYLE="color: green">While the paragraph is green.
<h2 class=vivid>And the secondary heading is Vivid</h2>
<div id=myid>
<h2>Default Color Positionable element</h2>
</div>
</BODY> </HTML>
Selector
Declaration
HTML version of Basic Foils prepared April 4 1999

Foil 31 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 32 Document Object Model

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
W3C DOM (http://www.w3.org/DOM/ ) defines a platform-independent programmatic interface to web documents:
  • provides access to structured data
  • adds object orientation to page layout and design (HTML elements are objects with properties and methods)
  • is implemented with a scripting language
  • defines event model (not in level 1 DOM)
  • defines a way of navigating through component objects in a web page
Initially, DOM is bound to ECMAScript but is language neutral in design
Current Browsers implicitly define a DOM which is somewhat different between Microsoft and Netscape and very different between versions 4 and 5
HTML version of Basic Foils prepared April 4 1999

Foil 33 Hierarchical Object Components in a Web Page

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Here is an example of a particular source document encoded in HTML:
<HTML>
<TITLE>My home page</TITLE>
<BODY>
<H1>My home page</H1>
<P>Welcome to my home page! Let me tell you about my favorite composers:
<UL>
<LI> Elvis Costello
<LI> Johannes Brahms
<LI> Georges Brassens
</UL>
</BODY>
</HTML>
Component Objects in Web Page
HTML version of Basic Foils prepared April 4 1999

Foil 34 Netscape Version 4 Browser Document Object Tag Hierarchy

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
HTML version of Basic Foils prepared April 4 1999

Foil 35 Use of Position Attributes in JavaScript

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Making dynamic pages with HTML and JavaScript requires two types of capabilities.
  • Identifying events of interest (the user interactions that will trigger dynamic structure) and processing
  • Dividing page up into identifiable components where we can separately:
    • move around in x,y position
    • move up and down a stack of pages (decide what's on top)
    • change content and style of components
These capabilities EXIST in current browsers but are incomplete and different
More powerful "standards" are part of W3C DOM1 and DOM2 and presumably these will be adopted
In the meantime we adopt strategy which is supported by current browsers and can evolve to W3C DOM1,2
HTML version of Basic Foils prepared April 4 1999

Foil 36 DHTML 1) Define Layers -- I

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
The first step is to define different named entities in document.
  • The picture shows 6 entities labeled 0 1 2 3 4 5
  • 0 is main window
  • Others subsidiary windows 1-ɱ
  • 4 is layered above 3 and 5
  • There could be other hidden named entities -- either because they had CSS-P visibility attribute set to hidden or because they were completely underneath other named windows
  • Entities could either be scattered around -- seemingly at random or aligned precisely w.r.t. other positionable parts of document
HTML version of Basic Foils prepared April 4 1999

Foil 37 DHTML 1) Define Layers -- II

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
The position CSSP attribute takes values static (default) relative (position relative to where it "should be" in current "context") and absolute (position in current "context")
These are properties of essentially ALL document components in the "DOM of our dreams" (this is what W3C defines)
  • However in today's pragmatic world, one can only use for some HTML tags
  • <DIV> and <SPAN> (<<---- USE THESE!) are supported today by Microsoft and Netscape and are part of HTML4
  • <LAYER> is best "name" (so lets call them layers)and fully supported by Netscape; it is not part of HTML4 and not officially supported by Microsoft
  • <IFRAME> (internal frame) is not in Netscape4 but is in HTML4 and supported by Microsoft
HTML version of Basic Foils prepared April 4 1999

Foil 38 Define a Layer in a Document using <div></div>

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
<style type="text/css" >
#WWmessage1 {position:absolute; color:black; visibility:visible; left:200; top:450; }
</style>
</head>
<body onload="WW_pageisloaded();" >
<h1>This is Page for CPS616 DHTML</h1>
.... See page addon for full material (a form to specify layer properties) .....
<div id="WWmessage1" >
This is a Moving Block of Text<br>
Input (left,top etc.) and see!
</div>
Style
Good Practice for all processing which requires that page elements be fully defined
}
A movable layer
HTML version of Basic Foils prepared April 4 1999

