COPARISON OF UTILITIES IN CORBA PRODUCTS
(This list covers  BEA WebLogic Enterprise(Formerly BEA M3), Visibroker for Java and Sun Microsystem's packeges CORBA and RMI.)
(Note: This is page is still undergoing  improvements)

Compiled by Channu Kambalyal

Purpose: The purpose of making this list is to provide the the Corba Software Developer with exposure to the Utilities provided by Various Corba Products. With this list in hand one can quickly grasp what utilitiy of one product relates to that of the other product. This list also provides the features provided or not provided by the products. For more accurate and latest details on the product user should refer to the Vendor's Documetation.
 
CORBA UTILITY

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BEA WebLogic Enterprise (Formarly BEA M3)
for C++
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BEA WebLogic Enterprise (Formarly BEA M3)
for Java
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VISIBROKER (*)
for Java
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Sun's Java 2 Platform 
CORBA Package
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Sun's Java 2 Platform
 RMI
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IDL Compiler idl [options] idl-filename [icf-filename]

where: 

  • options may be -i, to generate implementation files and/or  -T to generate tie class templates for the interfaces in a WLE application.
  • idl-filename represents the name of your application's OMG IDL file.
  • icf-filename is an optional parameter that represents the name of your application's Implementation Configuration File (ICF file)
 m3idltojava idl2java idltojava rmic
Admininistation and Other Utilities:
  • buildobjserver: compiles and links Server applications.     buildobjserver [-o servername] [options] [-o servername] represents the name of the server and [options] represent command line options.
  • buildobjclient: combines the client stubs for interfaces that use static invocation and associated header files with M3 libraries to form client executables.
  • genicf  moduleName.idl : generates moduleName.icf file used for???
  • tmloadcf: Creates the TUXCONFIG file, a binary file for the WebLogic Enterprise Domain.
  • tmboot: Used to boot-up the Enterprise Domain  and/or part of the domain. 
  • tmadmin: Used to administer the Enterprise Domain.
  • buildjavaserver : Creates a JAR file containing your Java server class  files; also creates a server descriptor file (SER). 
  • buildXAJS: For applications that use an XA-compliant resource  manager, creates an XA-specific version of the Java Server. 
  • For  building java client applications, include m3envobj.jar file in CLASSPATH. m3envobj.jar contains Java classes for M3 environmental objects.
  • tmloadcf:  Creates the TUXCONFIG file, a binary file for the WebLogic
  • Enterprise domain specifies the configuration of your server application.
  • tmadmin: Used to administer the Enterprise Domain. 
OSAgent: Smart Agent that perfoms the work of registry.
vbj: Used to start up the servers and clints.		 javac: java compiler
tnameserv:starts the name server.
java : to start the java VM.		 rmic: rmi compiler
registry: Starts a registry server
Output from IDL Compiler
  • Client stub file: application_c.cpp: Contains generated code for sending a request. 
  • Client stub header file: application_c.h: Contains class definitions for each interface and type specified in the  OMG IDL file. 
  • Skeleton file: application_s.cpp: Contains skeletons for each interface specified in the OMG IDL  file. The skeleton maps client requests to the appropriate operation in the server application during run time.
  •  Skeleton header file: application_s.h:  Contains the skeleton class definitions. 
  • Implementation file: application_i.cpp:  Contains signatures for the methods that implement the operations on the interfaces specified in the OMG IDL file. 
  • Implementation header file: application_i.h: Contains the initial class definitions for each interface specified  in the OMG IDL file. 
    Further steps:
    • Edit your object implementation files, adding the business logic to each object's methods. 
    • Create the Server object, which is code that performs the initialize and release functions for the server application.
