Distributed Object Computing Using Java and CORBA

1. Distributed Object Computing Using Java and CORBA

2. Lesson 1:Introduction to CORBA

3. Objectives • Describe the role of CORBA in developing enterprise applications • Describe the role of the Object Management Group • Describe the CORBA architecture

4. CORBAOverview • Common Object Request Broker Architecture • Object-oriented development • Distributed-object computing

5. The ObjectManagement Group • Controls the CORBA standard • Provides a specification for CORBA

6. CORBAArchitecture • Object Management Architecture • Object Request Broker • Object services • Common facilities • Application objects • Internet InterORB Protocol • Interface Definition Language • Object adapters • CORBA Services

7. ObjectRequest Broker

8. InternetInterORB Protocol

9. InterfaceDefinition Language

10. Summary • Describe the role of CORBA in developing enterprise applications • Describe the role of the Object Management Group • Describe the CORBA architecture

11. Lesson 2:Interface Definition Language

12. Objectives • Use the IDL to define the interface to CORBA objects • Describe the mapping of IDL nonclass data types into Java • Describe the purpose of IDL parameter-passing modes • Model inheritance using IDL • Define CORBA exceptions using IDL

13. Introduction to IDL • IDL files • IDL compilers • Mapping IDL to Java

14. Basicsof IDL • IDL constructs • Modules • Interfaces • Attributes • Operations

15. IDLPrimitives

16. Inheritance and IDL • Java  no multiple inheritance support • Java class  can inherit from only one other class • IDL  can be used to define an interface that inherits from multiple super-interfaces

17. Constants Enumerations Unions Structures Type definitions Sequences Arrays NonclassData Types

18. Parameter-PassingModes and Exceptions • Parameter-passing modes • in • out • inout • Exceptions • Use-defined exceptions inherit indirectly from java.lang.Exception • IDL operations must declare their ability to raise an exception

19. Summary • Use the IDL to define the interface to CORBA objects • Describe the mapping of IDL nonclass data types into Java • Describe the purpose of IDL parameter-passing modes • Model inheritance using IDL • Define CORBA exceptions using IDL

20. Lesson 3:Building CORBA Clients

21. Objectives • Use the IDL compiler to generate client stubs • Initialize the ORB • Use the naming service to obtain an object reference • Invoke remote methods • Use out and inout parameters to invoke remote methods

22. Client IDL Stubs • Used to create client applications • IDL-to-Java compiler named idlj • Used to compile IDL files to generate client stubs and server skeletons

23. Initializing the ORB • The ORB class • Is used to initialize the ORB • Is not instantiated using its public constructor • Provides a static method named init that initializes the ORB and returns an instance of the ORB class

24. Using theNaming Service • Connecting to the naming service • Using the naming service to obtain an object reference • Obtaining the initial naming context • Retrieving an object reference

25. Example ofNamespace

26. InvokingRemote Methods • Remote methods are invoked in the same way that local methods are invoked

27. Using Out andInout Parameters • Out parameters • Used exclusively to return data from the server to the client • Inout parameters • Passed both from the client to the server and, following any changes, from the server back to the client

28. Summary • Use the IDL compiler to generate client stubs • Initialize the ORB • Use the naming service to obtain an object reference • Invoke remote methods • Use out and inout parameters to invoke remote methods

29. Lesson 4:Building CORBA Servers

30. Objectives • Use the IDL compiler to generate server skeletons • Implement CORBA objects • Initialize the ORB and wait for clients • Use the naming service to publish an object reference • Use out and inout parameters

31. ServerIDL Skeletons • A server skeleton provides a framework for the implementation of a CORBA object

32. ImplementingCORBA Objects Server-side implementation

33. Using theNaming Service • Instantiating a CORBA object • Creating additional naming contexts

34. Example ofNaming Service

35. Waitingfor Invocation • The wait method • Called to pause the main thread of execution • Part of Java’s built-in threading facilities

36. Using Out andInout Parameters • Out parameters • Used exclusively to return data from the server to the client • Inout parameters • Passed both from the client to the server and, following any changes, from the server back to the client

37. Summary • Use the IDL compiler to generate server skeletons • Implement CORBA objects • Initialize the ORB and wait for clients • Use the naming service to publish an object reference • Use out and inout parameters

38. Lesson 5:Factory andCallback Objects

39. Objectives • Describe the purpose of factory objects • Use factory objects to obtain object references • Describe the purpose of callback objects • Develop applications that use callback objects

40. FactoryObjects • Types include: • Generic • Specific • In-process • Out-process • FactoryFinder • Using factory objects • Designing factory objects

41. CallbackObjects • Using callback objects • Designing callback objects

42. Summary • Describe the purpose of factory objects • Use factory objects to obtain object references • Describe the purpose of callback objects • Develop applications that use callback objects

43. Lesson 6:CORBA Exceptions

44. Objectives • Describe the purpose of CORBA exceptions • Define an exception using IDL • Develop CORBA objects that throw exceptions

45. Introduction to CORBA Exceptions • Throwing CORBA exceptions • Catching CORBA exceptions

46. Summary • Describe the purpose of CORBA exceptions • Define an exception using IDL • Develop CORBA objects that throw exceptions

47. Lesson 7:DynamicInvocation Interface

48. Objectives • Describe the purpose of the interface repository • Describe the Dynamic Invocation Interface • Construct an argument list for use in dynamic invocation • Invoke a request using the DII • Extract a return value following dynamic invocation

49. Dynamic InvocationInterface Introduction • DII allows a client to access any CORBA object even though it may not have a client stub to provide a compile-time definition of an object’s interface

50. Invoking a RemoteMethod Using DII • Construct a list of arguments • Prepare a place to hold a return value • Invoke the remote method • Extract the return value