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README.TXT
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Olivetti JavaTalk
=================
1996 07 16
JavaTalkClient v. 1.25
JavaTalkServer v. 1.17
(c) 1996 Olivetti Research Limited
INDEX:
Introduction
Licence and copyright
What do you need?
Connecting as a user
Running a JavaTalk server
Acknowledgements
Packing list
Contact information
Introduction
------------
JavaTalk is a simple but effective multiuser chat program. Someone
somewhere runs the server software and installs a suitable web page,
then everyone else can join the chat by simply going to that page with
their browser. You go to that page and whatever you type appears on
the screen of everybody else who is watching the page at the same
time. As simple as that! No messing around, no software installation,
no client software to run, no command set to learn. If you want to
give it a test drive, come to
http://badges.cam-orl.co.uk/~fms/javatalk
Writing a chat system in Java has been a popular idea with many
developers and if you search the web you'll certainly find many more
implementations. I know of at least four more. So what has JavaTalk
got for you that makes it better than the others? Well -- that's up to
you to decide, but here are three basic reasons to consider.
* SIMPLE. No complicated command set to remember. No operators, chat
rooms, privileges, private whispers or any of that stuff. Just go to
the JavaTalk page and anything you type is seen by everyone else. Zero
training needed.
* SMALL. The classes for the client software total less than 15K. That
means quick loading time, even on slow links.
* FREE. Because I've got a smart boss, both the executable and the
source are available to you for free, no licence form to fill in, no
questions asked. You can use it as you wish on your own web pages, or
as an internal communication facility in your intranet.
Licence and copyright
---------------------
Copyright (c) 1996 Olivetti Research Limited
Permission is hereby granted, without written agreement and
without licence or royalty fees, to use, copy, modify, and
distribute this software and its documentation for any purpose,
provided that the above copyright notice and the following three
paragraphs appear in all copies of this software, its documentation
and any derivative work.
In no event shall Olivetti Research Limited be liable to any party
for direct, indirect, special, incidental, or consequential damages
arising out of the use of this software and its documentation, even
if Olivetti Research Limited has been advised of the possibility of
such damage.
Olivetti Research Limited specifically disclaims any warranties,
including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. The
software provided hereunder is on an "as is" basis, and Olivetti
Research Limited has no obligation to provide maintenance,
support, updates, enhancements, or modifications.
Derived or altered versions must be plainly marked as such, and
must not be misrepresented as being the original software.
What do you need?
-----------------
* To participate as a client:
You need a Java-enabled browser. Then simply connect to a page
that runs a JavaTalk server (like for example the JavaTalk home
page mentioned above) and tell your friends to join you there at
the arranged time.
You don't need to download anything, neither the executable nor
the source release of JavaTalk. Everything you need will be picked
up automatically by your browser as and when you visit the web
page.
* To run your own JavaTalk server:
You need the ability to run a Java interpreter on the same machine
as your web server.
Grab the executable release, unpack it in its own directory, edit
the example web page if you want to, and launch the server.
* To modify the program:
You need a Java compiler and developer's kit. Currently available
for free from Sun, as well as for money from commercial vendors.
Grab the source release.
All of the above, plus info on newer versions if any, can be found on
the JavaTalk home page (see "contact info" at the end of this file).
Connecting as a user
--------------------
Most of what appears in this section should be easy to figure out
without instructions, but I'll spell it out in detail just so that you
have a reference handy.
Go to the page of the JavaTalk server you want to connect to. The fact
of going to the page makes your browser download the applet and
connects you to the JavaTalk server.
When the applet has loaded you'll see two windows: a big one above and
a one-line one below. You type, one line at a time, in the one-line
window, pressing Enter after each line. What you type is sent to the
server which then echoes it back to the upper window of everyone who
is connected.
The echoed lines are prefixed with the name of the sender. You can set
your name to whatever you want by using the command "MYNAME xxx"
(commands are all uppercase so that they are unlikely to clash with
anything you normally type). Replace xxx with your chosen name, of
course. Don't choose a terribly long name or there won't be much room
left for your messages and people will have to scroll horizontally,
which is a nuisance.
Before you use MYNAME for the first time, your default name will be
the internet address and port number of the socket you are using to
connect to the server.
To see who else is connected to the server at the time, type "WHO"
(the second and last command understood by the current version of the
server).
If you don't type anything for a while, the server will suspect that
you went away and will warn you. If you want to stay in, type
something (and press Enter to send it). Otherwise, after another
little while, you'll be disconnected.
(Technical note: this reaping process is performed to get rid of those
zombie users who used to appear as connected even though they had long
since gone away. It turns out that a known bug (SUN bug 1234731, see
http://java.sun.com/java.sun.com/products/JDK/1.0.2/KnownBugs.html) in
the Windows implementation of the Java socket libraries prevented the
JavaTalk server from detecting that they had gone away. So I
pre-empted the problem by kicking out inactive users, regardless of
whether their socket looked OK or not. If you run your own JavaTalk
server, you can customise the timeouts.)
When you are disconnected from the server, either because the server
kicked you out or because the server couldn't be contacted on the
given address and port (maybe because it wasn't running?) then the
applet will not display any windows or buttons: it will just say "Not
connected to server. Threads stopped." To reconnect (assuming the
server is there to connect to), just reload the page.
Every time you leave the page, you disconnect from the server (though
of course you won't see the above message because the applet won't be
visible any more). The other participants to the conference will get
the message "User xxx left the conference". Conversely, every time you
enter the page, you join the conference and again the others are
notified.
There are two checkboxes at the bottom of the applet that activate a
debugging feature to measure the time it takes for your messages to
travel from you to the server and back (the roundtrip delay). This is
done by sending a special extra timestamp line every time you send a
regular line. The server doesn't do anything special-- it just echoes
the timestamp like it does with every other line. Your client, though,
recognises it when it gets it and with some advanced mathematics
(namely a subtraction) it computes how long the message took to get
back. This time is then printed in the prompt that preced