    • Use the buildobjserver/ buildobjclent utilities to compile the server / client aplications into executables. (See sample codes showing the process flow of a server and client.) 
  • Base interface class file:   interface.java:  Contains an implementation of the interface, written in  Java. You need to copy this file to create a new file and add your business logic to the new file. By convention name this file interfaceImpl.java, substituting the actual name of the interface in the file name. 
  • Client stub file:  _interfaceStub.java: Contains generated code for sending a request. 
  • Server skeleton file:  _interfaceImplBase.java: Contains Java skeletons for each interface specified in  the OMG IDL file. The skeleton maps client requests to  the appropriate operation in the Java server application during run time. 
  • Holder class file:  interfaceHolder.java: Contains the implementation of the Holder class. The Holder class provides operations for out and inout arguments, which CORBA has, but which do not map exactly to Java. 
  • Helper class file:  interfaceHelper.java: Contains the implementation of the Helper class. The Helper class provides auxiliary functionality, notably the  narrow method. 
Further steps:
  • Edit your object implementation files, adding the business logic to each object's methods. 
  • Create the Server object, which is code that performs the initialize and release functions for the server application.
  • Use the javac compiler to compile all the *.java files into Java bytecodes (*.class files). 
  • Client stub file: interface.java:
  • Client implementation file: _InterfaceImplBase.java 
  • Server skeleton file: _st_interface.java
  • Server implementation file: _interfaceImplBase.java
  • Helper classes: interfaceHelper.java: containing utilities
  • Holder classes: interfaceHolder.java: Provids a holder for passing parameters.
  • Tie Classes: _tie_interface.java: A tie class is used to tie up an existing java class, with an interface that is CORBA compliant. 
  •  _InterfaceNameImplBase.java : This abstract class is the server skeleton, providing basic CORBA functionality for the server. It implements the InterfaceName.java interface. The server class InterfaceNameServant extends _InterfaceNameImplBase. 
  • _InterfaceNameStub.java : This class is the client stub, providing CORBA functionality for the client. It implements the InterfaceName.java interface. 
  • InerfaceName.java :  This interface contains the Java version of our IDL interface. It contains the single method doSomething(). The InterfaceName.java interface extends org.omg.CORBA.Object, providing standard CORBA object functionality as well. 
  • InterfaceNameHelper.java : This final class provides auxiliary functionality, notably the narrow() method required to cast CORBA object references to their proper types. 
  • InterfaceNameHolder.java : This final class holds a public instance member of type Hello. It provides operations for out and inout arguments, which CORBA has but which do not map easily to Java's semantics. 
  (TBD) 
Application Server Startup Procedure
  1. Prepare ubbconfig file. The ubbfile of M3 has the same structure that is used for Tuxedo UBBCONFIG File, without services section and with interface section. 
  2. Compile UBBCONFIG File using tmloadcf
  3. Start up all servers using tmboot
  1. Create a text file called a Server Description File, which is expressed in the XML language. 
  2. In your Server Description File, you assign the activation and transaction policies for the interfaces  implemented in your server application. This XML file also contains a server declaration, which includes the  name of the Server object and the name of the server descriptor file (SER). You can also identify the Java class files that comprise the server application's Java Archive (JAR) file. 
  3. Compile the XML-based Server Description File with the buildjavaserver command and generate the SER file and JAR file. 
  4. Deploy your Java server application. 
  1. Start Smart Agent using OSAgent
  2. Start Server using vbj Server
  3. Start Client using vbj Client
  1. Start Name Server using : tnameserv -ORBInitialPort 8080
  2. Start Server using : java someServer -ORBInitialPort 8080
  3. Run Client application using : java aClient -ORBInitialPort 8080
(TBD)
IDL File Contents
( Modules attributes and Interfaces)		 module ModuleName 
{
       attribute Long  aLong;

