The Shared Data Toolkit for Java Technology (JSDT) implements a multipoint data delivery service for use in support of highly interactive, collaborative applications.

It provides the basic abstraction of a session (i.e., a group of objects associated with some common communications pattern), and supports full-duplex multipoint communication among an arbitrary number of connected application entities -- all over a variety of different types of networks

In addition, this toolkit provides efficient support of multicast message communications. This is accomplished by way of a single send method, and allows the user to define whether or not uniformly sequenced reception of data at all receiving locations is required.

The ability to create shared byte arrays and get and set their values is also provided to session members.

A token-based distributed synchronization mechanism is also provided, which can be used to ensure mutually exclusive access to a resource, to perform distributed, multi-application, atomic signalling, etc.

Two implementations are currently provided:

socket - uses TCP/IP sockets http - uses HTTP protocol.

There is an alias for sending the author/maintainer email related to JSDT. It is:

[email protected]

The JSDT source distribution consists of the following:

AUTHORS - the people who wrote JSDT.
MAINTAINERS - the people who maintain JSDT.
NEWS - the main changes with each new JSDT release.
README.md - the file you are reading now.
ChangeLog - description of changes made to JSDT.
ChangeLog-199<n> - description of changes made to JSDT in previous years.
TODO - the list of known problems, bugs and suggested enhancements.

doc/ - the JSDT documentation.
doc/api - the generated JavaDoc for all the JSDT classes.
doc/userguide - the User Guide in LibreOffice and PDF format.
doc/implguide - the Implementers Guide in LibreOffice and PDF format.

impl/ - various files to help JSDT implementors.
impl/Authentication - describes the various messages passed between a client trying to join a managed session and the server and manager for that session.
impl/Messages - a description of the messages between the proxies and the server.
impl/NOTES - more detailed notes for some of the entries in the TODO file.

out/production/JSDT/ - the JSDT class files and examples.

src - the various JSDT source files.
src/com/sun/media/jsdt/ - the JSDT API classes and interfaces.
src/com/sun/media/jsdt/event - the event/listener JSDT API classes and interfaces.
src/com/sun/media/jsdt/impl - the implementation independent JSDT classes and interfaces.
src/com/sun/media/jsdt/socket - a socket based implementation of JSDT.
src/com/sun/media/jsdt/http - an HTTP implementation of JSDT.
src/com/sun/media/jsdt/template - JSDT template files to use, to start to create a new transpoirt implementation.

src/examples/ - simple examples using JSDT.
src/examples/chat/ - a chat applet.
src/examples/whiteboard - a shared whiteboard applet.
src/examples/ppong - two player networked game based on Atari Pong
src/examples/sound - a audio file server and receiver applet.
src/examples/stock - a stock quote server and viewer.
src/examples/browser - a collaborative web browser and server.
src/examples/phone - an Internet phone and server.
src/examples/synth - a midi keyboard "jam" player and server.
src/images - the various images used by the examples.
src/sounds - the various sounds used by the examples.

src/test/ - a test application that exercises the various JSDT methods.

You will need Java 8 (or later) in order to build JSDT.

The build environment is setup to use IntelliJ IDEA. See their documentation at:

https://www.jetbrains.com/idea/documentation/

In particular the section on working with git repositories:

https://www.jetbrains.com/help/idea/using-git-integration.html

JSDT uses one external module (servlet-api-2.5.jar), which you can download from:

http:https://mirrors.ibiblio.org/pub/mirrors/maven2/javax/servlet/servlet-api/2.5/servlet-api-2.5.jar

this should be placed under the lib directory:

~/IdeaProjects/JSDT/lib/servlet-api-2.5.jar

To build JSDT with the IntelliJ IDEA select Build -> Build Project from the main window menubar.

Each of the examples is setup to recognise certain command line options:

The example servers use the following command line options:

-server <string> - the host name where the server is running.
-port <integer> - the port number the server is using.
-type <string> - the type of JSDT implementation (socket).