Foil 39 Set Positions of a Layer in DHTML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
function WW_getlayer(idstring) { // Find layer with given label
if( WW_Netscape4 ) {
return eval("document." + idstring); }
else { // Microsoft
return eval("document.all." + idstring); }
} // End WW_getlayer()
function WW_layershiftto(obj,x,y) { // Move layer to given position
if(WW_Netscape4 ) {
obj.moveTo(x,y); }
else { // Microsoft
obj.style.pixelLeft = x;
obj.style.pixelTop = y; }
} // End WW_layershiftto(obj,x,y)
WW_messageobject = WW_getlayer('WWmessage1');
WW_layershiftto(WW_messageobject,parseInt(x),parseInt(y));
id attribute in <div> #WWmessage1 in STYLE
Returned by WW_getlayer
Read in from form as text
Decide on Browser
HTML version of Basic Foils prepared April 4 1999

Foil 40 Capturing Events in Today's DHTML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
function WW_pageisloaded() { // Initialize when page loaded
if(WW_oldbrowser)
return;
if( WW_Netscape4 ) { // Netscape
window.captureEvents(Event.CLICK);
window.onclick=WW_processclick; }
else { // Microsoft
document.onclick=WW_processclick; }
WW_pointerlayer = WW_getlayer('WWpointerblock'); // Pointer
WW_pointerlayer.onmouseover = WW_overpointerblock; // Mouse Over
WW_pointerlayer.onmouseout = WW_offpointerblock; // Mouse Out
WW_pointermessageobject = WW_getlayer('WWpointermessage');
if(!WW_Netscape4 ) { // Microsoft set layer width
WW_pointermessageobject.style.width =200;
WW_pointerlayer.style.width=64; }
return;
} // End WW_pageisloaded()
Capture ALL Click events and set handler
Set event handlers for mouse events recognized
in conventional way
HTML version of Basic Foils prepared April 4 1999

Foil 41 A User Event Handler in DHTML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index NPAC Dynamic HTML Examples
function WW_processclick(e) { // Process Mouse Click
var clickX = WW_eventx(e); // Extract Mouse Click Position
var clickY = WW_eventy(e);
// Position Top right of pointer at mouse click
var width = WW_getlayerwidth(WW_pointerlayer);
WW_layershiftto(WW_pointerlayer,clickX-width,clickY);
WW_layershow(WW_pointerlayer); // Make pointer visible
WW_layertotop(WW_pointerlayer); // set zindex=1000
WW_offpointerblock(); // remove stray mouseover messages
window.status = 'click'; // flag action
// true implies that you continue conventional processing i.e.
return true; // that clicks on links are recognized
} // End WW_processclick(e)
HTML version of Basic Foils prepared April 4 1999

Foil 42 XML and Document Object Model

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
<student stdid="A1231999"> <name>Bugs</name> <surname>Bunny</surname>
  • <address> <street>Walnut</street> <city>Carrotville</city>
  • <country>Cartoon Land</country> </address>
  • <phones> <aphoneɭCC-615-AD123</aphone> </phones>
</student>
HTML version of Basic Foils prepared April 4 1999

Foil 43 W3C Document Object Model Level 1

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
HTML version of Basic Foils prepared April 4 1999

Foil 44 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 45 An Overview of Jini

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
http://www.sun.com/jini/ and also see very interesting Ninja project at UC Berkeley http://ninja.cs.berkeley.edu/
Jini is an innovative distributed computing capability that has features that
  • 1) Naturally follow from Java Implementation or
  • 2) Are interesting architectural choices
Jini enables services to be dynamically linked to users of services
  • It is a technology to produce a federation of linked clients and servers
  • It imagines not a giant monolithic system but rather dynamic collections of dynamic collections
  • Both users and services can dynamically join or leave a Jini federate on a time period of seconds (or longer of course).
Services can be printers, home stereo components, computers or pieces of software or ....
All Jini federate members must support the Java VM or be represented by a proxy that does
HTML version of Basic Foils prepared April 4 1999