      interface InterfaceName
     {
               float operationName();
      };
};

Module is mapped to Namespace
Interface is mapped to class
Operation is mapped to member function

 module ModuleName 
{
     attribute Short nShort;

      interface InterfaceName
     {
               float operationName();
      };
};

Module is mapped to package
Interface is mapped to class
Operation is mapped to method of the class.

 module ModuleName
{
      attribute Short nShort;

     interface InterfaceName
    {
               float operationName();
      };
};

Module is mapped to package
Interface is mapped to class
Operation is mapped to method of the class.

 module ModuleName
{
     attribute Long aLong;

    interface InterfaceName
    {
        string doSomething();
    };
};

Module is mapped to package
Interface is mapped to class
Operation is mapped to method of the class.

 RMI is not CORBA  Compliant, but has the similar architecture that of Corba Product like registry and name service. Here the communication is between java applications only.
 
ORB Initialisation (TBD) orb = org.omg.CORBA.ORB.init(args, null) orb = org.omg.CORBA.ORB.init(args, null) orb = org.omg.CORBA.ORB.init(args, null) (TBD)
Locate Business Object Reference (TBD) manager = Bank.AccountManagerHelper.bind(orb,"BankManger") manager = Bank.AccountManagerHelper.bind(orb,"BankManger") (TBD) (TBD)
Class Hierarchy (TBD) (TBD) class org.omg.CORRBA.protable.Skeleton
(provided with VisiBroker)
abstract class Back._AccountManagerImplBase
(generated by idl2java)
interface bank.AccountManager
(generated by idl2java)
class AccountManagerImpl
(written by programmer and used by server)		 (TBD) (TBD)
Typical Structure of a Server Application Server has 3 major functions as follows:

CORBA::Boolean  Server::initialize(int argc, char** argv) 
{
     // Create and register factories 
     University::RegistrarFactory s_v_fact_ref =
          TP::create_object_reference(
              University::_tc_RegistrarFactory->id(),
              object_id,
              CORBA::NVList::_nil()
          );
      TP::register_factory (CORBA::Object_ptr factory_or,
                           const char* factory_id);
      // OR ???
      //TP::register_factory(s_v_fact_ref.in(),
      //                         University::_tc_RegistrarFactory->id());

     // Allocate any machine resources 

     //Initialize global variables needed by the server application 

     //Open databases used by server application 

     //Open XA resource manager 

}

Tobj_Servant  Server::create_servant(const char* interfaceName) 
{
     /// ????
      if (!strcmp(intf_repos_id, University::_tc_RegistrarFactory->id())) {
           return new RegistrarFactory_i();
       }
       if (!strcmp(intf_repos_id, University::_tc_Registrar->id())) {
           return new Registrar_i();
       }
       if (!strcmp(intf_repos_id, University::_tc_CourseSynopsisEnumerator->id())) {
           return new CourseSynopsisEnumerator_i();
       }
       return 0; // unknown interface
     }

void Server::release() 
{
      // Perform any application-specific cleanup task
      // Unregister object factories 
     TP::unregister_factory (CORBA::Object_ptr factory_or,
                                         const char* factory_id)
      // OR ???
      //TP::unregister_factory(s_v_fact_ref.in(),
      // UnivB::_tc_RegistrarFactory -> id());
      // Deallocating resources 
      // Close databases 
      // Close XA resource manager 
}

 (TBD) // Server.java
public class Server {
    public statc void main(String[] args)  {
          // Initialize the ORB.
         org.omg.CORBA.ORB orb = org.omg.CORBA.ORB.init(args, null);
         // Initialize the Basic Object Adapter (BOA).
         org.omg.CORBA.BOA boa = orb.BOA.init();
         // Create the account manager object.
         Bank.AccountManager manager = new AccountManagerImpl("Dallas");
         // Export the newly created object.
        boa.obj_is_ready(manager);
        System.out.println(manager + " is ready!");
        // Wait for incoming requests
       boa.impl_is_ready();
    }
}		 // Server.java 
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;

public class Server {
    public static void main(String args[])
    {
        try{
           // create and initialize the ORB
            ORB orb = ORB.init(args, null);

           // create servant and register it with the ORB
            HelloServant helloRef = new HelloServant();
           orb.connect(helloRef);

           // get the root naming context
            org.omg.CORBA.Object objRef = 
           orb.resolve_initial_references("NameService");

            // Narrow the reference using the helper class
            NamingContext ncRef = NamingContextHelper.narrow(objRef);

           // Bind the Object Reference in Naming
           // Note: rebind() needs array of Namecomponents.
            NameComponent nc = new NameComponent("Hello", "");
            NameComponent path[] = {nc};
           ncRef.rebind(path, helloRef);

            // wait for invocations from clients
            java.lang.Object sync = new java.lang.Object();
           synchronized (sync) {
                sync.wait();
            }

        } catch (Exception e) {
            System.err.println("ERROR: " + e);
            e.printStackTrace(System.out);
        }
    }
} 

 (TBD
Implemeting Transaction  Management???:  1. Generate ICF File using:
    genicf university.idl
    This generates the file university.icf. 

2. Edit the ICF file generated:
module POA_UniversityB
{
        implementation CourseSynopsisEnumerator_i
        {
              activation_policy ( method );
             transaction_policy ( optional );
              implements ( UniversityB::CourseSynopsisEnumerator );
        };
};

3. You can limit the number of interfaces for which you want skeleton and implementation files generated, you can remove from the ICF file the implementation blocks that implement those interfaces.

