Transcript Creating Dynamic Thin-Client User

Creating Dynamic Thin-Client
User-Interfaces with Flash and
Java
Brad Neuberg,
[email protected]
The Problem & Motivation
The Problem: Find a new rendering engine for Java.
Motivation: Java is a fabulous networking language
and “model” language, but is a lousy “display”
language.
Problems with Java’s Current
Rendering Engine (JRE 1.2.2)

Large (many megabytes)
 Slow
 Not truly cross-platform (disparate support
across platforms)
 No installed base (Sun has been terrible
with bundling deals
Requirements for a New
Rendering Engine
1)
2)
3)
4)
5)
6)
7)
Must be cross-platform
Must be very fast
Must be small
Can be integrated well with Java
Supports the “new way” of creating UIs
Creates good looking, dynamic UIs
Easy to work with
The “New Way” to Create
User-Interfaces

First appeared with HTML, similar to
Model-View-Controller
 User-interface is completely “unhooked”
from behavior of program
 Designer draws and creates user-interface
using some tools (Dreamweaver, Director,
etc.)
 Program “hooks onto” UI to control it
The “New Way” to Create
User-Interfaces (Continued)

Example: JSP file has UI which “calls”
JavaBeans for behavior.
Advantages of this New Model

Can offer great productivity
 Creates much better-looking UIs
 Offers greater flexibility to evolve UIs
 No throwaway prototype UI
Candidates for the New
Rendering Engine

DHTML + JavaScript
– DHTML totally incompatible across browsers
– Even IE for Mac and IE for Windows have
different programming models
– Slow
– JavaScript is terrible for large-scale engineering
– JavaScript also has few good built-in libraries
Candidates for the New
Rendering Engine (Continued)

DHTML + Java through IBM’s DirectDom
(formally Weblets) Toolkit
– Allows Java to control browser HTML
elements
– Promising, but still at alpha-level
– Large download (~1.5 megs)
Candidates for the New
Rendering Engine (Continued)

Servlet/JSP generated HTML
– No downloads
– Slow trips back to server
– Limited user-interface ability
Candidates for the New
Rendering Engine (Continued)

Mozilla
– XUL (eXtensible UI Language) allows for UIs that are
–
–
–
–
–
controlled by Java
Very cross-platform (available for Linux, Windows,
Mac, Solaris, HP-UX, BeOS, etc.)
Still unstable and alpha-level
Large Download (~2 - ~15 megs, depending on number
of components)
Sluggish
Promising, but not mature yet
Candidates for the New
Rendering Engine (Continued)

SVG (Scalable Vector Graphics) through Adobe’s
Plugin controlled by DirectDom
–
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–
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Wonderful, easy programming model
SVG is a standard
Standard is still immature, though
Viewers are slow
Large download – SVG plugin (~3 megs) + DirectDom
(~1.5 megs)
– Both SVG plugin & Direct Dom are alpha-level
– No tool support to create SVG files
Candidates for the New
Rendering Engine (Continued)

JRE 1.3
– Much faster than previous JREs, but still not
–
–
–
–
fast enough
Swing is now truly mature with JRE 1.3
Large download (~5 megs)
Still beta
Major memory requirements for Swing apps
Candidates for the New
Rendering Engine (Continued)

Flash 4 Plugin + Java 1.1 Native Browser VM
– Flash plugin very ubiquitous (on about ~85% of
browsers)
– Flash plugin is extremely small download (~150K)
– Flash is extremely cross-platform (Flash 4 plugin
available for Windows 95/98/NT, Mac, Solaris, Linux,
and Irix)
– Flash is very fast
Candidates for the New
Rendering Engine (Continued)

Flash 4 Plugin + Java 1.1 Native Browser VM
(Continued)
– Flash has advanced rendering engine (anti-aliased text,
cross-platform fonts, alpha-channel/transparency, textfields, sprites, tweening, etc.)
– Flash has very small compressed files
– Easy to create using Macromedia Flash Authoring
application
– Flash is well-known to designers
What is Flash?

