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    Corba Unit 4

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    roshnibiju
    CORBA allows distributed objects written in different languages to communicate. It defines an Interface Definition Language (IDL) to describe object interfaces without specifying the implementation. An Object Request Broker (ORB) mediates communication between client objects and server objects, using stubs and skeletons. The ORB is also responsible for object registration and lookup via naming services, and communication between ORBs uses the Internet Inter-ORB Protocol.

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    Corba Unit 4

    Uploaded by

    roshnibiju
    17 views4 pages
    CORBA allows distributed objects written in different languages to communicate. It defines an Interface Definition Language (IDL) to describe object interfaces without specifying the implementation. An Object Request Broker (ORB) mediates communication between client objects and server objects, using stubs and skeletons. The ORB is also responsible for object registration and lookup via naming services, and communication between ORBs uses the Internet Inter-ORB Protocol.

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    CORBA allows distributed objects written in different languages to communicate. It defines an Interface Definition Language (IDL) to describe object interfaces without specifying the implementation. An Object Request Broker (ORB) mediates communication between client objects and server objects, using stubs and skeletons. The ORB is also responsible for object registration and lookup via naming services, and communication between ORBs uses the Internet Inter-ORB Protocol.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    17 views4 pages

    Corba Unit 4

    Uploaded by

    roshnibiju
    CORBA allows distributed objects written in different languages to communicate. It defines an Interface Definition Language (IDL) to describe object interfaces without specifying the implementation. An Object Request Broker (ORB) mediates communication between client objects and server objects, using stubs and skeletons. The ORB is also responsible for object registration and lookup via naming services, and communication between ORBs uses the Internet Inter-ORB Protocol.

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    of 4

    CORBA-UNIT 4

    I-CORBA (Common Object Request Broker Architecture)

     Common Object Request Broker Architecture.


     CORBA is a standard defined by OMG(Object Management Group)
     It describes architecture, interfaces and protocols that distributed objects
    can use to interact with each other.
     Very important part of CORBA is the IDL(Interface Definition
    Language),which is an implementation-independent language for
    describing the interface of remote objects.
     OMG defines standard mapping for converting IDL interface to C++,C
    and java
     Java IDL is Sun’s implementation of the standard IDL to java mapping.
     CORBA is included in the packages,
    1)org.omg.CORBA
    2)org.omg.COSNaming
    3)org.omg.*;

    II- Difference between RMI and CORBA

    RMI CORBA
    RMI is a Java-specific technology CORBA has implementation for
    many languages
    It uses Java interface for It uses Interface Definition Language
    implementation. (IDL) to separate interface from
    implementation
    RMI objects are garbage collected CORBA objects are not garbage
    automatically. collected because it is language
    independent and some languages like
    C++ does not support garbage
    collection.

    RMI programs can download new CORBA does not this code sharing
    classes from remote JVM’s. mechanism

    RMI passes objects by remote CORBA passes objects by reference.


    reference or by value
    Java RMI is a server-centric model CORBA is a peer-to-peer system.

    RMI uses the Java Remote CORBA use Internet Inter- ORB
    Method Protocol as its underlying Protocol as its underlying remoting
    remoting protocol. protocol.
    III-Architecute of CORBA

    The CORBA architecture for distributed objects shares many features with the
    architecture used by java RMI.A description of a remote object is used to
    generate a client stub interface and server skeleton interface for the object. A
    client application invokes methods on a remote object using the client stub,
    whereas the server skeleton for the object is asked to invoke the method on the
    object itself
    The majorcomponents of the CORBA architecture include IDL,ORB and
    object Adapter, Naming services and Inter-ORB communication protocol.
     IDL defines the CORBA interfaces.
     ORB and object adapter are responsible for handling all interaction
    between remote object and application that use them.
     Naming services provides remote client to find remote object on the
    network.
     The Inter-ORB protocols handle the low-level communication between
    processes in a CORBA context.

    IV-IDL(Interface Definition Language)

     IDL provides the primary way of describing data types in CORBA.


     IDL is a declaration language.
     In IDL we can declare only the name and type of interface, datamembers,
    method etc.
     IDL is implemented of any particular programming language
     Mapping or binding from IDL to specific language are defined and
    standardized as part of the CORBA specification.
     Standard binding for c, c++, ada, COBOL,LISP,python and java have
    been approved by the OMG.
     The central CORBA functions, services, facilities and services are
    specified in IDL.

    V-The Object Request Brocker and Object Adapter

    The core of the CORBA architecture is the ORB.Each machine involved


    in a CORBA application must have an ORB.This is for,ORB running for
    process on that machine to interact with CORBA object running in remote
    process.Client and server make request through their ORBs.ORB is responsible
    for making the request happen or indicating why the cannot.The client ORB
    provides a stub for a remote objects.Request made on the stub are passed to the
    implementation through an object adapter and the object skeleton interface.
    The Object adapter provides a general facility that plugs a server object
    into a particular CORBA runtime environment. All server objects can use the
    object adapter to interact with the core functionality of ORB and the ORB in
    turn use the object adapter to pas along client request and life cycle notification
    to the server.

    VI-Namingservices of CORBA(COSNaming-Corba Object Service


    Naming)

    The CORBA naming services provides a naming structure for remote objects.
    The CORBA naming services is one of the naming and directory services
    provided by JNDI.
    The naming tree always starts with a root node,and sub nodes of the object tree
    can be created by an application.
    Actual objects are stored by name at the leaves of the tree
    Eg:
    The full name of the object labeled Fred is -living things,animal,man,fred in that
    order.

    Living things

    animals

    man ox

    fred
     Each branch in the directory tree is called naming context.
     Each node in the names directory is represented by an
    org.omg.COSNaming.NamingContext object.
     We can get a reference to the root content by using
    resolve_initial_refernce() method.
     Once we can have the reference we can perform lookups of CORBA
    object,as well as register your own corba objects with the naming
    services.

    VII-Inter ORB communication

     The CORBA standard includes specification for inter ORB


    communication protocol.It is used to transmit object requests
    between various ORB’s running on the network.
     The protocols are independent of the particular ORB running on
    either ends of the communication links.that is an ORB implement
    in java can take to another ORB implement in C.
     The inter ORB protocol is responsible for delivering messages
    between two cooperating ORBs.These messages might be method
    request,return type or error message.
     The inter ORB protocol also deals with difference between the two
    ORB implementation(machine level and alignment)
     The internet Inter ORB protocol(IIOP) is an inter ORB protocol on
    TCP/IP.

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