TDNC System Design

The assignment is about developing a set of models for ToDoNotes.com, an internet start-up company that aims to provide a web interface for users to create and manage their to-do notes. The project requires the development of use case diagrams, analysis class diagrams, and sequence diagrams to describe the primary and secondary actors, use cases, classes, attributes, operations, and relationships between them.

Scenario
a) ToDoNotes.com (TDNC) is an Internet start-up company that aims at
“digitalising” the traditional paper-based list on which users are writing
down a list of tasks that they will need to carry out in the near future.
The aim is to provide a web interface where the user can register by
providing his personal details (name, age, address and e-mail) and
select his username and password. The following rules apply:
After logging on to the site, the user is able to create to-do notes
containing the text of the task (s)he wants to perform and a
deadline.
The system will attach a status to each note (new once created,
open until five days before the deadline, deadline approaching
up until three hours before the deadline, critical for the last three
hours and overdue once the deadline has passed).
The notes can be enhanced by the addition of “attachments”, i.e.
other documents with content helpful to the user when carrying
out the tasks specified in the note; examples of such documents
can be Word documents, images and so on.
On top of the free user, the user can register for a “premium”
account: the benefit of such an account is that a user can link to
“shared” notes from other users. This way users can create a
project, each can create a note with their own tasks and share
them together (a project can be created even if notes are not
shared if the user wishes to group a number of their own notes
together).
The users of a premium account will have to pay a fee to be
able to use the additional features TDNC offers them;
At the end of each month, a check is made to see which
premium accounts will have their subscription ending by the end
of the month so that users can be notified – TDNC is planning to
use a commercial mass mailing system so that e-mails can be
tracked;
At the end of the subscription period, if the user does not renew
his premium account, the account does not get deleted but is
degraded to a regular account. When logging in the user should
be warned that certain features have been disabled and that he
should renew his premium subscription if he still wants to use
them;
In this case one can only edit her notes, but the status and text
of the other note will be visible as well.
Finally, in order to make the development of notes faster and easier for endusers
ToDoNotes.com is offering a collection of already created text to be used
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as part of a note; these ready-made sentences are divided into different
categories (e.g. home, work, computing and so on) depending on the text.
Questions
You are expected to develop a set of models on TDNC and answer the following
questions.
Question 1 – Use Case Diagram

a) Develop a use case diagram for TDNC, showing the primary and secondary
actors, the use cases and the relationships between them. Pay attention to all
actors, including the secondary actors.
b) Develop use-case specifications for the use case “Add Note” and any related
use-cases (i.e. such that have <<include>>/<<extend>> or generalisation
relationships with the use case “Add Note”). The specifications should cover
all the options listed in the statement of requirements and should:
spell out the interaction between the actors and the system related to
adding a note,
send a confirmation using an email confirmation with the note details,
cover the important exceptional circumstances (alternative flows) that
might occur.
Make plausible simplifying assumptions if/when needed, but make sure
these are clearly stated in your submission.
Question 2: Analysis class diagram
a) Develop an analysis class diagram for TDNC. Concentrate on the problem
domain classes, showing their attributes and important operations and
the associations between the classes.
There is no need to include type information, get and set methods, or
constructors.
Consider a minimal set of boundary and control classes that might be
needed for use case realization.
Relationships:
o Use associations where appropriate and include in your models
association or role names, direction arrows, and multiplicities,
but don’t worry about navigability.
o Use generalization/aggregation/composition where
appropriate.
o Don't bother with dependency relationships
Substantiate your answer using one or more of the taught techniques for
identifying classes and their relationships: noun/verb analysis procedure, CRC
cards, robustness analysis. You may use more than one technique in order to
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improve your diagram, e.g. by discovering new classes, attributes or
operations, but using more than one analysis method will not necessarily get
you extra marks.
Question 3: Use case realization (sequence diagram)
Draw a sequence diagram that realizes the use case “Add Note”. The diagram should
cover all possible branches, loops and alternatives that are documented in the use
case specifications you develop in your answer to Q1b. Make sure that your sequence
diagram is consistent with the class diagram you develop in your answer to Q2 and
with the use case specifications you develop in your answer to Q1b.

Format ( Use Visual Paradism)
All UML diagrams must be created using a UML tool and exported
as images for
subsequent inclusion in the submission document. Diagrams drawn without a
tool
will be penalized by deducting from the awarded mark.
Your coursework must be submitted as a single PDF file. Export your diagrams from
the UML tool you have used as images, and then assemble all your answers, text and
diagrams, in a single word processor file and convert to PDF. Make sure you diagrams
are legible (size, fonts,…).