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The Common Object Request Broker Architecture (CORBA) is a
standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object th ...
defined by the
Object Management Group The Object Management Group (OMG) is a computer industry standards consortium. OMG Task Forces develop enterprise integration standards for a range of technologies. Business activities The goal of the OMG was a common portable and interoperab ...
(OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between systems on different operating systems,
programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...
s, and computing hardware. CORBA uses an object-oriented model although the systems that use the CORBA do not have to be object-oriented. CORBA is an example of the
distributed object In distributed computing, distributed objects are objects (in the sense of object-oriented programming) that are distributed across different address spaces, either in different processes on the same computer, or even in multiple computers conn ...
paradigm.


Overview

CORBA enables communication between software written in different languages and running on different computers. Implementation details from specific operating systems, programming languages, and hardware platforms are all removed from the responsibility of developers who use CORBA. CORBA normalizes the method-call semantics between application objects residing either in the same address-space (application) or in remote address-spaces (same host, or remote host on a network). Version 1.0 was released in October 1991. CORBA uses an
interface definition language interface description language or interface definition language (IDL), is a generic term for a language that lets a program or object written in one language communicate with another program written in an unknown language. IDLs describe an inter ...
(IDL) to specify the interfaces that objects present to the outer world. CORBA then specifies a ''mapping'' from IDL to a specific implementation language like
C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...
or
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...
. Standard mappings exist for
Ada Ada may refer to: Places Africa * Ada Foah, a town in Ghana * Ada (Ghana parliament constituency) * Ada, Osun, a town in Nigeria Asia * Ada, Urmia, a village in West Azerbaijan Province, Iran * Ada, Karaman, a village in Karaman Province, ...
, C,
C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...
,
C++11 C++11 is a version of the ISO/ IEC 14882 standard for the C++ programming language. C++11 replaced the prior version of the C++ standard, called C++03, and was later replaced by C++14. The name follows the tradition of naming language versions b ...
, COBOL,
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...
, Lisp,
PL/I PL/I (Programming Language One, pronounced and sometimes written PL/1) is a procedural, imperative computer programming language developed and published by IBM. It is designed for scientific, engineering, business and system programming. I ...
,
Object Pascal Object Pascal is an extension to the programming language Pascal that provides object-oriented programming (OOP) features such as classes and methods. The language was originally developed by Apple Computer as ''Clascal'' for the Lisa Worksh ...
,
Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...
,
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called ...
and Smalltalk. Non-standard mappings exist for C#, Erlang,
Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offic ...
,
Tcl TCL or Tcl or TCLs may refer to: Business * TCL Technology, a Chinese consumer electronics and appliance company **TCL Electronics, a subsidiary of TCL Technology * Texas Collegiate League, a collegiate baseball league * Trade Centre Limited ...
and
Visual Basic Visual Basic is a name for a family of programming languages from Microsoft. It may refer to: * Visual Basic .NET (now simply referred to as "Visual Basic"), the current version of Visual Basic launched in 2002 which runs on .NET * Visual Basic ( ...
implemented by
object request broker In distributed computing, an object request broker (ORB) is a middleware which allows program calls to be made from one computer to another via a computer network, providing location transparency through remote procedure calls. ORBs promote interop ...
s (ORBs) written for those languages. The CORBA specification dictates there shall be an ORB through which an application would interact with other objects. This is how it is implemented in practice: # The application initializes the ORB, and accesses an internal ''Object Adapter'', which maintains things like reference counting, object (and reference) instantiation policies, and object lifetime policies. # The Object Adapter is used to register instances of the ''generated code classes''. Generated code classes are the result of compiling the user IDL code, which translates the high-level interface definition into an OS- and language-specific class base for use by the user application. This step is necessary in order to enforce CORBA semantics and provide a clean user process for interfacing with the CORBA infrastructure. Some IDL mappings are more difficult to use than others. For example, due to the nature of Java, the IDL-Java mapping is rather straightforward and makes usage of CORBA very simple in a Java application. This is also true of the IDL to Python mapping. The C++ mapping requires the programmer to learn datatypes that predate the C++
Standard Template Library The Standard Template Library (STL) is a software library originally designed by Alexander Stepanov for the C++ programming language that influenced many parts of the C++ Standard Library. It provides four components called ''algorithms'', '' ...
(STL). By contrast, the C++11 mapping is easier to use, but requires heavy use of the STL. Since the C language is not object-oriented, the IDL to C mapping requires a C programmer to manually emulate object-oriented features. In order to build a system that uses or implements a CORBA-based distributed object interface, a developer must either obtain or write the IDL code that defines the object-oriented interface to the logic the system will use or implement. Typically, an ORB implementation includes a tool called an IDL compiler that translates the IDL interface into the target language for use in that part of the system. A traditional compiler then compiles the generated code to create the linkable-object files for use in the application. This diagram illustrates how the generated code is used within the CORBA infrastructure: This figure illustrates the high-level paradigm for remote interprocess communications using CORBA. The CORBA specification further addresses data typing, exceptions, network protocols, communication timeouts, etc. For example: Normally the server side has the
Portable Object Adapter The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between sy ...
(POA) that redirects calls either to the local
servants A domestic worker or domestic servant is a person who works within the scope of a residence. The term "domestic service" applies to the equivalent occupational category. In traditional English contexts, such a person was said to be "in service ...
or (to balance the load) to the other servers. The CORBA specification (and thus this figure) leaves various aspects of distributed system to the application to define including object lifetimes (although reference counting semantics are available to applications), redundancy/fail-over, memory management, dynamic load balancing, and application-oriented models such as the separation between display/data/control semantics (e.g. see Model–view–controller), etc. In addition to providing users with a language and a platform-neutral
remote procedure call In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure ( subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal ( ...
(RPC) specification, CORBA defines commonly needed services such as transactions and security, events, time, and other domain-specific interface models.