Binary vector based format that supports
animation, interactivity, and text-rendering
 Created with an authoring tool named Flash
 Vector format offers small, fast downloads,
screen-size independence, easy conversion
to print-format, and animation
Flash Examples

Eye4U (shows speed)
 Balthaser (shows text-effects and UI
widgets)
 Yugop Scrolling UI (shows UI widgets)
 FlashZone Action Demo (shows UI
widgets)
 Romeo Design (shows multimedia)
Flash (advanced rendering)
+
Java (advanced networking
and programming)
=
Killer cross-platform
solution
Flash/Java Integration
1.
2.
3.
Allow Java to call methods on Flash
Plugin (Done)
Allow Flash to call Java methods and
create new Java instances (80% Done)
Build on (1) to give the illusion that
objects in Flash are actually Java objects
(TBD)
Allow Java to Call Methods on
Flash Plugin

The Flash Plugin exposes several methods
to JavaScript
– Play()
– GetVariable(varName)
– GotoFrame(frameNumber)
– Etc.
Allow Java to Call Methods on
Flash Plugin (Continued)

Made JavaScript and Java wrapper around
plugin, using LiveConnect
 LiveConnect allows JavaScript to call Java,
and vice-versa
 Most people assume it’s only supported in
Netscape, but it is also completely
compatible with IE
Allow Java to Call Methods on
Flash Plugin (Continued)

Example use of FlashPlugin class:
import org.twoofdiscs.flash.FlashPlugin;
import org.twoofdiscs.flash.MainController;
public class AddressBook {
public void displayAddressBook() {
// get FlashPlugin
FlashPlugin plugin = MainController.getFlashPlugin();
plugin.TCallLabel("/", "DISPLAY_ADDRESSBOOK");
}
}
Allow Flash to call Java
methods and create new Java
instances

Flash has a light-weight scripting language
called ActionScript
 ActionScript has a command call
FSCommand(String command, String
arguments)
 This command can be used to call external
JavaScript functions
Allow Flash to call Java
methods and Create New
Java Instances (Continued)

Created reflective Java and JavaScript glue
to let Flash FSCommands call Java methods
and create Java objects
Allow Flash to Call Java
Methods and Create New
Java Instances (Continued)

Creating Java Object from Flash:
– FSCommand(‘org.twoofdiscs.demo.AddressBook
myAddressBook = new
org.twoofdiscs.demo.AddressBook(“Brad Neuberg”)’)

org.twoofdiscs.demo.AddressBook myAddressBook = new
org.twoofdiscs.demo.AddressBook(“Brad Neuberg”)-
object to create
Java
Allow Flash to Call Java
Methods and Create New
Java Instances (Continued)

Calling Java Methods from Flash
– FSCommand(‘myAddressBook.getContacts()’,
‘/someTarget:var1, true, /, RETURN_RESULT_READY’
– Stop

FSCommand(‘myAddressBook.getContacts()’ – Gives instance
name of previously created Java object and method to run

/someTarget:var1, true, /, RETURN_RESULT_READY
-
Specifies name of Flash variable to put results into, whether the results
are an array, and the movie target and label to restart at
Give the Illusion that Objects
in Flash are Actually Java
Objects

Will allow one to define a Java interface:
public interface BankSummary {
public int getUsersChoice();
public void resetColumns();
}
 Then, a Flash compiler will be run:
– java org.twoofdiscs.flash.callingflash.FlashCompile
BankSummary
Give the Illusion that Objects
in Flash are Actually Java
Objects (Continued)

This will generate a Flash file, that can be
imported into a Flash movie
 This Flash movie will now appear to have
an object named BankSummary that can be
created, cloned, and have methods called on
just like an ordinary Java object.
Give the Illusion that Objects
in Flash are Actually Java
Objects (Continued)

The Java will have no clue that it is talking
to Flash
 Similar to CORBA proxies
The Future

As Java 2D speed increases, the Flash
engine can be written in Java
 An open-source Java Flash engine is
already available
 Everything will be able to remain the same
 Will make it possible to embed Swing
components into the GUI where appropriate