Chapter 20 corba fm
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Soft computing Lab Mannual, Distributed systems
| • An interface definition language known as IDL, which is illustrated early in Section 20.2 and described more fully in Section 20.2.3. • An architecture, which is discussed in Section 20.2.2. • The GIOP defines an external data representation, called CDR, which is described in Section 4.3. It also defines specific formats for the messages in a request-reply protocol. In addition to request and reply messages, it specifies messages for enquiring about the location of an object, for cancelling requests and for reporting errors. • The IIOP, an implementation of GIOP defines a standard form for remote object references, which is described in Section The CORBA architecture also allows for CORBA services – a set of generic services that can be useful for distributed applications. These are introduced in Section which includes a more detailed discussion of the Naming Service, the Event Service, the Notification Service and the Security Service. For an interesting collection of articles on CORBA, seethe CACM special issue [Seetharamanan 1998]. SECTION 20.2 CORBA RMI 829 Before discussing the above components of CORBA, we introduce CORBA RMI from a programmer’s point of view CORBA RMI Programming in a multi-language RMI system such as CORBA RMI requires more of the programmer than programming in a single-language RMI system such as Java RMI. The following new concepts need to be learned: • the object model offered by CORBA; • the interface definition language and its mapping onto the implementation language. Other aspects of CORBA programming are similar to those discussed in Chapter 5. In particular, the programmer defines remote interfaces for the remote objects and then uses an interface compiler to produce the corresponding proxies and skeletons. But in CORBA, proxies are generated in the client language and skeletons in the server language. We will use the shared whiteboard example introduced in Section 5.5 to illustrate how to write an IDL specification and to build server and client programs. Download 234.39 Kb. Share with your friends:
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