Versions history

This table presents the history of CORBA standard versions.


Servants

A servant is the invocation target containing methods for handling the
remote method invocation In a distributed computing environment, distributed object communication realizes communication between distributed objects. The main role is to allow objects to access data and invoke methods on remote objects (objects residing in non-local memor ...
s. In the newer CORBA versions, the remote object (on the server side) is split into the object ''(that is exposed to remote invocations)'' and servant ''(to which the former part forwards the method calls)''. It can be one ''servant'' per remote ''object'', or the same servant can support several (possibly all) objects, associated with the given
Portable Object Adapter The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between sy ...
. The ''servant'' for each ''object'' can be set or found "once and forever" (servant activation) or dynamically chosen each time the method on that object is invoked (servant location). Both servant locator and servant activator can forward the calls to another server. In total, this system provides a very powerful means to balance the load, distributing requests between several machines. In the object-oriented languages, both remote ''object'' and its ''servant'' are objects from the viewpoint of the object-oriented programming. ''Incarnation'' is the act of associating a servant with a CORBA object so that it may service requests. Incarnation provides a concrete servant form for the virtual CORBA object. Activation and deactivation refer only to CORBA objects, while the terms incarnation and etherealization refer to servants. However, the lifetimes of objects and servants are independent. You always incarnate a servant before calling activate_object(), but the reverse is also possible, create_reference() activates an object without incarnating a servant, and servant incarnation is later done on demand with a Servant Manager. The ' (POA) is the CORBA object responsible for splitting the server side remote invocation handler into the remote ''object'' and its ''servant''. The object is exposed for the remote invocations, while the servant contains the methods that are actually handling the requests. The servant for each object can be chosen either statically (once) or dynamically (for each remote invocation), in both cases allowing the call forwarding to another server. On the server side, the POAs form a tree-like structure, where each POA is responsible for one or more objects being served. The branches of this tree can be independently activated/deactivated, have the different code for the servant location or activation and the different request handling policies.


Features

The following describes some of the most significant ways that CORBA can be used to facilitate communication among distributed objects.


Objects By Reference

This reference is either acquired through a stringified
Uniform Resource Locator A Uniform Resource Locator (URL), colloquially termed as a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifi ...
(URL), NameService lookup (similar to
Domain Name System The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned t ...
(DNS)), or passed-in as a method parameter during a call. Object references are lightweight objects matching the interface of the real object (remote or local). Method calls on the reference result in subsequent calls to the ORB and blocking on the thread while waiting for a reply, success or failure. The parameters, return data (if any), and exception data are marshaled internally by the ORB according to the local language and OS mapping.


