Job Ready Java

Lesson 29Pulling It All Together: Coding the Class Roster Service Layer

It's time again to pull together what we've learned by implementing the Class Roster service layer that we designed in the previous lesson into an application. We will continue with the Class Roster application we updated in Lesson 27.

PROGRAM OBJECTIVES

Essentially, we will be coding the business rules into our application by following these steps:

• Create the service layer interface.
• Create new application-specific exceptions.
• Refactor/rename the existing ClassRosterDaoException.
• Implement the service layer interface.
• Modify the controller to use the new service layer.
• Modify the dependency injection code in App to account for the new service layer component.
• Add the audit log feature.
  • Create the Audit DAO interface.
  • Create the Audit DAO file implementation.
  • Modify the service layer to use the Audit DAO.
  • Modify the dependency injection code in App to account for the new Audit DAO component.

CREATE A SERVICE LAYER INTERFACE

The first step in updating our Class Roster application is to create the service layer interface that we designed in the previous lesson. We are going to have several classes and interfaces related to our service layer, so we will create a new com.sg.classroster.service package in the same way we've added packages before. To do this, open the ClassRoster project, right-click the com.sg.classroster package, and select New ➢ Java Package, as shown in Figure 29.1.

Figure ...