Click DVDs
“Just click to pick”
___________________________
CS4125 Systems Analysis and Design
Chantelle Geoghegan - 0544981
Danielle Frawley- 0545511
BLANK MARKING SCHEME
CS4125: Systems Analysis
Assignment 1: Semester II, 2008-2009
Name: Chantelle Geoghegan
ID: 0544981
Name: Danielle Frawley
ID: 0545511
Item
Detailed Description
Marks
Marks
Allocated
Awarded
Sub-total
Presentation 

Total
2
General Presentation
Adherence to guidelines i.e. front
cover sheet, blank marking
scheme, table of contents
4
Narrative
Narrative description of business
1
scenario
5
Software
Is it linear (Waterfall) or iterative
Lifecycle
(RUP).
1
Discuss risk management strategy?
6
Project Plan
Plan specifying timeline, deliverables,
1
and roles.
7
System
System architecture diagram
1
Architecture
8
Requiremen

t
9
Analysis
Use case diagram(s) and structured
3
use case descriptions(s)

Non-functional (quality) attributes
1

Screen shots / report formats
1

Method used to identify candidate
1
classes
3

5
Class diagram with generalisation,
composition, multiplicity, dialog,
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control, entity, interface classes, etc.
1.5

0.5
Two communication diagram
8
Page 1

Sequence diagram

State chart with annotated
transition strings

1
1
Entity relationship diagram with
cardinality
10
Design

Description of an architectural or
3
design pattern that was evaluated.
Cannot use MVC, Broker and
1
Singleton.

2
diagram

7
Pattern incorporated into class
Refinement of class diagram from
analysis to include MVC architectural
pattern, and collection classes