Foil 46 Jini Service Architecture I

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Jini has a classic 3 tier architecture with client, lookup service (called broker or server in other architectures) and service provider (the backend)
There are four basic operations: Discovery, Join, Lookup, and Service Invocation
Discovery Process: Service Provider broadcasts a request on network that all service providers identify themselves
Lookup
Service
HTML version of Basic Foils prepared April 4 1999

Foil 47 Jini Service Architecture II: Join

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
If device is not Java enabled, then a proxy can locate the lookup service on the device's behalf
Finding one or more lookup services, the Service Provider loads its Java Interface and array of descriptive attributes into the Lookup Service
Service Provider leases space in yellow pages of Lookup Service for a given time (Say one minute). Lease must be renewed before end of lease time else Lookup Services assumes service has been discontinued -- implements dynamic fault tolerant services
Add
HTML version of Basic Foils prepared April 4 1999

Foil 48 Jini Service Architecture III: Lookup

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Any client locates a Jini Lookup Service and hands a Service Template
  • Template is Java Service Interface (e.g. generic printer interface) as IDL plus a template array of attributes (e.g. resolution and speed of printer)
Lookup Service provides a list of all Services matching this request and Client chooses appropriate service.
Client downloads a Service object which can implement Service
HTML version of Basic Foils prepared April 4 1999

Foil 49 Jini Service Architecture IV: Invocation

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
The downloaded Service Object implements Service
Lookup Service no longer part of transaction
This Service could be:
  • Pure Client Side Software
  • Any combination of Service and Client Side Capabilities
Note Client side Service Object came originally from Service Provider and so automatically consistent and up to date
Service Object can be downloaded from central source by Service Provider to keep itself up to date
HTML version of Basic Foils prepared April 4 1999

Foil 50 Features of Jini of Relevance

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Use of Lookup Service is typical yellow pages service in all distributed systems (cf. DNS etc.)
Use of Java as IDL(Interface Definition Language) and RMI as transport layer is specific to Jini
  • Clearly can be replaced by other object models and in particular XML can be used to specify services
Has a particular query syntax with attribute array and use of simple yes/no matching
  • Could and perhaps should be generalized
  • Concept of "services with precise definitions" and "queries accessing classes of services" seems general
Has a "leasing concept" which seems very valuable in distributed computing where resources are dynamic and fault tolerance important
HTML version of Basic Foils prepared April 4 1999

Foil 51 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 52 XML used as a Template

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Example comes from WebWisdomDB for storing training and education curricula objects -- PowerPoint, HTML, Photos ..
XML embedded as part of HTML "Web Page"
URL of Web Page invokes Servlet
e.g. http://witch.npac.syr.edu/servlet/TDLServlet/witch/index.tdl?USID=67
Servlet leaves HTML untouched but calls Java Methods to process XML tags
This Servlet processes <WW_... tags -- others are left for other servers or browser
HTML version of Basic Foils prepared April 4 1999

Foil 53 Architecture of WebWisdomDB

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Educational Objects i.e.
Data Defining Curricula Material at all levels from "University" to "foil"
Server side
Java(JDBC)
XML Parser
Servlet
Metadata
WebWisdom XML Template Server
Conventional XML/HTML Pages
Dynamically Generated
(IMS/ADL) Metadata
Streaming Audio/Video
Cross Disability Shared Choice of CSS
Templates Defining in XML How educational data stored in Pages
Share with TangoInteractive
JavaScript API
HTML version of Basic Foils prepared April 4 1999

