UML Case Study: Easy Payment Gateway and Mobile Wallet

This UML case study explores the use of easy payment gateway and mobile wallet methods in ecommerce online applications. It includes activity and sequence diagrams, as well as screen designs.

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Figure 1 Activity diagram for easy payment gateway use case

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Figure 2 Activity diagram for mobile wallet use case

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Figure 3 Sequence diagram for easy payment gateway use case
Figure 4 Sequence diagram for mobile wallet use case
The diagrams shown above describes the use cases selected for the case study. The
case study taken in this assignment is the payment system and the activities associated in e-
commerce online applications. In this assignment, the two extended use cases selected are the
two different types of popular payments method used nowadays. The first use case is the easy

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payment gateway method and the second use case is the mobile wallet method. Both these
methods have different activities associated with them and has some common aspects as well.
For example, both these methods use the credit or debit card information to finalise the
payment and requests approval from the user. Once approved then only they proceed with the
transactions. The mobile wallet is a newer feature as is more complex than a simple easy
payment gateway.
In this first use case, the method chosen for paying in the payment system case study
is online payment gateway. In this method, first the user requests for the payment via the
application interface. After confirming the items and the amount in the cart the application
forwards them to the details page where the card information of the client needs to be
entered. Once the information is verified, the client sends the information to the bank for
validating. The bank sends back a OTP to the user in his personal mobile phone to authorise
and validate the user. After this the bank authorises the transaction and the payment is
processed. Finally the bank sends back the receipt or response for the payment request back
to the customer. The sequence diagram and the activity diagrams provides a more proper
understanding of this process.
The second use case, the method chosen is the mobile wallet payment method. In this
method, the payment is done via the mobile wallet option in which the customer gets to pay
the amount in the cart after checkout directly from their preferred mobile wallet platform. For
example, once a user checkout out of their shopping cart, he or she may select the mobile
wallet option from the payment selection screen. This is an increasingly common option of
payment that leads to easy shopping via mobile applications without need of carrying all their
debit or credit cards. The payment request travels to the payment controller and then to
selected mobile wallet’s service provider. The payment data is encrypted in the form of a
token and send to the payment service gateway which transform the request and

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automatically uses the saved card information to proceed with the payment after a mandatory
authorisation check from the customer. Once approved by the user, the mobile wallet
automatically proceeds with the payment via the payment gateway and once the payment is
completed and process, the receipt of the payment is send back to the client. This method is
very secure due to the encryption involved.
The extended use cases are:
1. Easy payment gateway
Actors: Customer, bank
Aim: To complete the payment using the easy payment gateway
Trigger: User selects an option to complete the payment process.
Main flow:
1. Select payment method.
2. Enter payment card information.
3 Enter OTP received.
4. Authorize and complete payment.
2. Mobile wallet method
Actors: Customer, bank, mobile wallet service provider
Aim: To complete the payment via mobile wallet application.
Trigger: User selects an option to complete the payment process.
Main flow:
1. Select payment method.
2. Confirm payment in the mobile wallet app.

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3. Authorise payment via OTP/email.
4. Complete payment and generate receipt.
The screen designs are shown for the use case easy payment gateway which requires the
user to enter their credit/debit/ATM card information in order to proceed with the payment. A
screen showing the cart before checkout is also shown here. Another screen shows the
payments method available for payment after checkout.
The screen images are shown here as below in the next page

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Figure 5 Cart screen before checkout

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Figure 6 Payment selection screen after checkout

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Figure 7 Easy payment gateway enter card information screen