 4.Pass the ICF file to the IDL compiler to generate the skeleton and implementation files that correspond to the specified policies. 

Step 5: Compile and link the server application.

 (TBD) (TBD) (TBD) (TBD
Typical Structure of a Client Application   

    // Initialize the ORB
    CORBA::ORB_var orb_ptr = CORBA::ORB_init(argc, argv, ORBid);

    // Create a Bootstrap object to establish communication
    // with the WLE domain (Note: List of IIOP Listener/Handlers
    // can also be specified in TOBJADDR environmental variable)
    Tobj_Bootstrap* bootstrap = new Tobj_Bootstrap(orb_ptr,
                                                                                                "//host:port");

     //Get a FactoryFinder object, use it to find a  Moderator factory,
     // and get a Moderator.
     //Use the Bootstrap object to find the FactoryFinder object
     CORBA::Object_var       var_factory_finder_oref  =
    bootstrap-> resolve_initial_references ("FactoryFinder");

    // Use the factory finder to get a factory
    var_factory_finder_oref  = var_factory_finder_oref .find_one_factory_by_id(ModuleName::_tc_InterfaceName::id);
 
     //Narrow the FactoryFinder object
     Tobj::FactoryFinder_var        var_factory_finder_ref  =
      Tobj :: FactoryFinder :: _narrow ( var_factory_finder_oref.in());

     //Use the FactoryFinder object to find a  factory for the Moderator
     CORBA::Object_var     var_moderator_factory_oref =
     var_factory_finder->find_one_factory_by_id("ModeratorFactory" );

     //Narrow the Moderator Factory
     ChatRoom::ModeratorFactory_var     var_moderator_factory =
 ChatRoom::ModeratorFactory::_narrow(var_moderator_factory_oref.in()); 

     //Get a Moderator
     //The chatroom name is passed as a command line parameter
     var_moderator_oref =  var_moderator_factory->get_moderator
                                               (var_chat_room_name.in() ); 

  // Initialize the ORB
 org.omg.CORBA::ORB orb = org.omg.CORBA.ORB.init(args, props);

// Create a Bootstrap object to establish communication
     // with the WLE domain
     Tobj_Bootstrap bootstrap = new Tobj_Bootstrap(orb_ptr, "//host:port");
 

//Resolve Factory Finder
org.omg.CORBA.Object off = bootstrap.resolve_initial_references("FactoryFinder");
 
 

// Use the factory finder to get a factory
org.omg.CORBA.Object of  =  FactoryFinder. find_one_factory_by_id(ModuleName::_tc_InterfaceName::id);
 

 //Narrow the object
ModuleName.InerfaceName iobj = ModuleName.InterfaceName. narrow ( var_factory_finder_oref.in());
 

 // Client.java
public class Client 
{
    public statc void main(String[] args) 
   {
          // Initialize the ORB.
         org.omg.CORBA.ORB orb =
                                          org.omg.CORBA.ORB.init(args, null);

         // Locate an account manager.
         Bank.AccountManager manager =
                   Bank.AccountManagerHelper.bind(orb, "Dallas");

        // Export the newly created object.
        boa.obj_is_ready(manager);
        System.out.println(manager + " is ready!");

        // Wait for incoming requests
        boa.impl_is_ready();
    }
}

 // HelloClient.java

import HelloApp.*;
import org.omg.CosNaming.*;
import org.omg.CORBA.*;

public class HelloClient 
{
    public static void main(String args[])
    {
        try
       {
           // create and initialize the ORB
            ORB orb = ORB.init(args, null);

           // get the naming context called "NameService"
            org.omg.CORBA.Object objRef =
                                      orb.resolve_initial_references("NameService");
            NamingContext ncRef = NamingContextHelper.narrow(objRef);

           // Resolve the Object Reference 
            NameComponent nc = new NameComponent("Hello", "");
            NameComponent path[] = {nc};
            // Use resolve() to retrieve an object bound to a name in given
            //context. 
            Hello helloRef = HelloHelper.narrow(ncRef.resolve(path));

           // call the Hello server object and print results
            String hello = helloRef.sayHello();
            System.out.println(hello);
         }
        catch (Exception e) 
        {
             System.out.println("ERROR : " + e) ;
             e.printStackTrace(System.out);
        }
    }
}

 (TBD

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