The example user applets use the following param attributes:

width <integer> - the width of the example user applet.
height <integer> - the height of the example user applet.
server <string> - the host name where the server is running.
port <integer> - the port number the server is using.
type <string> - the type of JSDT implementation (socket).

The example user applications recognize the following command line options:

-width <integer> - the width of the example user applet.
-height <integer> - the height of the example user applet.
-server <string> - the host name where the server is running.
-port <integer> - the port number the server is using.
-type <string> - the type of JSDT implementation (socket).

The examples are setup to use the socket based implementation of JSDT on the localhost. Should you want something different you will need to adjust the parameters passed to the server and user applications at startup time.

By default, the servers are setup to run on host "localhost" and use various port numbers:

CHAT_SERVER_HOST = localhost
CHAT_SERVER_PORT = 4461

PPONG_SERVER_HOST = localhost
PPONG_SERVER_PORT = 4462

SOUND_SERVER_HOST = localhost
SOUND_SERVER_PORT = 4463

STOCK_SERVER_HOST = localhost
STOCK_SERVER_PORT = 4464

WHITEBOARD_SERVER_HOST = localhost
WHITEBOARD_SERVER_PORT = 4466

TEST_SERVER_HOST = localhost
TEST_SERVER_PORT = 4467
TEST_CLIENT_HOST = localhost
TEST_CLIENT_PORT = 4567

BROWSER_SERVER_HOST = localhost
BROWSER_SERVER_PORT = 4468

PHONE_SERVER_HOST = localhost
PHONE_SERVER_PORT = 4469

SYNTH_SERVER_HOST = localhost
SYNTH_SERVER_PORT = 4470

REGISTRY_PORT = 4561

The first thing you need to do before you run any of the example programs is to launch the JSDT registry of the appropriate type.

This can be achieved by:

• Selecting the src/com.sun.media.jsdt/socket/Registry item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run Registry.main()" from the menu (Ctrl-Shift-F10).

You need to start one copy of the chat server. This is done by:

• Selecting the src/examples/chat/ChatServer item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run ChatServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the chat user applet/application running.

To launch a single instance of the application:

• Select the src/examples/chat/ChatUser.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run ChatUser.main()" from the menu (Ctrl-Shift-F10).

To launch a single instance of the applet:

• Click on the Run -> Run... menu item from the main menubar at the top of the IntelliJ IDEA window and then select the 'ChatUser-Applet' menu item from the popup window that is displayed.

This is a very simple chat program. The applet consists of three parts:

- a means of setting a name for the user.
- a scrolling list of messages.
- a means of sending a new message.

The first thing to do is to set a name for the user. Type the users name in the upper text field, and press Return. The text field is grayed out, and the "SignOff" button is activated.

You have now joined the chat session. You can send messages by typing them in the bottom text field and when you are ready to send them, press Return. The message will be sent to all users joined to the chat session. It will appear as the last entry in the scrolling message list.

See the TODO file in this distribution for the list of currently known bugs and suggested enhancements for this example.

You need to start one copy of the ppong server. This is done by:

• Selecting the src/examples/ppong/PpongServer.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run PpongServer.main()" from the menu (Ctrl-Shift-F10).

You can have two copies of the ppong user applet/application running.

To launch a single instance of the application:

• Select the src/examples/ppong/Ppong.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run Ppong.main()" from the menu (Ctrl-Shift-F10).

To launch a single instance of the applet:

• Click on the Run -> Run... menu item from the main menubar at the top of the IntelliJ IDEA window and then select the 'Ppong-Applet' menu item from the popup window that is displayed.

Ppong is a two player network game, based on the classic Atari Pong game.

Press "Start a Game" to begin. If someone else is already waiting to play, you will start playing with them right away. If there is not a partner waiting for you, go get a pal to fire up this URL or hang out and wait for a partner.

You can also fire up another instance of your browser and play against yourself. Not as easy as you think!

The game plays to 7 or until one of you presses "End Game". The paddle on the left is your paddle. To control your paddle, just move your mouse up and down the screen and it will follow.

