Chapter 20 Administering the Java Naming and Directory Interface (JNDI) Service

The Java Naming and Directory Interface (JNDI) API is used for accessing different kinds of naming and directory services. Java EE components locate objects by invoking the JNDI lookup method.

The following topics are addressed here:

• About JNDI

• Administering JNDI Resources

Instructions for accomplishing the tasks in this chapter by using the Administration Console are contained in the Administration Console online help.

About JNDI

By making calls to the JNDI API, applications locate resources and other program objects. A resource is a program object that provides connections to systems, such as database servers and messaging systems. A JDBC resource is sometimes referred to as a data source. Each resource object is identified by a unique, people-friendly name, called the JNDI name. A resource object and its JNDI name are bound together by the naming and directory service, which is included with the Enterprise Server.

When a new name-object binding is entered into the JNDI, a new resource is created.

The following topics are addressed here:

• J2EE Naming Environment

• How the Naming Environment and the Container Work Together

• Naming References and Binding Information

J2EE Naming Environment

JNDI names are bound to their objects by the naming and directory service that is provided by a J2EE server. Because J2EE components access this service through the JNDI API, the object usually uses its JNDI name. For example, the JNDI name of the PointBase database is jdbc/Pointbase. At startup, the Enterprise Server reads information from the configuration file and automatically adds JNDI database names to the name space, one of which is jdbc/Pointbase.

Java EE application clients, enterprise beans, and web components must have access to a JNDI naming environment.

The application component's naming environment is the mechanism that allows customization of the application component's business logic during deployment or assembly. This environment allows you to customize the application component without needing to access or change the source code off the component. A Java EE container implements the provides the environment to the application component instance as a JNDI naming context.

How the Naming Environment and the Container Work Together

The application component's environment is used as follows:

• The application component's business methods access the environment using the JNDI interfaces. In the deployment descriptor, the application component provider declares 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 JNDI context available to the application component instances at runtime. These 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. For example, jdbc/SavingsAccountDB. More specifically, the coded name references a connection factory for the resource.

The JNDI name of a resource and the resource reference name 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 decoupling, if at a later time the component needs to access a different resource, the name does not need to change. This flexibility makes it easier for you to assemble J2EE applications from preexisting components.

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

Administering JNDI Resources

Within Enterprise Server, you can configure your environment for custom and external JNDI resources. A custom resource accesses a local JNDI repository; an external resource accesses an external JNDI repository. Both types of resources need user-specified factory class elements, JNDI name attributes, and so on.

• Administering Custom JNDI Resources

• Administering External JNDI Resources

Administering Custom JNDI Resources

A custom resource specifies a custom server-wide resource object factory that implements the javax.naming.spi.ObjectFactory interface. The following topics are addressed here:

• To Create a Custom JNDI Resource

• To List Custom JNDI Resources

• To Update a Custom JNDI Resource

• To Delete a Custom JNDI Resource

To Create a Custom JNDI Resource

Use the create-custom-resource subcommand in remote mode to create a custom resource.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. Create a custom resource by using the create-custom-resource(1) subcommand.

   Information on properties for the subcommand is contained in this help page.

3. Restart Enterprise Server.

   See To Restart a Domain.

Example 20–1 Creating a Custom Resource

This example creates a custom resource named sample-custom-resource.

asadmin> create-custom-resource --restype topic --factoryclass com.imq.topic 
sample_custom_resource
Command create-custom-resource executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help create-custom-resource at the command line.

To List Custom JNDI Resources

Use the list-custom-resources subcommand in remote mode to list the existing custom resources.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. List the custom resources by using the list-custom-resources(1) subcommand.

Example 20–2 Listing Custom Resources

This example lists the existing custom resources.

asadmin> list-custom-resources
sample_custom_resource01 
sample_custom_resource02 
Command list-custom-resources executed successfully

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help list-custom-resources at the command line.

To Update a Custom JNDI Resource

1. List the custom resources by using the list-custom-resources(1) subcommand.

2. Use the set(1) subcommand to modify a custom JNDI resource.

Example 20–3 Updating a Custom JNDI Resource

This example modifies a custom resource.

asadmin> set server.resources.custom-resource.custom
/my-custom-resource.property.value=2010server.resources.custom-resource.custom
/my-custom-resource.property.value=2010

To Delete a Custom JNDI Resource

Use the delete-custom-resource subcommand in remote mode to delete a custom resource.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. List the custom resources by using the list-custom-resources(1) subcommand.