Foil 54 XML Templates -- Example I

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
<!-- WW_CONNECT is a tag that establishes a connection to the database. Connection string may be supplied in the CONNECTION attribute, or if it is omitted (empty string) the default connection string is taken from properties.txt file for current template.-->
<WW_CONNECT CONNECTION=""/>
<html> <head> <title> Separate IMAGE for LOCAL foil
<!-- WW_FOILNUMBER tag takes the position of the current foil in the current presentation. -->
<WW_FOILNUMBER PARENTID="${PID}" FOILID="${FID}"/>
<!-- WW_TITLE is a tag that allows to insert title of a presentation or foil. The presentation/foil is identified by an ID supplied in FOILID attribute. PARENTID is not currently used by the WW_TITLE tag, but can be later used, e.g. to check the formatting properties, which can be defined on the presentation level. FID and PID were supplied by the servlet from query attributes of the URL -->
Yellow is ordinary HTML, Green XML, White Comments
HTML version of Basic Foils prepared April 4 1999

Foil 55 XML Templates -- Example II

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
<WW_TITLE FOILID="${FID}"/>
</title> </head>
<!-- WW_BODYIMAGE inserts a 'body' HTML tag with background image typical for foil files. -->
<WW_BODYIMAGE/>
<tt><a href="#image">Image</a><a href="#buttons"> Buttons</a> </tt> <b>
<WW_LINK FILENAME="temphelp.tdl" ATTR="">HELP!</WW_LINK> * GREY=local</b><tt> LOCAL IMAGE version of Foils prepared
<!-- WW_MODIFICATIONDATE inserts modification date of the current foil -->
<WW_MODIFICATIONDATE FOILID="${FID}"/> </tt>
...... And So On!
HTML version of Basic Foils prepared April 4 1999

Foil 56 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 57 Front End to LMS 3 Tier Land Management System

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Navigate and choose an existing application to solve the problem at hand. Import all necessary data.
Retrieve data
Pre/post-processing
Run simulations
Select host
Select model
Set parameters
Run
HTML version of Basic Foils prepared April 4 1999

Foil 58 WebFlow + High Performance Backend 3 Tier Functional Architecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Globus High Performance Backend
Java Applet Frontend
Java Servers in Middle Tier
Database Service
Computing Service Providers
Visualization
IIOP
/RMI
Invoke Composition Service
HTML version of Basic Foils prepared April 4 1999

Foil 59 CORBA security is built into ORB

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
CORBA has many services defined
Object Management Group has just requested that distributed and parallel computing services be defined
HTML version of Basic Foils prepared April 4 1999

Foil 60 Security Model in CORBA

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
SECIOP
Front End Applet
https
authentication
& authorization
Gatekeeper
delegation
Stakeholders
HPCC resources
GSSAPI
GSSAPI
Layer 1: secure Web
Layer 2: secure CORBA
Layer 3: Secure access to resources
Policies defined by resource owners
https (SSL)
AKENTI
CORBA security service
GSSAPI (Globus)
HTML version of Basic Foils prepared April 4 1999

Foil 61 CORBA ORB Using Akenti

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Mary Thompson, http://www-itg.lbl.gov/security/Akenti/DOE2000/sld014.htm
HTML version of Basic Foils prepared April 4 1999

Foil 62 Summary of NPAC's JWORB natural Building Block of the POW

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
JWORB - Java Web Object Request Broker - multi-protocol middleware network server (HTTP + IIOP + DCE RPC + RMI transport)
Current prototype integrates HTTP and IIOP i.e. acts as Web Server and CORBA Broker
  • HTTP Services built in terms of CORBA services
  • Gives you immediately web interfaces to CORBA
  • CORBA supports applications in any language
  • RMI allows use as Jini Lookup Server
Currently testing support of Microsoft COM
JWORB - our trial implementation of Pragmatic Object Web
First non DMSO implementation of RTI -- HLA (distributed event driven simulation) Runtime at 5% cost(!)
HTML version of Basic Foils prepared April 4 1999