1
Refined interaction diagram from
analysis with MVC elements
11
Data
Fragments to illustrate different
dictionary
artifacts created during requirements,
1
analysis and design.
12
References
14
Online
Week 8: Use cases
1
Assessment
Week 10: Class and Communication
1
1
2
Diagrams from analysis phase
TOTAL
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30
Page 2
TABLE OF CONTENTS
Blank marking scheme ........................................................................................................................................1
Narrative Description ..........................................................................................................................................5
Software Lifecycle Model [1] ............................................................................................................................7
Project Plan and Allocation of Roles .......................................................................................................... 10
System Architecture .......................................................................................................................................... 11
Three-Tier Architecture .............................................................................................................................. 13
Discussion of UML Workbench Used .................................................................................................... 14
Requirements ....................................................................................................................................................... 15
Functional .......................................................................................................................................................... 15
Non-Functional ................................................................................................................................................ 25
Use Case Diagrams......................................................................................................................................... 26
GUI Prototypes ................................................................................................................................................ 29
Staff User Interface Prototypes .............................................................................................. 29
Member User Interface Prototypes ...................................................................................... 30
Analysis.................................................................................................................................................................... 33
CandiDate Objects .......................................................................................................................................... 33
Class Diagram................................................................................................................................................... 34
Sequence Diagram ......................................................................................................................................... 34
Communication Diagram ............................................................................................................................ 37
State Chart ......................................................................................................................................................... 38
Entity Relationship Diagram..................................................................................................................... 39
Design ....................................................................................................................................................................... 40
Architectural Style ......................................................................................................................................... 40
Model-View-Controller Pattern .............................................................................................. 40
State Pattern ................................................................................................................................... 41
Proxy Pattern ................................................................................................................................. 41
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Façade Pattern .............................................................................................................. 42
CLASS Diagram including MVC ................................................................................................................ 43
Staff package ..................................................................................................................................................... 44
Member Package ............................................................................................................................................ 45
Cart package ..................................................................................................................................................... 46
Rental Package................................................................................................................................................. 46
Dvd package ...................................................................................................................................................... 47
price package.................................................................................................................................................... 47
Sequence Diagram including MVC ......................................................................................................... 48
Deployment Diagram ................................................................................................................................... 49
Data Dictionary .................................................................................................................................................... 50
References .............................................................................................................................................................. 53
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NARRATIVE DESCRIPTION
“ClickDvds” is a new company that has created an online shop whereby members can
rent DVDs and have them delivered directly to their home. After registering their name
and address, customers can browse through a wide selection of DVD titles and place
them in a virtual shopping trolley. A maximum of three DVDs can be rented at one time
by a single customer. Customers can add and remove DVDs from their shopping trolley
or quit without making a purchase.
Payment is made by submitting credit card details online. DVDs are dispatched on the
day of order and delivery times are usually within 36 hours depending on the
customer’s location. Credit cards are debited on the day of dispatch.
DVDs must be returned and have arrived in the store by the return date specified when
the order was taken. If the DVD has not been returned by this date then an extra charge
will be placed on the customer’s account. The customer can extend the rental period
after the order has been placed by accessing their online account. This will also place an
outstanding charge on the customer’s account if they do not wish to pay on order.
Customers will not be able to rent any more DVDs until this charge has been paid. This
is how the customer interacts with the system. In order to keep the system up to date
there are many sub-systems involved.
DVD Management Systems keeps a record of the DVDs that are available to rent as
well as the DVDs that are currently rented and the date of return. This is the main subsystem used by the system. Through the website it informs the customer of the DVDs
that are available to rent as well as the date when out-of-stock DVDs will be available.
This system is also responsible for adding new DVD titles and removing DVD titles that
are available to rent from the online store. If the DVD has not been returned by the
return date, the system notifies the member management system and updates the
member’s cart information.
