Activity Diagram for the ATM System

An activity diagram is a great way to visualize the flow of messages from one activity to the other in the system. There can be different activity diagrams that we can create for our ATM. In this lesson, we will create activity diagrams for the following two activities:

• The cardholder performs ATM transactions.

• Activity challenge: The cardholder performs an ATM cash withdrawal.

The cardholder performs ATM transactions#

The followings are the states and actions that will be involved in this activity diagram.

States#

Initial state: The cardholder inserts an ATM card.

Final state: There are two final states in this activity diagram as shown below:

• The cardholder gets an error message for the wrong ATM PIN.

• The cardholder performs a transaction successfully.

Actions#

The cardholder approaches the ATM, inserts their card, and enters their PIN. If the PIN is correct, they are allowed to perform a transaction. If the PIN is incorrect, the ATM returns the card. The cardholder then has the option to select from four different transactions. After completing their chosen transaction, the cardholder receives their card back from the ATM.

Based on the order above, the activity diagram is given below.

Activity challenge: The cardholder performs an ATM cash withdrawal#

You’ll help us create an activity diagram of a cardholder performing an ATM cash withdrawal.

The skeleton of the activity diagram is shown below.

Notice that the actions in the diagram above are numbered from 1 to 6. The slots shown below represent the activities, and the arrows represent the flow from one activity to the other. Can you rearrange the slots below in the correct order they should appear in the activity diagram above?

Note: If you are unsure, click the “Show Solution” button for the correct answer.

Alternatively, click the "Show complete diagram" button below to see the complete sequence diagram:

We've looked at some of the activity diagrams of our ATM. In the next lesson, we will present the code for our designed classes in some of the most popular languages.