Data By Value

The CORBA Interface Definition Language provides the language- and OS-neutral inter-object communication definition. CORBA Objects are passed by reference, while data (integers, doubles, structs, enums, etc.) are passed by value. The combination of Objects-by-reference and data-by-value provides the means to enforce great data typing while compiling clients and servers, yet preserve the flexibility inherent in the CORBA problem-space.


Objects By Value (OBV)

Apart from remote objects, the CORBA and
RMI-IIOP RMI-IIOP (read as "RMI over IIOP") denotes the Java Remote Method Invocation (RMI) interface over the Internet Inter-Orb Protocol (IIOP), which delivers Common Object Request Broker Architecture (CORBA) distributed computing A distributed syst ...
define the concept of the OBV and Valuetypes. The code inside the methods of Valuetype objects is executed locally by default. If the OBV has been received from the remote side, the needed code must be either ''
a priori ("from the earlier") and ("from the later") are Latin phrases used in philosophy to distinguish types of knowledge, justification, or argument by their reliance on empirical evidence or experience. knowledge is independent from current ...
'' known for both sides or dynamically downloaded from the sender. To make this possible, the record, defining OBV, contains the Code Base that is a space-separated list of URLs whence this code should be downloaded. The OBV can also have the remote methods.


CORBA Component Model (CCM)

CORBA Component Model (CCM) is an addition to the family of CORBA definitions. It was introduced with CORBA 3 and it describes a standard application framework for CORBA components. Though not dependent on "language dependent
Enterprise Java Beans Jakarta Enterprise Beans (EJB; formerly Enterprise JavaBeans) is one of several Java APIs for modular construction of enterprise software. EJB is a server-side software component that encapsulates business logic of an application. An EJB web c ...
(EJB)", it is a more general form of EJB, providing four component types instead of the two that EJB defines. It provides an abstraction of entities that can provide and accept services through well-defined named interfaces called ''ports''. The CCM has a component container, where software components can be deployed. The container offers a set of services that the components can use. These services include (but are not limited to) notification,
authentication Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicatin ...
, persistence and
transaction processing Transaction processing is information processing in computer science that is divided into individual, indivisible operations called ''transactions''. Each transaction must succeed or fail as a complete unit; it can never be only partially compl ...
. These are the most-used services any distributed system requires, and, by moving the implementation of these services from the software components to the component container, the complexity of the components is dramatically reduced.


Portable interceptors

Portable interceptors are the "hooks", used by CORBA and
RMI-IIOP RMI-IIOP (read as "RMI over IIOP") denotes the Java Remote Method Invocation (RMI) interface over the Internet Inter-Orb Protocol (IIOP), which delivers Common Object Request Broker Architecture (CORBA) distributed computing A distributed syst ...
to mediate the most important functions of the CORBA system. The CORBA standard defines the following types of interceptors: #
IOR The abbreviation IOR may refer to: * Importer of record, term in import and export * inclusive or - as opposed to XOR (exclusive OR) * Independent Order of Rechabites * Index of refraction * India Office Records * Indian Ocean Region * Indian Ocea ...
interceptors mediate the creation of the new references to the remote objects, presented by the current server. # Client interceptors usually mediate the remote method calls on the client (caller) side. If the object Servant exists on the same server where the method is invoked, they also mediate the local calls. # Server interceptors mediate the handling of the remote method calls on the server (handler) side. The interceptors can attach the specific information to the messages being sent and IORs being created. This information can be later read by the corresponding interceptor on the remote side. Interceptors can also throw forwarding exceptions, redirecting request to another target.


