Q: What is the Java Shared Data Toolkit?
The Java Shared Data Toolkit (JSDT) implements a
multipoint data delivery service for use in support of
highly interactive, collaborative, multimedia
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
provided, which can be used to ensure mutually exclusive
access to a resource, to perform distributed,
multi-application, atomic signalling, etc.
Q: Why is the version number for the Java Shared Data Toolkit 2.0?
The Java Shared Data Toolkit was originally made available as a
technology release (JSDT 1.0) through the early access pages of Sun's Java
Developer Connection. There were three updates (JSDT
1.1 through to JSDT 1.3). These releases helped us determine the
direction future development on the toolkit should take.
Java Shared Data Toolkit 1.4 was the first commercially available version of
this technology.
We then made the Java Shared Data Toolkit freely available with the 1.5
release.
We then continued to make the Java Shared Data Toolkit freely available with
the 2.0 release.
This new release is 2.0 (rather than 1.5.1 or 1.6), because some method
signature changes were required that broke backward compatibility with
JSDT 1.5.
Q: How do I provide feedback and bug reports on the Java Shared Data Toolkit?
E-mail the information to jsdt-comments@sun.com.
Before you send us a bug report or feature request,
please check the JSDT known bugs/issues to see if this
bug/issue is already known.
If you think you have something new, please e-mail us
with the following information:
- Short description of the problem.
- Configuration information.
Please include the hardware platform, Operating System and version (e.g. Intel P160MMX, 32 MB RAM, MS-Windows NT 3.51).
- Steps to reproduce the problem.
- Text of any error message(s) that appeared.
- Simple test program[s] that reproduce the problem.
If possible, include simple test programs that can be used to replicate the problem. This can make resolution of bugs a much easier task.
If we need any additional information we will contact you.
Q: Why can't I get the Java Shared Data Toolkit examples working with LRMP?
The LRMP version of the Java Shared Data Toolkit requires you to have
downloaded LRMP from:
http://webcanal.inria.fr/lrmp/index.html
and to have added the LRMP jar file to your CLASSPATH.
Make sure that you are starting the LRMP version of the
JSDT Registry. This is started with:
java com.sun.media.jsdt.lrmp.Registry -port
4561
You also need to make sure you are using multicast
addresses with the -server command line option when
starting the examples. For example, the whiteboard
server application should be started with something
like:
java examples.whiteboard.WhiteBoardServer
-server 224.1.2.3 -port 4466 -type lrmp
and the whiteboard user application should be started
with:
java examples.whiteboard.WhiteBoardUser -width
-height 350 -server 224.1.2.3 -port 4466 -type
lrmp
Q: Are there any debugging facilities in the Java Shared Data Toolkit?
The JSDT package and each of the implementations have
been adjusted to use two static boolean variables:
"showMessage" and "showStack". If an exception occurs,
and "showMessage" is set to true, then an exception
message will be printed to stdout. If "showStack" is set
to true, then a stack trace will be printed to stderr.
By default, both of these booleans will be set to false.
To set them to true, add the following lines at the
beginning of your JSDT app:
com.sun.media.jsdt.impl.JSDTObject.showMessage
= true;
com.sun.media.jsdt.impl.JSDTObject.showStack =
true;
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