Special Edition Using Enterprise JavaBeans 2.0

   

Deployer Responsibilities

Part of the deployer's job is to complete any deployment information that wasn't supplied by the application assembler. There also might be changes needed to environment entries that were supplied but don't reflect the true target environment. The deployer must ensure that all EJBs referenced by the application are present in the environment and that all required resources are available and accessible.

Much of what the deployer must do is outside the bounds of entering data into the deployment descriptor. The deployer is instead responsible for using tools specific to the application server and the rest of the target environment to support the references declared in the descriptor. For example, the deployer must bind data sources to any connection factory references that exist. If the authorization method for a resource ( res-auth ) is specified as Container , the deployer must also supply the necessary login information. Any referenced administered objects, such as JMS queues or topics, must be configured and made available to the application as well.

A significant responsibility of the deployer is to take the logical security roles specified by the application assembler and map them to the actual security domain of the target environment. This includes assigning the principals and groups recognized by the target environment to the application assembler's security roles. Security topics are discussed in more detail in Chapter 14, "Security Design and Management."

The important point to remember about the work of the deployer is that much of it is vendor specific. The deployer will often be working with supplemental deployment files, such as WebLogic's weblogic-ejb-jar.xml file, and other configuration data used by the application server to bind an EJB application to the resources and security mechanisms it requires.

Note

Vendors typically will have a different name for their proprietary deployment descriptor. For example, the deployment descriptor for the Orion EJB server is called orion-ejb-jar .xml .

Summary of Responsibilities

Table 15.4 summarizes the deployment responsibilities assigned to each of the applicable EJB roles.

Table 15.4. Deployment Responsibilities by EJB Role

EJB Role

Responsibilities

Bean provider

All source code. The preliminary ejb-jar.xml file identifying the beans, their relationships, any resource and environment dependencies, and so on.

Application assembler

The assembly-descriptor section of ejb-jar.xml , including elements defining security roles, method permissions, and transaction attributes. The assembler also can supply values for any environment entries not already defined. The purpose of this role is to define the behavior of one or more beans when used as part of a particular application.

Deployer

The contents of any vendor-specific deployment descriptors. The deployer must finalize all deployment information and create the JAR (and possible WAR and EAR) files needed to deploy the application in the target environment. This includes satisfying any resource and security dependencies of the deployed beans.

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