General InterORB Protocol (GIOP)

The GIOP is an abstract protocol by which
Object request broker In distributed computing, an object request broker (ORB) is a middleware which allows program calls to be made from one computer to another via a computer network, providing location transparency through remote procedure calls. ORBs promote interop ...
s (ORBs) communicate. Standards associated with the protocol are maintained by the
Object Management Group The Object Management Group (OMG) is a computer industry standards consortium. OMG Task Forces develop enterprise integration standards for a range of technologies. Business activities The goal of the OMG was a common portable and interoperab ...
(OMG). The GIOP architecture provides several concrete protocols, including: # Internet InterORB Protocol (IIOP) – The Internet Inter-Orb Protocol is an implementation of the GIOP for use over the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
, and provides a mapping between GIOP messages and the
TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...
layer. # SSL InterORB Protocol (SSLIOP) – SSLIOP is IIOP over SSL, providing
encryption In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can de ...
and
authentication Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicatin ...
. # HyperText InterORB Protocol (HTIOP) – HTIOP is IIOP over
HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...
, providing transparent proxy bypassing. # Zipped IOP (ZIOP) – A zipped version of GIOP that reduces the bandwidth usage.


VMCID (Vendor Minor Codeset ID)

Each standard CORBA exception includes a minor code to designate the subcategory of the exception. Minor exception codes are of type unsigned long and consist of a 20-bit "Vendor Minor Codeset ID" (VMCID), which occupies the high order 20 bits, and the minor code proper which occupies the low order 12 bits. Minor codes for the standard exceptions are prefaced by the VMCID assigned to OMG, defined as the unsigned long constant CORBA::OMGVMCID, which has the VMCID allocated to OMG occupying the high order 20 bits. The minor exception codes associated with the standard exceptions that are found in Table 3–13 on page 3-58 are or-ed with OMGVMCID to get the minor code value that is returned in the ex_body structure (see Section 3.17.1, "Standard Exception Definitions", on page 3-52 and Section 3.17.2, "Standard Minor Exception Codes", on page 3-58). Within a vendor assigned space, the assignment of values to minor codes is left to the vendor. Vendors may request allocation of VMCIDs by sending email to tagrequest@omg.org. A list of currently assigned VMCIDs can be found on the OMG website at: http://www.omg.org/cgi-bin/doc?vendor-tags The VMCID 0 and 0xfffff are reserved for experimental use. The VMCID OMGVMCID (Section 3.17.1, "Standard Exception Definitions", on page 3-52) and 1 through 0xf are reserved for OMG use.
The Common Object Request Broker: Architecture and Specification (CORBA 2.3)


Corba Location (CorbaLoc)

Corba Location (CorbaLoc) refers to a stringified object reference for a CORBA object that looks similar to a URL. All CORBA products must support two OMG-defined URLs: "" and "". The purpose of these is to provide a human readable and editable way to specify a location where an IOR can be obtained. An example of corbaloc is shown below: : A CORBA product may optionally support the "", "" and "" formats. The semantics of these is that they provide details of how to download a stringified IOR (or, recursively, download another URL that will eventually provide a stringified IOR). Some ORBs do deliver additional formats which are proprietary for that ORB.