Price Management Systems keeps the prices of DVDs. The price of a DVD depends on
the type of DVD rented. For example, New Release movie costs more to rent than a
Children’s movie. The types include: New Release, Classic, Children's. Any outstanding
payment a customer has is due to a late return or extending the rental time. Credit Card
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details are stored electronically for relay to the card processing centre when the DVDs
are dispatched.
Member Management System keeps a record of each member. Only customers that
have an account can access the online system. Each member is represented by a
membership number. This system is responsible for adding and removing a member as
well as updating a member’s details such as the member’s name or address. The
member system communicates with the account system to find out whether the
customer owes any money.
Rental Management System stores the DVDs information. This includes the DVDs
name, type, rental period and price. The type, rental period and price can all be changed.
The type of DVD may change depending on its release date and intended audience. The
rental period is decided by the customer. The price depends on the type and rental
period.
Each Sub-System must communicate with each other in order to maintain the overall
system and keep the information up to date. This results in a well-maintained, easy to
use system.
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SOFTWARE LIFECYCLE MODEL
[1]
For our System Design software lifecycle model we have chosen to use the Traditional
lifecycle, also known as the Waterfall lifecycle Model. The first formal description of the
waterfall model is often cited to be an article published in 1970 by Winston W. Royce
(1929–1995.) It was developed in the late 60’s to try and produce a systematic
approach to engineering. There are 7 individual phases of the Waterfall lifecycle model
which are to be followed sequentially. These phases are: System Engineering,
Requirements analysis, Design, Construction, Testing, Installation and Maintenance. To
follow the waterfall model, one proceeds from one phase to the next in a purely
sequential manner and the model maintains that one should move to a phase only when
a proceeding phase is completed and perfected.
1. System Engineering:
This phase involves firstly identifying the major requirements that the system has The
next step after this is to identify those parts of the system which would be best
implemented in software, hardware and the components which should be allocated to
human participants. In essence this phase of the Waterfall model defines how all the
major parts of the system will interact with each other.
2. Requirements Analysis:
This phase of the model is used for a more intense gathering of the systems
requirements and also for clearly defining each of these requirements. Fact finding
techniques are often used for the gathering of requirements and also to aid their
analysis. During this phase the objective moves to identify what the system users would
require from the software.
3. Design:
When the systems requirements are known, then work can begin on determining how
best to design and construct a system which fulfils these requirements. The design of
the system is first concerned with the specification of the architecture which defines the
software components and their relationships. It involves arriving at a balance between
conflicting requirements within environment constraints. Human activities can also be
included in the design at this phase.
4. Construction:
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This phase involves turning the completed system design into actual program code.
Some of this coding may be automated, and can use different programming languages as
well as different database management systems for different areas of the system.
5. Testing:
There are several levels of testing performed on the system to ensure that it satisfies
user requirements. Components can be tested individually and then as a subsystem.
This is then followed by the testing of the whole system together.
6. Installation:
After a successful testing phase the system can be transported to the customer for an
introduction. The system needs to be introduced carefully to minimize disruption.
There should be a contingency plan in place which is appropriate to the level of use.
7. Maintenance:
As it is likely that the system will be subject to change over its lifetime, corrections to
the software may have to be made at some point. It is also possible that the maintenance
phase will be used for implementing aspects of the systems behavior which may not
have been done before installation. This may have been due to time constraints etc.
Requirements changes may also occur and this will often have to be taken into account
during the maintenance stage.
Supporting Arguments for the Waterfall Model:
Time spent early on in software production can lead to greater economy later on in the
software lifecycle; that is, it has been shown many times that a bug found in the early
stages of the production lifecycle (such as requirements specification or design) is
cheaper, in terms of money, effort and time, to fix than the same bug found later on in
the process.
A further argument for the waterfall model is that it places emphasis on documentation
(such as requirements documents and design documents) as well as source code. In less
designed and documented methodologies, should team members leave, much
knowledge is lost and may be difficult for a project to recover from. Many prefer the
waterfall model for its simple approach and argue that it is more disciplined.
The waterfall model provides a structured approach; the model itself progresses
linearly through easily understandable and explainable phases and thus is easy to
understand. For each design phase in the Waterfall model there are a number of
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explicitly defined deliverables, which many see as a major justification of this model.
These deliverables can be used to monitor productivity and also the quality of activity
performed.
Criticisms of the Waterfall Model:
Many believe that real projects very rarely follow a sequential lifecycle like that of the
Waterfall model. Some project phases overlap and certain things may need to be
repeated. Others believe that it is impossible, for a project, to get one phase of a
software product's lifecycle perfected before moving on to the next phases and learning
from them.
If clients change their requirements after a design is finished, that design must be
modified to accommodate the new requirements, it assumes that designers are able to
foresee problem areas without extensive prototyping and at least some investment into
implementation.
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PROJECT PLAN AND ALLOCATION OF ROLES
Week
Deliverables
Allocated to
07
Narrative Description
Chantelle Geoghegan
07
Software Lifecycle
Danielle Frawley
09
System Architecture Discussion
Danielle Frawley
Requirements
08
Use Case Descriptions
Chantelle Geoghegan & Danielle Frawley
08
Non-Functional Requirements
Chantelle Geoghegan & Danielle Frawley
08
GUI Prototypes
Chantelle Geoghegan & Danielle Frawley
09
Use Case Diagrams
Danielle Frawley
Analysis
08
List Candidate Objects
Chantelle Geoghegan
09
Communication Diagram
Chantelle Geoghegan
09
Sequence Diagram
Danielle Frawley
09
State Chart
Chantelle Geoghegan
09
Entity Relationship Diagram
Chantelle Geoghegan
10
Class Diagram
Chantelle Geoghegan
Design
11
Class Diagram including MVC, State and
Chantelle Geoghegan
Facade Patterns
11
Sequence Diagram incl. MVC
Danielle Frawley
12
Architectural Style Description
Chantelle Geoghegan
12
Data Dictionary
Danielle Frawley
Extras
12
Use Case using OCL
Danielle Frawley
12
Deployment Diagram
Danielle Frawley
12
Data Management incl. Proxy Pattern
Chantelle Geoghegan
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SYSTEM ARCHITECTURE
There are many integrated parts which make up the Click DVD system. Each part has its
own functionality and so the decision was made to separate these parts of the system
into their own distinct packages. In order to group these parts, it was essential to look at
the different responsibilities of each integrated part. The packages were hence grouped
as follows:

Member Management Package
This package includes everything to manage the Members of Click DVD. It
includes a member entity which holds all relevant information for the members
account.

Staff Management Package
This package includes everything needed to manage all the staff who is an
employee of Click DVD. All staff details are held in a staff entity class.

Rental Management Package
The Rental Management Package was created to manage Rentals which can
occur at Click DVD.

DVD Management Package
The DVD Management package was created to manage the DVDs in stock at
ClickDVD. DVD details are stored in a DVD entity.

Price Management Package
The Price Management package includes everything needed to manage the prices
of DVDs. The details for prices are stored in three different subclasses of an
abstract class Price.

Cart Management Package
The Cart Management package is used to manage each member’s cart.
In the analysis phase the approach decided upon to take was to “Program to
interface, not implementation.” This was done because by allowing the system to
depend on interfaces instead of the implementation, there is lower dependency
between classes. It also allows for implementation to vary. Two other benefits which
can be seen from programming to interface not implementation are:

Clients remain unaware of the specific types of objects they use, as long as the
objects adhere to the interface that clients expect.

Clients remain unaware of the classes that implement these objects. Clients only
know about the abstract class or classes defining the interface. [4]
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This concept also allows us to build functional structures but to keep them loose enough
for change and reusability. Concrete classes are instantiated, but by using the abstract
class interface, (instead of the concrete classes’) flexibility is brought to the
implementation.
The package diagram below shows the dependencies between each package in the
system as well as their respective interfaces.
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THREE-TIER ARCHITECTURE
For the purposes of this project the standard 3 tier architecture is used for the Click DVD
store system. The three layers included in the architecture are:



Presentation Layer
Business Layer
Data Layer
The implementation of this 3 tier architecture can be seen in the following diagram:
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DISCUSSION OF UML WORKBENCH USED
For this project, “Select Architect”, from the “Solutions Factory” software package was
used to create the UML diagrams included in the project.
Select Solutions Factory is an integrated set of products and modeling tools for Service
and Component based development, design review, requirements management code
generation and reuse. It tightly couples component based development and solution
assembly. It includes both analysis and design functionality. Select Architect is a feature
of Select Solutions Factory and is what was primarily used for creating the UML
diagrams in this project.
Select Architect is a scalable design environment for pragmatic Business
Motivation Modeling (BMM), Business Processing Modeling (BPM), Service and
Component Based Development and design, UML and database design. Select Architect
is widely recognized and accepted as a consistent innovator in the design tools and
modeling tools market. As it was used in this project for the creation of UML diagrams
such as sequence, communication, entity and class diagrams, it was essential to become
familiar with the features and tools it uses. After these tools were mastered, Select
Architect became an essential tool in the completion of this project.
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REQUIREMENTS
FUNCTIONAL
Use Case
Rent DVD
Goal In Context
Member Requests to Rent a DVD for specified amount of
time for an agreed price.
Scope & Context
Company, Sub-function
Preconditions
The customer is a member
The DVD is available to be rented
The customer has not gone over their limit for Renting
DVDs
Success End Condition
Member has rented the DVD.
There is one less DVD available.
We have received money for the goods.
Failed End Condition
We have not given the member the DVD, the correct DVD,
or the member has not paid for the DVD
Primary, Secondary
Member, Administrator, Credit Card Company
Actors
Trigger
Request for Rental
Description
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Step
Action
1
Member requests to rent DVD
2
Verification that member is in system
3
Check DVD is in stock
4
Check Member hasn’t gone over limit
5
Check for outstanding payments
6
Agree Rental Days
7
Member receives DVD
8
Store receives payment for DVD
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Extensions
Variations
Step
Branching Action
2a
Customer is not member
2ai
Customer is added to system
3a
DVD is not in stock
3ai
Renegotiate Rental
4a
Member has exceeded Rental limit
4ai
Order cancelled
5a
Member exceeds agreed rental time
5ai
Extend Rental Days
Step
Branching Action
1
Member can order over the web
6
Member receives by post
7
Member pays by card
Related Information
Rent DVD
Priority
Top
Performance
5 minutes to order instant payment
Frequency
100 per day
Channels to actors
Interactive, Database
Open Issues
What if credit card is stolen?
What if we only have part of the order?
Due Date
Release 1.0
Super ordinates
Find Member, Find DVD
Subordinates
Add Rental
USE CASE: Become Member
Description
In order to become a member the customer must register their details with the store.
Once registered, the customer will receive a membership number which they will use to
access the store.
Pre-Conditions
Post-Conditions
Actor Actions
System Response
The customer is not
The customer is a
1. The actor selects
2. Register Details
already a member.
member and has
the “Register”
page is displayed.
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received a
button on the home
4. Customer
membership
page.
account is created
number.
3. Required fields
using the received
are filled out and
details. The
the “Register
customer’s
Account” button is
membership
pressed.
number is display
on screen.
Extension
None
USE CASE: Login
Description
The customer must enter their membership number and password to login.
Pre-Conditions
Post-Conditions
Actor Actions
System Response
The customer must
The customer has
1. The actor selects
2. The system
be a member and
logged into the
the “Login” button
displays the login
have a valid
system and can now
from the home
page.
membership
rent DVDs.
page.
4. Login is
3. Actor enters their
confirmed and
membership
redirects the actor
number and
to the home page.
number.
password into the
required fields and
presses the
“Confirm Login”
button.
Alternative Courses
Step 4 Login not valid, displays login not valid message.
USE CASE: View Account
Description
The customer views their account details which display their registered information as
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well as DVDs currently rented and outstanding payments.
Pre-Conditions
Post-Conditions
Actor Actions
The customer must
The customer’s
1. The actor logs in
be a member and
account is displayed
(use case 2)
System Response
have a valid
2. The “View
3. The customer’s
membership
Account” button is
account is
number.
selected.
displayed.
Extension
After step 3 the customer can edit their account details.
USE CASE: View Shopping Cart
Description
The customer can view their shopping cart while browsing for DVDs. The shopping cart
displays all DVD which have been added.
Pre-Conditions
Post-Conditions
Actor Actions
System Response
The customer must
The customer’s
1. The actor logs in
be a member and
shopping is
(use case 2)
have a valid
displayed
2. The “View
3. Displays
membership
Shopping Cart”
shopping cart.
number.
button is selected.
Extension
After Step 3 customer can edit shopping cart
USE CASE: View Customer Account
Description
A staff member can view a customer’s account by accessing the members screen and
searching for the member by membership number.
Pre-Conditions
Post-Conditions
Actor Actions
The staff knows the
The customer’s
1. The actor logs in
customer
account is displayed
(use case 2)
System Response
membership
2. Members tab is
3. Displays Member
number.
selected.
Screen.
4. Membership
5. Members account
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number is entered
is displayed.
into the search bar
and the “Search”
button is pressed.
Extension
After step 5 staff can edit the members account.
USE CASE: Return DVD
Description
Customer returns DVD within the agreed rental period. Staff updates the DVD quantity