3. Delete a custom resource by using the delete-custom-resource(1) subcommand.

Example 20–4 Deleting a Custom Resource

This example deletes a custom resource named sample-custom-resource.

asadmin> delete-custom-resource sample_custom_resource
Command delete-custom-resource executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help delete-custom-resource at the command line.

Administering External JNDI Resources

Applications running on Enterprise Server often require access to resources stored in an external JNDI repository. For example, generic Java objects might be stored in an LDAP server according to the Java schema. External JNDI resource elements let you configure such external resource repositories.

The following topics are addressed here:

• To Register an External JNDI Resource

• To List External JNDI Resources

• To List External JNDI Entries

• To Update an External JNDI Resource

• To Delete an External JNDI Resource

• Example of Using an External JNDI Resource

To Register an External JNDI Resource

Use the create-jndi-resource subcommand in remote mode to register an external JNDI resource.

Before You Begin

The external JNDI factory must implement the javax.naming.spi.InitialContextFactory interface.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. Register an external JNDI resource by using the create-jndi-resource(1) subcommand.

   Information on properties for the subcommand is contained in this help page.

3. Restart Enterprise Server.

   See To Restart a Domain.

Example 20–5 Registering an External JNDI Resource

In This example sample_jndi_resource is registered.

asadmin> create-jndi-resource --jndilookupname sample_jndi 
--restype queue --factoryclass sampleClass --description "this is a sample jndi 
resource" sample_jndi_resource
Command create-jndi-resource executed successfully

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help create-jndi-resource at the command line.

To List External JNDI Resources

Use the list-jndi-resources subcommand in remote mode to list all existing JNDI resources.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. List the existing JNDI resources by using thelist-jndi-resources(1) subcommand.

Example 20–6 Listing JNDI Resources

This example lists the JNDI resources.

asadmin> list-jndi-resources
jndi_resource1
jndi_resource2
jndi_resource3
Command list-jndi-resources executed successfully

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help list-jndi-resources at the command line.

To List External JNDI Entries

Use the list-jndi-entries subcommand in remote mode to browse and list the entries in the JNDI tree. You can either list all entries, or you can specify the JNDI context or subcontext to list specific entries.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. List the JNDI entries for a configuration by using the list-jndi-entries(1) subcommand.

Example 20–7 Listing JNDI Entries

This example lists all the JNDI entries for the naming service.

asadmin> list-jndi-entries
jndi_entry03
jndi_entry72
jndi_entry76
Command list-jndi-resources executed successfully

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help list-jndi-entries at the command line.

To Update an External JNDI Resource

1. List the existing JNDI resources by using thelist-jndi-resources(1) subcommand.

2. Use the set(1) subcommand to modify an external JNDI resource.

Example 20–8 Updating an External JNDI Resource

This example modifies an external resource.

asadmin> set server.resources.external-jndi-resource.my-jndi-resource.
jndi-lookup-name=bar server.resources.external-jndi-resource.my-jndi-resource.jndi-lookup-name=bar 

To Delete an External JNDI Resource

Use the delete-jndi-resource subcommand in remote mode to remove a JNDI resource.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. Remove an external JNDI entry by using the delete-jndi-resource(1) subcommand.

Example 20–9 Deleting an External JNDI Resource

This example deletes an external JNDI resource:

asadmin> delete-jndi-resource jndi_resource2
Command delete-jndi-resource executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help delete-jndi-resource at the command line.

Example of Using an External JNDI Resource

<resources>
 <!-- external-jndi-resource element specifies how to access J2EE resources
 -- stored in an external JNDI repository. This example
 -- illustrates how to access a java object stored in LDAP.
 -- factory-class element specifies the JNDI InitialContext factory that
 -- needs to be used to access the resource factory. property element
 -- corresponds to the environment applicable to the external JNDI context
 -- and jndi-lookup-name refers to the JNDI name to lookup to fetch the
 -- designated (in this case the java) object.
 -->
  <external-jndi-resource jndi-name="test/myBean"
      jndi-lookup-name="cn=myBean"
      res-type="test.myBean"
      factory-class="com.sun.jndi.ldap.LdapCtxFactory">
    <property name="PROVIDER-URL" value="ldap://ldapserver:389/o=myObjects" />
    <property name="SECURITY_AUTHENTICATION" value="simple" />
    <property name="SECURITY_PRINCIPAL", value="cn=joeSmith, o=Engineering" />
    <property name="SECURITY_CREDENTIALS" value="changeit" />
  </external-jndi-resource>
</resources>