Foil 63 DoD Modernization Gateway Project

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
DoD Modernization Project at ASC Dayton
Client Tier is set of XML Templates and Java front ends
  • Multiple Problem Solving Environments (PSE)
  • Creates User Friendly, "Point & Click" Environment for HPC Resources with seamless interface to any backend
  • Offers Batch Submission, Data Visualization, Problem Solving Strategies
  • Accommodates Multidisciplinary Computational Solutions
Middle Tier is Object Broker
  • Utilizes Commodity Hardware and Software (XML and Corba Web Objects)
  • Implements Security
Back-end Tier using Globus Toolkit and classic HPCC
  • Computing Resources: Supercomputers, Metacomputing, Workstation Clusters
  • Databases
  • Mass Storage Systems
HTML version of Basic Foils prepared April 4 1999

Foil 64 Gateway Schematic

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
HTML version of Basic Foils prepared April 4 1999

Foil 65 Gateway Client

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
XML Templates that you can customize for each domain -- Chemistry is first example
Some "general XML Buttons such as <visualize render="AVS">See it!</visualize> invokes middle-ware visualization service and AVS renderer
Others such <gaussian version="1.37"> <basisfunction> ... are domain specific
Ken Flurchick, http://www.osc.edu/~kenf/Gateway
HTML version of Basic Foils prepared April 4 1999

Foil 66 Topics Covered in Lecture

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web Page objects
General Objects
Pragmatic Object Web
Multi Tier Object/Service Arch.
HTML
XML and XHTML
XML as a Database Serialization
JavaScript/ECMAScript
Dynamic HTML DHTML
CSS Cascading Style Sheets
Document Object Model DOM
Current DOM: JavaScript plus DHTML
W3C DOM
Jini and Service Architecture
XML as Web Template Language
CORBA and HPCC Examples
CORBA and Security
JWORB Pragmatic Object Web
Gateway and XML
Tango Architecture
Collaborative or Shared Objects
Universal Access
Web-linked Databases
Lotus Notes
Shared Web Pages are Everything
JavaScript Shared Browser
HTML version of Basic Foils prepared April 4 1999

Foil 67 Architecture of Tango Distance Education

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
NPAC Web Server
JSU Web Server
Java Tango Server
.......
Share URL's
Audio Video
Conferencing Chat Rooms
White Boards etc.
Address at JSU of Curriculum Page
Teacher's View of Curriculum Page
Student's View of Curriculum Page
Participants at JSU
Teacher/Lecturer at NPAC
.......
Java Socket
HTTP
Java Control Clients
HTML version of Basic Foils prepared April 4 1999

Foil 68 How are Objects Used Collaboratively?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Some sort of activity involves interactions between objects and/or objects and individuals (which can be thought of as objects as well if you want)
Interaction can be synchronous as when individuals talk to each other; parallel program components exchange MPI messages
  • Objects or object properties are shared at same time
Or asynchronous when sharing is done at different times
I post a web page and you look at it later is basic asynchronous sharing model while writing on a blackboard is hallowed synchronous model in teaching
  • other areas are similar
HTML version of Basic Foils prepared April 4 1999

Foil 69 What is Universal Acccess / Cross Disability Rendering?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
This implies choosing a rendering method that best suits client user and respects
  • Any hardware constraints -- network bandwidth or screen resolution or client performance
  • Any sensory or physical limitations of user
e.g. Visually impaired would prefer audio rich rendering
e.g. Muscularly limited users would need appropriate interfaces
New Cascading Style Sheets can express this but need intelligent renderer to make correct decision and allow user to adjust choices
Further one needs decision at the stage of XML input and not after it has already been rendered into HTML
  • HTML expresses "meaning of document" by positioning and other means which are in general impossible to recognize and render in a cross disability fashion
Assume goal is equal and high quality rendering -- do not downgrade material to support cross disability rendering
HTML version of Basic Foils prepared April 4 1999