You need to start one copy of the whiteboard server. This is done by:

• Selecting the src/examples/whiteboard/WhiteBoardServer.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run WhiteBoardServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the whiteboard user applet/application running.

To launch a single instance of the application:

• Select the src/examples/whiteboard/WhiteBoardUser.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run WhiteBoardUser.main()" from the menu (Ctrl-Shift-F10).

To launch a single instance of the applet:

• Click on the Run -> Run... menu item from the main menubar at the top of the IntelliJ IDEA window and then select the 'WhiteBoard-Applet' menu item from the popup window that is displayed.

This is a simple shared whiteboard program. The applet consists of an upper drawing area and a lower control area.

There are eight different brush sizes in five colors (black, red, blue, green and yellow). There are five different drawing operations:

• clearing the drawing area.
• drawing a dot in the current brush style and color.
• drawing a line in the current brush style and color.
• drawing text.
• drawing a circle in the current brush style and color.

When you do a drawing operation, all whiteboard users will also see the same operation in their drawing areas.

Select a brush by clicking on the appropriate style in the control panel.

Select a color by clicking on the color in the control panel.

To clear the drawing area, select CLR from the control panel.

To draw a dot, select the brush style and color you want. Then select the DOT option in the control panel. Then click at the appropriate point in the drawing area.

To draw a line, select the brush style and color you want. Then select the LINE option in the control panel. Then click twice in the drawing area to define the lines endpoints. A line will be drawn between these two points.

To draw text, select the TEXT in the control point. Then click in the drawing area where you want the text to appear. Then type in the text, hitting the Return key to end it.

To draw a circle, select the brush style and color you want. Then select the CIRCLE option in the control panel. Then click twice in the drawing area to define the center of the circle and the radius. A circle will be drawn using the given center point and radius.

See the TODO file in this distribution for the list of currently known bugs and suggested enhancements for this example.

You need to start one copy of the sound server. This is done by:

• Selecting the src/examples/sound/SoundServer.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run SoundServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the sound user applet/application running.

To launch a single instance of the application:

• Select the src/examples/sound/SoundUser.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run SoundUser.main()" from the menu (Ctrl-Shift-F10).

To launch a single instance of the applet, type:

• Click on the Run -> Run... menu item from the main menubar at the top of the IntelliJ IDEA window and then select the 'Sound-Applet' menu item from the popup window that is displayed.

This is a very simple sound server program and corresponding receiver applet.

When a sound user program (the receiver) starts up, there are four buttons displayed (some of them initially inactive):

- Connect       used to connect to the sound server
- Start         used to start the audio file being sent to this receiver.
- Stop:         used to stop the audio file being sent to this receiver.
- Disconnect    used to disconnect from the sound server.

The sound server is continuously playing the audio file to interested parties. When you connect to the server and press start, you are added to that list and will receive audio packets from the server, which are sent out to the speaker.

Pressing Stop will remove you from this list of interested party, and hence stop you receiving further audio packets.

The sound example uses an unreliable (UDP) channel to send out the audio data.

You need to start one copy of the stock server. This is done by:

• Selecting the src/examples/stock/StockServer.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run StockServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the stock user applet/application running.

To launch a single instance of the application:

• Select the src/examples/stock/StockViewer.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run StockViewer.main()" from the menu (Ctrl-Shift-F10).

To launch a single instance of the applet:

• Click on the "Run 'Stock-Applet'" menu item from the Run menu in the main menubar at the top of the IntelliJ IDEA window.

The stock viewer will display multiple stock quotes simultaneously, which are being sent out by the stock server. The stock server is using the "quote.yahoo.com" web site to get quote information. The stock quotes are being continuously updated. Each quote also displays news quotes associated with that stock symbol, which are being continuously scrolled.

The controls to the left of each stock quote news determine the direction the news scrolls, or whether it's stopped.

Stock symbols can be added with the "Add:" textfield. Stock symbols can be removed with the "Remove:" textfield.

The "Update" button will get the latest stock information, and restart the scrolling of any stock quote news. The "Quit" button terminates the stock viewer.

