Sun Microsystems 820433510 manual Naming References and Binding Information

Naming References and Binding Information

application component's environment allows the application component to be customized without the need to access or change the application component's source code.

A Java EE container implements the application component's environment, and provides it to the application component instance as a JNDI naming context. The application component's environment is used as follows:

■The application component's business methods access the environment using the JNDI interfaces. The application component provider declares in the deployment descriptor all the environment entries that the application component expects to be provided in its environment at runtime.

■The container provides an implementation of the JNDI naming context that stores the application component environment. The container also provides the tools that allow the deployer to create and manage the environment of each application component.

■A deployer uses the tools provided by the container to initialize the environment entries that are declared in the application component's deployment descriptor. The deployer sets and modifies the values of the environment entries.

■The container makes the environment naming context available to the application component instances at runtime. The application component's instances use the JNDI interfaces to obtain the values of the environment entries.

Each application component defines its own set of environment entries. All instances of an application component within the same container share the same environment entries. Application component instances are not allowed to modify the environment at runtime.

Naming References and Binding Information

A resource reference is an element in a deployment descriptor that identifies the component’s coded name for the resource. More specifically, the coded name references a connection factory for the resource. In the example given in the following section, the resource reference name is jdbc/SavingsAccountDB.

The JNDI name of a resource and the name of the resource reference are not the same. This approach to naming requires that you map the two names before deployment, but it also decouples components from resources. Because of this de-coupling, if at a later time the component needs to access a different resource, the name does not need to change. This flexibility also makes it easier for you to assemble J2EE applications from preexisting components.

The following table lists JNDI lookups and their associated references for the J2EE resources used by the Enterprise Server.

78 Sun GlassFish Enterprise Server 2.1 Administration Guide • December 2008