Benefits

CORBA's benefits include language- and OS-independence, freedom from technology-linked implementations, strong data-typing, high level of tunability, and freedom from the details of distributed data transfers. ; Language independence:CORBA was designed to free engineers from limitations of coupling their designs to a particular software language. Currently there are many languages supported by various CORBA providers, the most popular being Java and C++. There are also C++11, C-only, Smalltalk, Perl, Ada, Ruby, and Python implementations, just to mention a few. ; OS-independence: CORBA's design is meant to be OS-independent. CORBA is available in Java (OS-independent), as well as natively for Linux/Unix, Windows, Solaris, OS X, OpenVMS, HPUX, Android, LynxOS, VxWorks, ThreadX, INTEGRITY, and others. ; Freedom from technologies: One of the main implicit benefits is that CORBA provides a neutral playing field for engineers to be able to normalize the interfaces between various new and legacy systems. When integrating C, C++, Object Pascal, Java, Fortran, Python, and any other language or OS into a single cohesive system design model, CORBA provides the means to level the field and allow disparate teams to develop systems and unit tests that can later be joined together into a whole system. This does not rule out the need for basic system engineering decisions, such as threading, timing, object lifetime, etc. These issues are part of any system regardless of technology. CORBA allows system elements to be normalized into a single cohesive system model.
For example, the design of a
multitier architecture In software engineering, multitier architecture (often referred to as ''n''-tier architecture) is a client–server architecture in which presentation, application processing and data management functions are physically separated. The most wide ...
is made simple using
Java Servlet A Jakarta Servlet (formerly Java Servlet) is a Java software component that extends the capabilities of a server. Although servlets can respond to many types of requests, they most commonly implement web containers for hosting web applicati ...
s in the web server and various CORBA servers containing the business logic and wrapping the database accesses. This allows the implementations of the business logic to change, while the interface changes would need to be handled as in any other technology. For example, a database wrapped by a server can have its database schema change for the sake of improved disk usage or performance (or even whole-scale database vendor change), without affecting the external interfaces. At the same time, C++ legacy code can talk to C/Fortran legacy code and Java database code, and can provide data to a web interface. ; Data-typing: CORBA provides flexible data typing, for example an "ANY" datatype. CORBA also enforces tightly coupled datatyping, reducing human errors. In a situation where Name-Value pairs are passed around, it is conceivable that a server provides a number where a string was expected. CORBA Interface Definition Language provides the mechanism to ensure that user-code conforms to method-names, return-, parameter-types, and exceptions. ; High tunability: Many implementations (e.g. ORBexpress (Ada, C++, and Java implementation) and OmniORB (open source C++ and Python implementation)) have options for tuning the threading and connection management features. Not all ORB implementations provide the same features. ; Freedom from data-transfer details: When handling low-level connection and threading, CORBA provides a high level of detail in error conditions. This is defined in the CORBA-defined standard exception set and the implementation-specific extended exception set. Through the exceptions, the application can determine if a call failed for reasons such as "Small problem, so try again", "The server is dead" or "The reference does not make sense." The general rule is: Not receiving an exception means that the method call completed successfully. This is a very powerful design feature. ; Compression: CORBA marshals its data in a binary form and supports compression. IONA, Remedy IT, and
Telefónica Telefónica, S.A. () is a Spanish multinational telecommunications company headquartered in Madrid, Spain. It is one of the largest telephone operators and mobile network providers in the world. It provides fixed and mobile telephony, broadba ...
have worked on an extension to the CORBA standard that delivers compression. This extension is called ZIOP and this is now a formal OMG standard.


