In this exercise, you create the Display Balance participants diagram. The Display Balance participants diagram models the static structure of the Display Balance use case.
The Display Balance participants diagram shows the classes that participate in the Display Balance use case. You model the participants, along with their attributes and relationships, to describe the domain of the system. In addition to entities, this diagram describes the boundary classes that interact with the main entity classes to complete the functional task. A menu and a computer interface are examples of boundary classes.
Modeling is an iterative process. You can add, remove, or modify particpants at any time as you better understand the details of the system that you are modeling. In this tutorial, you create the basic outline of the Display Balance participants diagram. You add to this diagram as you model the dynamic structure of the use case.
You create the Display Balance participants diagram in the Account Operations package.
You have created the Account participant by dragging the Account model element that was created in the domain diagram exercise. The Account participant is the only element in the Display Balance Participant diagram.
The DisplayBalanceForm participant represents a boundary class that exists between the main PiggyBank main menu and the Account class.
You have just modeled the DisplayBalanceForm boundary particpant. The DisplayBalanceForm class has a single relationship to the Account class. Your diagram should look similar to the following figure:
The MenuForm participant is a boundary class that represents the main menu of the PiggyBank system. The MenuForm participant interacts with the DisplayBalanceForm participant
You have created the basic structure of the Display Balance Participants diagram. The diagram shows the structure of the participants in the functional task, as well as their relationships. Your diagram should look similar to the following figure:
Modeling the static structure of the Display Balance use case provides you with a better understanding of the main classes that participate in the use case. After you understand the main class structure, you can model the workflow of the use case by creating the Display Balance sequence diagram. When you create the Display Balance sequence diagram, you identify the operations of each entity in the use case. The sequence diagram can help you to better understand the data flow in the use case.
To continue, proceed to Exercise 2.6: Creating the Display Balance sequence diagram.