Configured name bindings
Administrators can configure bindings into the namespace. A configured binding is different from a programmatic binding in that the system creates the binding every time a server is started, even if the target context is in a transient partition.
Administrators can add name bindings to the namespace through the configuration. Name servers add these configured bindings to the namespace view, by reading the configuration data for the bindings. Configuring bindings is an alternative to creating the bindings from a program. Configured bindings have the advantage of being created each time a server starts, even when the binding is created in a transient partition of the namespace. Cell-scoped configured bindings provide a fixed qualified name for server application objects.
Scope
You can configure a binding at one of the following four scopes: cell, node, server, or cluster. Cell-scoped bindings are created under the cell persistent root context. Node-scoped bindings are created under the node persistent root context for the specified node. Server-scoped bindings are created under the server root context for the selected server. Cluster-scoped bindings are created under the server root context in each member of the selected cluster.
The scope you select for new bindings depends on how the binding is to be used. For example, if the binding is not specific to any particular node, cluster, or server, or if you do not want the binding to be associated with any specific node, cluster, or server, a cell-scoped binding is a suitable scope. Defining fixed names for enterprise beans to create fixed qualified names is just such an application. If a binding is to be used only by clients of an application running on a particular server (or cluster), or if you want to configure a binding with the same name on different servers (or clusters) which resolve to different objects, a server-scoped (or cluster-scoped) binding would be appropriate. Note that two servers or clusters can have configured bindings with the same name but resolve to different objects. At the cell scope, only one binding with a given name can exist.
Intermediate contexts
Intermediate contexts
created with configured bindings are read-only. For example, if an
EJB home binding is configured with the name some/compound/name/ejbHome
,
the intermediate contexts some
, some/compound
,
and some/compound/name
will be created as read-only
contexts. You cannot add, update, or remove any read-only bindings.
The
configured binding name cannot conflict with existing bindings. However,
configured bindings can use the same intermediate context names. Therefore,
a configured binding with the name some/compound/name2/ejbHome2
does
not conflict with the previous example name.
Configured binding types
Types of objects that you can bind follow:
- EJB: EJB home installed in some server in the cell
- The following data is required to configure an EJB home binding:
- JNDI name of the EJB server or server cluster where the enterprise bean is deployed
- Target root for the configured binding (scope)
- The name of the configured binding, relative to the target root.
A cell-scoped EJB binding is useful for creating a fixed lookup name for an enterprise bean so that the qualified name is not dependent on the topology.
Note: In stand-alone servers, an EJB binding resolving to another server cannot be configured because the name server does not read configuration data for other servers. That data is required to construct the binding. - CORBA: CORBA object available from some CosNaming name server
- You can identify any CORBA object bound into some INS compliant
CosNaming server with a corbaname URL. The referenced object does
not have to be available until the binding is actually referenced
by some application.
The following data is required in order to configure a CORBA object binding:
- The corbaname URL of the CORBA object
- An indicator if the bound object is a context or leaf node object (to set the correct CORBA binding type of context or object)
- Target root for the configured binding
- The name of the configured binding, relative to the target root
- Indirect: Any object bound in WebSphere® Application Server namespace accessible with JNDI
- Besides CORBA objects, this includes javax.naming.Referenceable,
javax.naming.Reference, and java.io.Serializable objects. The target
object itself is not bound to the namespace. Only the information
required to look up the object is bound. Therefore, the referenced
name server does not have to be running until the binding is actually
referenced by some application. The following data is required in
order to configure an indirect JNDI lookup binding:
- JNDI provider URL of name server where object resides
- JNDI lookup name of object
- Target root for the configured binding (scope)
- The name of the configured binding, relative to the target root.
A cell-scoped indirect binding is useful when creating a fixed lookup name for a resource so that the qualified name is not dependent on the topology. You can also achieve this topology by widening the scope of the resource definition.
- String: String constant
- You can configure a binding of a string constant. The following
data is required to configure a string constant binding:
- String constant value
- Target root for the configured binding (scope)
- The name of the configured binding, relative to the target root