A stock viewer application can be started with a -stocks command line option with a set of quotes that should be initially displayed (eg: -stocks AAPL+GOOGL+MSFT)

The stock viewer applet has a similar "stocks" parameter.

You need to start one copy of the Teacher (server) application. This is by:

• Selecting the src/examples/browser/Teacher item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run Teacher.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the Student user application running.

To launch a single instance of the user application:

• Select the src/examples/browser/Student item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run Student.main()" from the menu (Ctrl-Shift-F10).

The Teacher uses the browser to drive an HTML based presentation. The Students use the same browser in "slave-mode", to view (and keep in synch with) what the Teacher is showing.

There are four buttons at the top; "Back", "Forward", "Reload" and "Exit" to help control the presentation. You can also type new URL's into the "Location" text field. Currently, only URL's starting with "http:" and "file:" are recognised.

You need to start one copy of the phone server. This is done by:

• Selecting the src/examples/phone/PhoneServer item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run PhoneServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the phone user application running.

To launch a single instance of the application:

• Select the src/examples/phone/PhoneUser.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run PhoneUser.main()" from the menu (Ctrl-Shift-F10).

Note that each instance must be on a different machine. JavaSound can only open the Mixer once per machine.

This example provides an audio phone connection between two or more computers over the network.

When the PhoneUser application starts up, enter your name in the text field at the top and press return. You will be added to the phone conference, and you will see a list of the current callers.

JavaSound will automatically open the input channel (ie. microphone) and output channel (ie. speakers) and you can start your phone call.

You need to start one copy of the MidiServer server. This is done by:

• Selecting the src/examples/synth/MidiServer item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run MidiServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the MidiSynth user application running.

To launch a single instance of the application:

• Select the src/examples/synth/MidiSynth.java item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run MidiSynth.main()" from the menu (Ctrl-Shift-F10).

Note that each instance must be on a different machine. JavaSound can only open the Mixer once per machine.

Each user of the MidiSynth application will automatically be started on a different Midi Channel. This will allow you to "jam" with the other users, selecting different instruments, keyboard notes etc...

You need to start one copy of the test environment server. This is by:

• Selecting the src/test/TestServer item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run TestServer.main()" from the menu (Ctrl-Shift-F10).

You can have multiple copies of the test environment user applications running. To launch a single instance:

• Select the src/test/TestUser item from the Project menu on the left side of the IntelliJ IDEA window.
• Right mouse clicking on this item and select "Run TestUser.main()" from the menu (Ctrl-Shift-F10).

The test environment will perform a variety of method calls that are designed to exercise the majority of the JSDT implementation.

The type of the Session is dynamically loaded depending upon the URL given. The URL definition for JSDT now looks like this:

Session: jsdt:https://<host>:<port>/<type>/Session/<sessionName>
Client: jsdt:https://<host>:<port>/<type>/Client/<clientName>

where <type> currently can be:

socket - TCP socket based.
http - HTTP based.

• Date priorities are ignored (both implementations).

• No unreliable channels (http implementation).

• Cannot handle Data messages greater than 8 Kbytes on unreliable (UDP) Channels (socket implementation).

This toolkit has borrowed text, ideas, and definitions from the ITU T.122 recommendation for Multipoint Communication Service for Audiographics and Audiovisual Conferencing Services Definition.

It's definition has received input from a lot of people to whom I'm very grateful. These include:

Duane Northcutt, Alan Ruberg, Randall Smith, Bo Begole, Craig Struble, Ed Grossman, Trevor Morris, Tom Rodriguez, Brian Knep, Daniel Enting, Christopher Nicholas, John Patterson, Eduardo Pelegri-Llopart, Rolande Kendal, Kevin Solie, Justin Couch, Haam Tham, Jeff Kesselman and various members of the ShowMe team at SMCC.

Suggestions for further improvement would be most welcome, plus bug reports and comments.

Copyright (c) 1996-2005 Sun Microsystems, Inc. All Rights Reserved.