Chapter 13 Configuring the Object Request Broker
This chapter describes how to configure the Object Request Broker (ORB) and IIOP listeners. It has the following sections:
CORBA
The Application Server supports a standard set of protocols and formats that ensure interoperability. Among these protocols are those defined by CORBA.
The CORBA (Common Object Request Broker Architecture) model is based on clients requesting services from distributed objects or servers through a well-defined interface by issuing requests to the objects in the form of remote method requests. A remote method request carries information about the operation that needs to be performed, including the object name (called an object reference) of the service provider and parameters, if any, for the invoked method. CORBA automatically handles network programming tasks such as object registration, object location, object activation, request de-multiplexing, error-handling, marshalling, and operation dispatching.
What is the ORB?
The Object Request Broker (ORB) is the central component of CORBA. The ORB provides the required infrastructure to identify and locate objects, handle connection management, deliver data, and request communication.
A CORBA object never talks directly with another. Instead, the object makes requests through a remote stub to the ORB running on the local machine. The local ORB then passes the request to an ORB on the other machine using the Internet Inter-Orb Protocol (IIOP for short). The remote ORB then locates the appropriate object, processes the request, and returns the results.
IIOP can be used as a Remote Method Invocation (RMI) protocol by applications or objects using RMI-IIOP. Remote clients of enterprise beans (EJB modules) communicate with the Application Server via RMI-IIOP.
IIOP Listeners
An IIOP listener is a listen socket that accepts incoming connections from the remote clients of enterprise beans and from other CORBA-based clients. Multiple IIOP listeners can be configured for the Application Server. For each listener, specify a port number, a network address, and optionally, security attributes.
Working with the ORB
To create an IIOP listener, select Configuration > ORB > IIOP Listeners and click New in the Admin Console. Alternatively, you can use the following asadmin command to create IIOP listeners: create-iiop-listener(1) and create-ssl(1).
To edit an IIOP listener, select Configuration > ORB > IIOP Listeners and select the listener to be modified in the Admin Console. Modify the settings. If you have changed the port number, restart the server. The ORB uses thread pools to respond to requests from remote clients of enterprise beans and other clients that communicate via RMI-IIOP.
To delete an IIOP listener, select Configuration > ORB > IIOP Listeners and select the listener to be deleted in the Admin Console. Alternatively, you can use the delete-iiop-listener(1) command.
The ORBCommunicationsRetryTimeout property specifies the number of seconds the ORB client will try to establish a connection to an unreachable ORB back-end. The default value is 60 seconds. With this default setting, you may see a large number of CORBA exceptions in the logs, as well as high network usage if the ORB back-end is not reachable.
In such cases, set the ORBCommunicationsRetryTimeout to a lower value.
Third-party ORBs
The Sun Java System Application Server can be used in conjunction with third-party ORB software. To support such third-party ORBs, you need to revise the server-side settings.
To implement the support for a third-party ORB in Application Server, you need to edit the files, domain.xml and server.policy. For detailed instructions on how to configure a sample third-party ORB, see Configuring Sun Java System Application Server for Third-Party ORBs
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