Your job in this project is to design and implement a mobile "calendar
secretary" using the Aglets Workbench, a mobile agent programming
system based on Java.
Using the Aglets Workbench
The Aglets Workbench is installed in the course directories, at:
Several papers and book chapters on the Aglets framework can be found
through the course papers page. The API documentation is
also available locally.
On CS machines, the directory
contains a single directory tiny, which in turn contains java
sources implementing a very simple mobile agent that
moves between hosts, performing a simple interaction with the user at
each one. (The same files can be found in the project handouts directory via the web.)
Let's say PROJECTPATH is the name of the directory where your
project is going to live. Make sure that a directory named
PROJECTPATH exists, and then do:
cp -r /u/pierce/pub/629/handouts/project5 PROJECTPATH/project5
Next, we need to set some environment variables. If you are a
bash user, the appropriate incantation is
where PROJECTPATH on the fourth line is replaced by your
actual project path. You'll want to add this to your .bashrc
file. (Users of other shells will need to make appropriate
adjustments to this bit.)
Choose two port numbers, PORT1 and PORT2. (Try to choose them
randomly - any numbers over 8000 - to avoid conflicts with other teams
working on the same machine.)
Edit the file Tiny.java and change the lines
private String host = "shovelnose.cs.indiana.edu";
private int lPort = 4434;
private int rPort = 4435;
to reflect the name of your machine and the two ports you've chosen.
You should now be able to recompile the sample aglet program. Go to
the directory PROJECTPATH/project5/tiny and do
to generate class files for the demo aglet.
Next, build an aglet server ("context") listening at the first port
number that you chose:
agletsd -port PORT1 &
You'll be prompted for some registration information; after filling in
the form, create another context at the second port:
agletsd -port PORT2 &
Now create an aglet. Click on the Create button in either context
dialog box. Type tiny.Tiny in the top line of the "create
Aglet" dialog box that appears, and click the Create button at the
You should see the aglet appear in the viewer's status
window, and, shortly afterwards, a dialog box should pop up. Clicking
in the Go button will send the Tiny aglet to the other context, where
it will again pop up a dialog. (If the two contexts were running on
different machines, each pop-up dialog would appear on the local
To get started writing your own code, make a copy of the directory
tiny (as a sibling of tiny within the
PROJECTPATH/project5 directory). Change the package name in
Tiny.java to the name of this directory.
The specifications below are intentionally left fairly vague, to give
you scope for choosing your own design. In fact, feel free to ignore
them entirely and design your own project using aglets to implement a
Feel free to make simplifying assumptions to make your user-interface
design more straightforward. For example, you might want to assume
that there are only four possible time slots for the event being
scheduled and label them 1-4, instead of dealing with days, dates,
24-hour clocks, etc. The purpose of the project is to explore
mobility, not user interfaces.
- Implement a simple calendar secretary agent. It is
started by a user that wants to schedule a meeting with a given set of
other users. She creates the agent, gives it a list of addresses
where the other users can be found, and writes a short text explaining
what the meeting is for.
The aglet visits the given machines, popping up a dialog on each one
and requesting that the user there mark the times at which he could be
free for the meeting. When he's finished, he presses a button that
sends the agent off to find the next user - or, if he was the last
one, back to the original user to report its results.
- Refine the calendar agent so that, if a given user is not at his
terminal when the agent arrives, it goes off looking for someone else
instead of getting stuck there waiting.
- The design so far has assumed that each user is located at a
known machine. Extend it so that users may move around between
machines, signalling their arrival by informing a local agent.
[How robust is your design in the face of machine or communication
- Additional extensions, making interesting use of the facilities
of the Aglets system and/or illustrating the power of the mobile agent
For this part, you can choose between two approaches:
- Small project 5 / large project 6. Design and implement
one or two modest improvements to the design sketched above. Save the
rest of your energy for working hard on project 6.
- Large project 5 / small project 6. Expend some serious
effort and creativity on designing a useful application using mobile
agents. Do something more modest for project 6.
- As usual, please prepare a single directory containing:
- a design document explaining
- what you've done
- why that was a good thing to do
- what you learned from doing it
- working source code
- a demonstration and instructions for how to run it
- Please make sure that your project is self-contained and easy to
navigate. (It would be good to provide an HTML cover page with
instructions for the demo.)
Same as usual.
The project is due at the beginning of class on
Monday, November 17th.
(If you decide to make this your
"major project" and do a smaller project 6, we can negotiate a later
B629: Languages for Programming the Web