8.1 Introduction to Application Modules

An application module is Oracle ADF Business Component component that encapsulates the business service methods and active data model for a logical unit of work related to an end-user task.

By the end of this chapter, you'll understand all the concepts illustrated in Figure 8-1, and more:

• You use instances of view objects in an application module to define its active data model.

• You write service methods to encapsulate task-level business logic.

• You expose selected methods on the service interface for clients to call.

• You use application modules from a pool during a logical transaction that can span multiple web pages.

• Your application module works with a Transaction object that acquires a database connection and coordinates saving or rolling back changes made to entity objects.

• The related Session object provides runtime information about the current application user

Figure 8-1 Application Module Is a Business Service Component Encapsulating a Unit of Work

Previous chapters explained the details of including view object instances in an application module's data model and of how client-accessible view objects cooperate internally with the entity objects in your reusable business domain layer. This chapter describes how to combine business service methods with that data model to implement a complete business service.

Note: The examples in this chapter use the same basic SRService application module from Chapter 7, "Building an Updatable Data Model With Entity-Based View Objects", including the entity-based view objects shown in Figure 8-1. To experiment with a working version, download the DevGuideExamples workspace from Example Downloads page at http://otn.oracle.com/documentation/jdev/b25947_01 and see the ApplicationModules project.