information and the customer account.
Pre-Conditions
Post-Conditions
Actor Actions
System Response
The customer must
The customer’s
1. Actor logs in (use
have rented a DVD.
account does not
case 2).
The DVD must be
hold any late fees
2. Actor selects DVD
3. Displays DVD info
returned on or
for that DVD. The
tab
page
before the agreed
DVD has been
4. Actor searches
5. Displays DVD
return date.
returned.
for DVD by DVD ID
information
6. Actor updates
7. Updates quantity
quantity to reflect
available in Stock
returned DVD.
Control for selected
DVD and updates
Customer account
with late fee.
8. Actor accesses
customers account
(use case 5)
9. Returned DVD is
10. Selected DVD is
selected for the
deleted from the
rented list and the
customers rented
“Returned” button
list.
is selected.
Extension
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After step 10, if the DVD was returned late the staff can add a late fee to the customer’s
account
USE CASE: Extend Rental
Description
The customer can extend the rental period of a currently rented DVD by logging into
their members account and extending the rental period. The cost of this extension is
then added to the customer’s account.
Pre-Conditions
Post-Conditions
Actor Actions
System Response
The customer must
The customer has
1. Actor views
have a DVD
extended the rental
account (use case 3)
currently rented.
period for the
2. A DVD currently
3. Select DVD
specific DVD.
rented is selected.
details displayed.
4. Rental period is
5. Extended fee is
extended and the
added to customer
“Update” button is
account and the
pressed.
payment screen is
displayed.
6. Customer pays
7. Customers’
extended rental fee
account screen is
(use case 9)
displayed.
Extension
none
USE CASE: Checkout
Description
After adding DVDs to the shopping cart, the customer then pays for the DVDs by
processing to the checkout.
Pre-Conditions
Post-Conditions
Actor Actions
The customer must
The customer has
1. Actor views
be a member.
paid for rented
shopping cart (use
The customer has
DVDs and the DVDs
case 4).
DVDs in the
will be dispatched.
2. “Checkout”
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System Response
3. Total payment
Page 20
shopping cart.
button is selected.
due displayed.
4. “Pay Now” button
selected (use case
9)
Extension
After Step 3, customer cancels rental.
USE CASE: Pay Fees
Description
Customer pays fees.
Pre-Conditions
Post-Conditions
Actor Actions
The customer must
The customer no
1. Checkout DVDs
be a member.
longer has fees on
(use case 8)
The customer has
account.
2. Credit card
3. Credit card
details entered and
details page
“Pay” button
displayed.
selected.
7. Customers
fees to pay
System Response
account updated to
reflect no
outstanding fees
and customer
account displayed.
Alternative Course
Step 1, access payments screen through extend rental (use case 10).
USE CASE: Pay Outstanding Fees
Description
The customer can pay any outstanding fees obtain by extending rental period or
returning DVD after the agreed rental period, by accessing their account.
Pre-Conditions
Post-Conditions
Actor Actions
The customer must
The customer no
1. Actor views
be a member.
longer has any
account (use case
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System Response
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The customer must
outstanding
3).
3. Outstanding
have outstanding
payments.
2. “Pay Outstanding
payments total
payments on their
Fee” button is
displayed.
account.
selected.
5. Customers
4. “Pay Now” button
account updated to
selected (use case
reflect no
9).
outstanding fees.
Extension
none
USE CASE: Cancel Membership
Description
The customer can cancel their membership by logging into the system and selecting
delete account from the customer account page. The account is then removed from the
customer account system.
Pre-Conditions
Post-Conditions
Actor Actions
The customer must
The customer is no
1. Actor views
be a member.
longer a member.
account (use case 3)
System Response
The customer must
2. “Delete
3. Customer
have no outstanding
Membership”
account is deleted
payments on their
button is pressed.
and customer is
account.
logged out.
Extension
After Step 2, customer has outstanding fees and is redirected to the payment screen.
USE CASE: Delete Member
Description
A staff member can delete a member’s account by accessing the account and deleting the
member.
Pre-Conditions
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Post-Conditions
Actor Actions
System Response
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The customer must
The member
1. Actor views
be a member. The
account has been
customers account
staff must know the
deleted.
(use case 5).
customers’
2.”Delete Account”
3. Members account
membership ID
button is selected.
is deleted.
must be known.
Extension:
none
Pre and Post Conditions OCL:
Context: Member
Pre:
self.memberID exists()
Post: self.memberID  Empty
self.name  Empty
self.Address  Empty
self.Phone  Empty
self.Email  Empty
self.OwnedCart  Empty
USE CASE: Add New DVD Title
Description
A staff member can add a new DVD title to the online store by adding the DVDs details.
Pre-Conditions
Post-Conditions
Actor Actions
The DVD must not
The new DVD is
1. Actor logs in (use
be in the store
added to the store.
case 2)
already.
System Response
2. DVD tab is
3. The DVD
selected.
information screen
is displayed.
4. The relevant DVD
5. The new DVD is
details into the
added to the store.
fields provided
(Name, Type, ID)
and the “Add DVD”
button is selected.
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Extension
none
USE CASE: Update DVD details
Description
When more DVD’s arrive to the store or when DVD’s are returned the quantity of the
DVD must be updated to reflect the quantity currently in the store.
Pre-Conditions
Post-Conditions
Actor Actions
System Response
DVD must be
The quantity of the
1. Actor logs in (use
contained in the
DVD has been
case 2)
system.
updated.
2. The actor selects
3. The DVD screen
DVD tab.
is displayed
4. The actor
5. DVD information
searches for the
is displayed on
DVD by ID.
screen.
7. The DVD details
6. The actor edits
are updated.
the DVD details and
selects the “Update”
button.
Alternative Course
Step 6, DVD type can be changed
Step 6 DVD quantity can be changed
Step 6 DVD can be removed by selecting the remove button.
USE CASE: Update Price