Problems and criticism

While CORBA delivered much in the way code was written and software constructed, it has been the subject of criticism. Much of the criticism of CORBA stems from poor implementations of the standard and not deficiencies of the standard itself. Some of the failures of the standard itself were due to the process by which the CORBA specification was created and the compromises inherent in the politics and business of writing a common standard sourced by many competing implementors. ;Initial implementation incompatibilities :The initial specifications of CORBA defined only the IDL, not the on-the-wire format. This meant that source-code compatibility was the best that was available for several years. With CORBA 2 and later this issue was resolved. ;Location transparency :CORBA's notion of location transparency has been criticized; that is, that objects residing in the same address space and accessible with a simple
function call In computer programming, a function or subroutine is a sequence of program instructions that performs a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed. Functions may ...
are treated the same as objects residing elsewhere (different processes on the same machine, or different machines). This is a fundamental design flaw, as it makes all object access as complex as the most complex case (i.e., remote network call with a wide class of failures that are not possible in local calls). It also hides the inescapable differences between the two classes, making it impossible for applications to select an appropriate use strategy (that is, a call with 1
µs A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available. A microsecond is equal to 1 ...
latency and guaranteed return will be used very differently from a call with 1s latency with possible transport failure, in which the delivery status is potentially unknown and might take 30s to time out). ;Design and process deficiencies :The creation of the CORBA standard is also often cited for its process of
design by committee Design by committee is a pejorative term for a project that has many designers involved but no unifying plan or vision. Usage of the term The term is used to refer to suboptimal traits that such a process may produce as a result of having to compr ...
. There was no process to arbitrate between conflicting proposals or to decide on the hierarchy of problems to tackle. Thus the standard was created by taking a union of the features in all proposals with no regard to their coherence. This made the specification complex, expensive to implement entirely, and often ambiguous. :A design committee composed of a mixture of implementation vendors and customers created a diverse set of interests. This diversity made difficult a cohesive standard. Standards and interoperability increased competition and eased customers' movement between alternative implementations. This led to much political fighting within the committee and frequent releases of revisions of the CORBA standard that some ORB implementors ensured were difficult to use without proprietary extensions. Less ethical CORBA vendors encouraged customer lock-in and achieved strong short-term results. Over time the ORB vendors that encourage portability took over market share. ;Problems with implementations :Through its history, CORBA has been plagued by shortcomings in poor ORB implementations. Unfortunately many of the papers criticizing CORBA as a standard are simply criticisms of a particularly bad CORBA ORB implementation. :CORBA is a comprehensive standard with many features. Few implementations attempt to implement all of the specifications, and initial implementations were incomplete or inadequate. As there were no requirements to provide a reference implementation, members were free to propose features which were never tested for usefulness or implementability. Implementations were further hindered by the general tendency of the standard to be verbose, and the common practice of compromising by adopting the sum of all submitted proposals, which often created APIs that were incoherent and difficult to use, even if the individual proposals were perfectly reasonable. :Robust implementations of CORBA have been very difficult to acquire in the past, but are now much easier to find. The SUN Java SDK comes with CORBA built-in. Some poorly designed implementations have been found to be complex, slow, incompatible and incomplete. Robust commercial versions began to appear but for significant cost. As good quality free implementations became available the bad commercial implementations died quickly. ;Firewalls :CORBA (more precisely, GIOP) is not tied to any particular communications transport. A specialization of GIOP is the Internet Inter-ORB Protocol or IIOP. IIOP uses raw
TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...
connections in order to transmit data. :If the client is behind a very restrictive firewall or
transparent proxy In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. Instead of connecting directly to a server that can fulfill a request ...
server environment that only allows
HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...
connections to the outside through port 80, communication may be impossible, unless the proxy server in question allows the HTTP CONNECT method or
SOCKS A sock is a piece of clothing worn on the feet and often covering the ankle or some part of the calf. Some types of shoes or boots are typically worn over socks. In ancient times, socks were made from leather or matted animal hair. In the late ...
connections as well. At one time, it was difficult even to force implementations to use a single standard port – they tended to pick multiple random ports instead. As of today, current ORBs do have these deficiencies. Due to such difficulties, some users have made increasing use of web services instead of CORBA. These communicate using
XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable ...
/
SOAP Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are use ...
via port 80, which is normally left open or filtered through a HTTP proxy inside the organization, for web browsing via HTTP. Recent CORBA implementations, though, support SSL and can be easily configured to work on a single port. Some ORBS, such as
TAO ''Tao'' or ''Dao'' is the natural order of the universe, whose character one's intuition must discern to realize the potential for individual wisdom, as conceived in the context of East Asian philosophy, East Asian religions, or any other phil ...
, omniORB and JacORB also support bidirectional GIOP, which gives CORBA the advantage of being able to use callback communication rather than the polling approach characteristic of web service implementations. Also, most modern firewalls support GIOP & IIOP and are thus CORBA-friendly firewalls.


See also


Software engineering

* Component-based software engineering *
Distributed computing A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...
* Portable object *
Service-oriented architecture In software engineering, service-oriented architecture (SOA) is an architectural style that focuses on discrete services instead of a monolithic design. By consequence, it is also applied in the field of software design where services are provide ...
(SOA)


