Assignment 5: Simple Groupware

This is an PAIRS assignment. Due: Monday, April 6.

Objective

In the first three assignments you learned how to put together Swing applications , extend and design your own components, and decouple your interface and model (“back-end”) parts of your application. The energyJournal you built, however, is a single-user application. In this assignment you will be extending it to support some simple multiuser activity, so that >1 user can add view and add notes to your journal entries in real-time.

To do this, you will essentially be building the basics of very common software architecture – a client-server (C/S) system.

The learning goals for this assignment are:

• Experience with simple sockets (networks programming) in Java
• Experience writing a server and client application.
• Experience with using simple server-client structures to manage a joint data object .

Description

Don't be intimidated by the length of the homework description! Although long, most of this writeup is here just to provide detail about what I expect from this assignment, as well as some hints about how best to do the implementation.

In this assignment, you will be adapting your energyJournal to allow 2 users to view and add notes to a journal entry at the same time. This means that you will in effect be supporting two user interface applications (clients) to your application (the server that maintains the model). Because the goal of this assignment is to learn how to manage the simple C/S architecture, I do not expect you to implement the complete functionality of a journal (adding and deleting journal entries and phots), but just to show that you can get manage simple input and output in the form of text and graphic annotations

There are a number of specific requirements for this assignment:

#1: Basic client/server architecture.

In class we discussed a simple example with one server and one client. You will be dividing your application into two running programs : an energyJournal server and an energyJournal client. When you run the system, you will use one server and TWO instances of the client, representing two users. The server will keep track of all notes (strings) on each journalEntry (and all journal entries if multiple. See below). The client will implement the user interface services to manipulate the journal.

The energyJournal should have at least two journal entries in it. The client will have all the same functionality as the previous energyJournal tool, i.e. you can add strings/notes to a journal entry, add photos, etc. However, the server will keep track of what journal entry the client is looking at and any changes to the text notes that the client makes. The following functionality will be implemented:

1. when user 1 is looking at a journal entry, user 2 will be notified which entry she is looking at, and vice versa.

• Hint: you will need a new ui component to show which users are “logged into” or using the system
• Hint: this should be the first handshake you exchange with the system

2. when user 1 adds a note (text string) to a journal entry, user 2 will see that note only when user 2 looks at the respective entry. So if user 2 is looking at the same entry, user 2 will see the notes as they are added.

• Hint: this will mean that you will need to have some form of “submit” or “save” function to send the notes.
• Hint: you will need a way to uniquely identify journal entries; consider title or date.

3. if user 2 is NOT looking at the entry being annotated, and looks at it later, user 2 will see all the new notes.
4. A user can only delete notes that she has added, so each note is associated with one user but visible to both.

• Hint: you will need to add new properties to the note for each journal entry to identify authorship.

5. when a user has added a new annotation to a photo the other user will be notified.

There are several things you have to do in order to decouple your application:

• divide the functionality of your application into server and client. This does NOT mean you need to not use MVC (or Delegate/Model)
• extend your interactive energyJournal tool to be a client that sends and receives notes and notifications to and from a server
• write a simple server to receive notes and view instructions, associate them with a user identity, and deliver notes.
• You will be using the Java networking classes and sockets to implement this system.

The server/client only needs to run in real time: that is, you do not need to save the state of the entries for later. (see below for extra credit)

Extra Credit

There are a lot of ways to augment this assignment, should you choose to. Some obvious ways are:

• Extending the system to allow adding new entries
• A user can add a new entry such that the other user gets it as well
• Saving the state of the collaborative energyJournal so that a user can log in later and get all the entries and notes.

Deliverable

You may do this assignment in a team of TWO. While you can use any development environment you choose, you are not allowed to use "GUI builder" type tools (like JBuilder or Eclipse GUI Builder).

The assignment is due on Friday, April 3 (week 13). YOU MUST DEMONSTRATE THIS TO ALI AND ME either in the workshop on that Friday or before by private arrangement, although you can submit the code on email by midnight that day as usual following the standard instructions below.

To turn in the assignment, please follow the same process as last time: submit the code on email following the standard instructions below.

0. Make sure your program is runnable from the command line using the command "java energyJournalClient” and “java energyJournalServer”.

1. Create a new directory using your last name as the name of the directory.

2. Compile your application and place both the sources and classfiles into this directory (they can be at the top-level or in a subdirectory, whatever you want).

3. Put a README.txt file (described below) into the top level of the directory. This file should contain your name and email address, the version of Java you used (1.5.x or 1.6.x, please) as well as any special info I might need in order to run your code (command line arguments, etc.)

4. ZIP this directory and submit it via email.

5. include, as usual, a Software Design Document that describes the design of your system.

If you do any extra credit work, be sure to let us know about it in the README file so that we don't miss it!!

Please take care to remove any platform dependencies, such as hardcoded Windows path names or dependence on a particular look-and-feel that may not exist on all platforms. Also, if you use any images in your application, please make sure that you include these in your ZIP file and that your code will refer to them and load them properly when from from inside the directory that's created when I unZIP your code.

Grading for this assignment, and future assignments, will roughly follow this breakdown:

• 60% functionality
• 40% good architectural design, coding style, commenting

Please let the TA or me know if you have any questions.