Description
Each type has a fixed price associated with it and this can be changed in the price tab.
Pre-Conditions
Post-Conditions
Actor Actions
The type must exist
The type price is
1. Actor logs in (use
in the system.
updated.
case 2)
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System Response
2. The actor selects
3. The price screen
the “Price” tab.
is displayed.
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4. The actor selects
5. The price for the
the price, edits the
selected type is
amount and selects
updated.
the “Update” button.
Alternative Course
Step 4 The standard rental price is updated.
Step 4 The late rental price is updated.
Step 4 The extend rental price is updated.
Step 4 The type rental price is updated.
NON-FUNCTIONAL
Non-Functional Requirement
Description
Availability
As the DVD rental system is online it must be
available to the customer at all times.
Quality
The DVD rental system fulfils the customers’
expectations by conforming to the customer’s
requirements of renting a DVD online.
Reliability
The system is reliable as the required databases are
backed up nightly in case of a system failure.
Scalability
The database for system use will often need to be
increased in size as more DVD’s are added. For this
reason it needs to be easily scalable.
Usability
As customers utilize this system the user- interface
needs to be quite intuitive to use and user friendly.
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USE CASE DIAGRAMS
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GUI PROTOTYPES
STAFF USER INTERFACE PROTOTYPES
Adding, Updating and Deleting Types and Price Details UI
Adding, Updating, Viewing and Deleting DVDs UI
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Adding, Updating, Viewing and Deleting Member Details UI
MEMBER USER INTERFACE PROTOTYPES
Browse DVDs
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Create a Rental
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View Cart
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ANALYSIS
CANDIDATE OBJECTS
The noun identification method was chosen to identify the candidate objects.
Renting a DVD
A customer must first be a member of the store to rent a DVD. When the member logs in,
they can browse through a selection of DVDs and add them to a virtual shopping cart.
The cart cannot contain more than three rentals at a time. Each DVD is a different price
depending on its type and rental period. When the member is satisfied with their
selection, the member can proceed to pay for their rentals.
Update DVD details
A staff member can update a DVD’s details by searching for the DVD on the system. The
staff member can then change this information and save the changes.
Candidate Objects
Member
DVD
Cart
Rental
Price
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CLASS DIAGRAM
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SEQUENCE DIAGRAM
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COMMUNICATION DIAGRAM
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STATE CHART
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ENTITY RELATIONSHIP DIAGRAM
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DESIGN
ARCHITECTURAL STYLE
After examining the class diagram created in the analysis phase, it was clear that a more
structured approach should be taken in order to reduce the complexity and
dependencies within the system. This involved introducing structural and behavioral
patterns. The structural patterns chosen were the Proxy Pattern which was applied to
the Data Management package and the façade pattern which was applied to the Entity
interfaces. The behavioral pattern chosen was the State Pattern which was applied to
the Cart Object. The Model-View-Controller pattern was also applied to the entire
system.
MODEL-VIEW-CONTROLLER PATTERN
INTENT: Support user requirements that are presented through different interface styles
and aids maintainability and portability.
PROBLEM: The same information should be capable of presentation in different formats in
different windows. Changes within one view should be reflected immediately in the other
views. Changes in the user interface should be easy to make. Core functionality should be
independent of the interface to enable multiple interface styles to co-exist.
SOLUTION: Separate the core functionality (model) from the interface and through its
incorporation of a mechanism for propagating updates to other views. The interface itself is
split into two elements: the output presentation (view) and the input controller (controller).
[3]
The model-view-controller pattern was applied to the entire class diagram. This
grouped the classes into three main components: models that comprise of the main
functionality, views that present the user interface and controllers that manage the
updates to views.
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STATE PATTERN
INTENT: Allow an object to alter its behavior when it’s internal state changes. The object
will appear to change class.
PROBLEM: An object exhibits different behavior when its internal state changes, making it
appear that the object changes class at runtime.
SOLUTION: Separate the state dependant behavior from the original class.
[1]
The cart object can be in one of four states. These states change dynamically as DVDs
are added and removed from the cart. Changing the state of the cart changes the
behavior of the object. As the cart has a state dependant behavior it was decided to
apply the state pattern to the object. Applying the state pattern to the cart object
reduces the amount of if-else statements. It also created a new class for each state which
holds a state-specific version of the operations.
PROXY PATTERN
INTENT: Provides a proxy object as a placeholder for another object until it is required.
PROBLEM: The way a persistent objects maintain a reference to other objects.
SOLUTION: Use a proxy for each business class to link to where there is an association with
another object or objects.
[1]
A database broker framework was designed to control the data required by the various
objects. It purpose is to separate the business objects from the data storage
implementation. A broker class was used for every business class that is persistent as it
provides the mechanism to materialize and dematerialize objects to and from the