Foil 70 Naïve Shared Object Strategy

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Assume teachers, students, engineers, shoppers, salespersons, families teach, learn, collaborate, buy, sell, socialize via electronic versions of traditional human interactions combined with shared objects rendered as web pages
  • Most sharing is asynchronous and one usually wishes to share synchronously same material that one accesses asynchronously
  • objects can be (electronic) text books, aircraft designs and simulations, expensive jewelry or photos of grandchildren .....
  • Best sharing must support cross disability rendering
HTML version of Basic Foils prepared April 4 1999

Foil 71 If you believe these assertions

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
One needs to be able to
  • Share specification of object
  • Deliver XML specification of shared object to participants
  • Customize User profile
  • Render from profile to provide cross disability access
  • Provide digital versions of audio video conferencing, pointers, white boards etc.
  • Reliably deliver shared object with appropriate performance (Caching, proxy servers ...)
  • Monitor all of the above
HTML version of Basic Foils prepared April 4 1999

Foil 72 What Objects should we look at first and what services do we need?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
So web documents are the natural choice but actually this doesn't say so much as they can have
  • Java Applets
  • Active X controls
  • General helper applications
And "everything" exports itself to the web including Microsoft Word and Macromedia authoring systems
  • Actually Microsoft Word is rumored to be moving to XML internal form and "Save as HTML" is a reasonable representation of most Word documents
So we will consider first Web documents constructed according to W3C DOM
HTML version of Basic Foils prepared April 4 1999

Foil 73 What's wrong with Java Clients?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Well there is the battles between Sun Netscape and Microsoft which makes Java on the client less robust than Java on the server
However Java allows to build totally general users interfaces and there appear to be no rules.
Thus it does not seem practical to build cross disability interfaces for arbitrary Java applet interfaces
On the other JavaScript and dynamic HTML can do many things that you might have thought one needed Java for
General Java visual interfaces need languages such as UML to describe interface object model?
HTML version of Basic Foils prepared April 4 1999

Foil 74 What about databases and Lotus Notes

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Web-linked databases look "just" like web pages and in fact using XML templates one can store DOM components in database and improve representation of object structure of pages
  • Each bullet of this slide is a separate record etc.
  • XML is natural serialization of a database and correspondingly databases, not web servers are natural place to store XML documents
On the other hand, current Lotus Notes supports a web client but does not naturally integrate with other web resources
  • It provides its own isolated world which is not so satisfactory
  • Instead one should use technologies that add value to a dominant world wide web.
HTML version of Basic Foils prepared April 4 1999

Foil 75 What is Involved in Sharing Web Pages?

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
One needs to certainly share the basic page URL but also
  • Entries into forms specifying object to be accessed -- note sharing client side information implies sharing server side objects
  • Scrolled position on page
  • Dynamic HTML including CSS style parameters such as position
  • Mouse and Keyboard actions observed as events
  • selected (highlighted) content
  • internal JavaScript (but this is consequent to external actions i.e. to observed events)
JavaScript in principle allows one to identify relevant DOM components , change the rendering through choice of style attached to each component and so deliver a cross disability shared rendering
HTML version of Basic Foils prepared April 4 1999

Foil 76 JavaScript Shared Browser with Dynamic HTML

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Shared Pointer added to Internet Assistant PowerPoint on the Web
Movement tracked and shared with JavaScript
Illustrates sharing of W3C Object Model internal to documents
DHTML "Heartbeat" recording shared events in last 60 seconds on application specific "bar" which is locked above all windows -- addresses window clutter
HTML version of Basic Foils prepared April 4 1999

Foil 77 Shared Form Illustrated by Shared Access to NCSA Biology Workbench showing how general server objects can be shared from web interface

From The Document Object Model - Universal Access - Other Objects - CORBA XML Jini JavaScript etc. Tango Seminar to DoD Modernization MSRC -- April 6 1999. *
Full HTML Index
Shared Multiple List
Shared Buttons
Shared Text field
Shared Checkbox
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