database. The proxy pattern was then applied to this framework. The proxy holds a
private instance of the real object; clients then execute actions on the proxy which are
passed to the real object. The results from the real object are returned to the client via
the proxy.
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FAÇADE PATTERN
INTENT: Provide a unified interface to a set of interfaces in a subsystem. Façade defines a
higher level interface that makes the system easier to use.
PROBLEM: Need to minimize communications and dependencies.
SOLUTION: Structuring a system into subsystems helps to reduce complexity and providing
a simple interface.
[1]
The façade pattern was chosen to reduce the complexity of the system. The façade
pattern was used with the Model-View-Controller pattern and was applied to the model
components. This pattern was implemented by providing an interface that
communicates with all subsystem interfaces. The view and the controller then
communicate with this interface which reduces the complexity of the overall system.
Figure 1 The Façade pattern [3]
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CLASS DIAGRAM INCLUDING MVC
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STAFF PACKAGE
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MEMBER PACKAGE
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CART PACKAGE
RENTAL PACKAGE
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DVD PACKAGE
PRICE PACKAGE
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SEQUENCE DIAGRAM INCLUDING MVC
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DEPLOYMENT DIAGRAM
The Deployment diagram shows a PC Client which is connected to a server. The Server
holds all of the java archive files for the MemberManagement package, Rental
Management Package, DVDManagement package, Cart Package, Staff Management
package and the PriceManagement package. These are all held on a server as they will
all need to be accessed by the customers through means of a browser application which
is held in the client (Referred to in the diagram by ClientApplication.jar). The means of
connection from client to server is by TCP/IP.
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DATA DICTIONARY
Name:
Administrator
Type:
Actor
Description: The Administrator is the role of the staff member uses the system and is
responsible for a number of different operations to do with the day to day running of
the store. These operations include:
1. Updating the price, genre, type of DVDs there are in store,
2. Adding new DVDs to the system and
3. Deleting DVDs, Members etc.
Name:
Member
Type:
Actor
Description: The Member represents a member of the store, a customer who can
interact with the system and perform various operations such as:
Renting DVDs
Extending the DVD rental period
Browsing for DVDs
Name:
Credit Card Company
Type:
Actor
Description: The Credit Card Company is an external actor, which deals with the
payments from members credit cards for rentals.
Name:
Rentals
Type:
Logical Entity
Description: The Rental Entity is used to store information about the various Rentals
of DVDs that exist.
Entity Relationships: Rental is contained in a Cart and requires a DVD.
Name:
DVD
Type:
Logical Entity
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Description: The DVD Entity is used to store information about the various DVD’s that
ClickDVD stores. Entity Relationships: DVD has a price and is required by Rental.
Name:
Cart
Type:
Logical Entity
Description: The Cart Entity is used to store information about the Carts used by the
members when choosing DVDs to rent.
Entity Relationships: Cart contains Rental, and is owned by a member.
Name:
CartState
Type:
Abstract Class
Description: The Cart can be in three different states. Active, Full, and Complete. The
Cart State abstract class is used to show which methods are implemented in the Active,
Full and Complete Classes.
Name:
isPaid
Type:
Boolean
Description: The isPaid value is set to true when the credit card company validate the
credit card payment. When this value is true, the cart state changes to paid.
Name:
Price
Type:
Logical Entity
Description: The Price is used to store the different prices and points for each
DVD. Different types of DVD have different prices. The three different types of DVD are
New Release, Regular, and Children’s.
Name:
Member
Type:
Logical Entity
Description: The Member is used to store information about the various members of
ClickDVDs. Such info includes: name address, ID, Phone and Email address.
Entity Relationships: Member owns a Cart.
Name:
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DVDManageable
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Type:
Interface
Description: The DVDManageable interface provides the functionality needed for the
staff to manage the DVDs, for example adding or removing a DVD.
Name:
DVDViewable
Type:
Interface
Description: The DVDViewable interface provides the functionality needed for the
members to view DVDs.
Name:
RentalCollection
Type:
Collection Class
Description: The RentalCollection class provides a collection of Rentals which can be
accessed by the Cart. A Cart contains a collection of Rentals.
Name:
database [DataManagement]
Type:
Attribute
Description: Used to represent the database which is used to hold the data for use in
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Name:
MemberManageable
Type:
Interface
Description: The MemberManageable interface provides the functionality needed for
the staff to manage the Members, for example, viewing, updating or removing a
Member.
Name:
MemberAccount
Type:
Interface
Description: The MemberAccount interface provides the functionality needed for the
members to view their own accounts. Here they can delete their account, view, and
update their account. As well as extend rentals currently occurring.
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REFERENCES
1. Bennett, S., et al. (2006). Object-Orientated Systems Analysis and Design, 3rd
Edition. McGraw Hill
2. Fowler, M. (2006). UML DISTILLED THIRD EDITION. Addison-Wesley
3. Gamma, E., et al. (1995). Design Patterns. Addison-Wesley
4. http://www.as3dp.com/2009/02/14/design-pattern-principles-foractionscript-30-program-to-an-interface-not-an-implementation/ Programming
to interfaces not implementation. [Accessed 24-04-2009]
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