Component-based software technologies

*
Freedesktop.org freedesktop.org (fd.o) is a project to work on interoperability and shared base technology for free-software desktop environments for the X Window System (X11) and Wayland on Linux and other Unix-like operating systems. It was founded by Hav ...
D-Bus In computing, D-Bus (short for "Desktop Bus") is a message-oriented middleware mechanism that allows communication between multiple processes running concurrently on the same machine. D-Bus was developed as part of the freedesktop.org project, ...
– current open cross-language cross-platform object model * GNOME Bonobo – deprecated GNOME cross-language object model *
KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-known products include the ...
DCOP – deprecated KDE interprocess and software componentry communication system *
KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-known products include the ...
KParts KDE Frameworks is a collection of libraries and software frameworks readily available to any Qt-based software stacks or applications on multiple operating systems. Featuring frequently needed functionality solutions like hardware integration, fi ...
– KDE component framework * Component Object Model (COM) – Microsoft Windows-only cross-language object model * DCOM (Distributed COM) – extension making COM able to work in networks * Common Language Infrastructure – Current .NET cross-language cross-platform object model *
XPCOM Cross Platform Component Object Model (XPCOM) is a cross-platform component model from Mozilla. It is similar to Microsoft Component Object Model (COM) and Common Object Request Broker Architecture (CORBA). It features multiple language bindings ...
(Cross Platform Component Object Model) – developed by Mozilla for applications based on it (e.g.
Mozilla Application Suite The Mozilla Application Suite (originally known as Mozilla, marketed as the Mozilla Suite) is a discontinued cross-platform integrated Internet suite. Its development was initiated by Netscape Communications Corporation, before their acquisition ...
,
SeaMonkey SeaMonkey is a free and open-source Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code, which itself grew out of Netscape Communicator and formed the base of Netscape 6 and Netscape ...
1.x) *
IBM System Object Model In computing, the System Object Model (SOM) is an object-oriented shared library system developed by IBM. DSOM, a distributed version based on CORBA, allowed objects on different computers to communicate. SOM defines an interface between pro ...
SOM and DSOM – component systems from IBM used in
OS/2 OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 r ...
and
AIX Aix or AIX may refer to: Computing * AIX, a line of IBM computer operating systems *An Alternate Index, for a Virtual Storage Access Method Key Sequenced Data Set * Athens Internet Exchange, a European Internet exchange point Places Belgi ...
*
Internet Communications Engine The Internet Communications Engine, or Ice, is an open-source RPC framework developed by ZeroC. It provides SDKs for C++, C#, Java, JavaScript, MATLAB, Objective-C, PHP, Python, Ruby and Swift, and can run on various operating systems, inc ...
(ICE) *
Java remote method invocation In computing, the Java Remote Method Invocation (Java RMI) is a Java API that performs remote method invocation, the object-oriented equivalent of remote procedure calls (RPC), with support for direct transfer of serialized Java classes and dis ...
(Java RMI) *
Java Platform, Enterprise Edition Jakarta EE, formerly Java Platform, Enterprise Edition (Java EE) and Java 2 Platform, Enterprise Edition (J2EE), is a set of specifications, extending Java SE with specifications for enterprise features such as distributed computing and web ser ...
(Java EE) * JavaBean *
OpenAIR {{short description, Aspect of system integration regarding artificial intelligence The core idea of Artificial Intelligence systems integration is making individual software components, such as speech synthesizers, interoperable with other componen ...
*
Remote procedure call In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure ( subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal ( ...
(RPC) *
Windows Communication Foundation The Windows Communication Foundation (WCF), previously known as Indigo, is a free and open-source runtime and a set of APIs in the .NET Framework for building connected, service-oriented applications. .NET Core 1.0, released 2016, did not sup ...
(WCF) *
Software Communications Architecture {{inline, date=May 2014 The Software Communications Architecture (SCA) is an open architecture Open architecture is a type of computer architecture or software architecture intended to make adding, upgrading, and swapping components with other ...
(SCA) – components for embedded systems, cross-language, cross-transport, cross-platform


Language bindings

*
Language binding In programming and software design, binding is an application programming interface (API) that provides glue code specifically made to allow a programming language to use a foreign library or operating system service (one that is not native to th ...
*
Foreign function interface A foreign function interface (FFI) is a mechanism by which a program written in one programming language can call routines or make use of services written in another. Naming The term comes from the specification for Common Lisp, which explicit ...
*
Calling convention In computer science, a calling convention is an implementation-level (low-level) scheme for how subroutines or functions receive parameters from their caller and how they return a result. When some code calls a function, design choices have bee ...
* Dynamic Invocation Interface *
Name mangling In compiler construction, name mangling (also called name decoration) is a technique used to solve various problems caused by the need to resolve unique names for programming entities in many modern programming languages. It provides a way of e ...
* Application programming interface - API *
Application binary interface In computer software, an application binary interface (ABI) is an interface between two binary program modules. Often, one of these modules is a library or operating system facility, and the other is a program that is being run by a user. An ...
- ABI *
Comparison of application virtual machines Application virtualization software refers to both application virtual machines and software responsible for implementing them. Application virtual machines are typically used to allow application bytecode to run portably on many different comput ...
* SWIG opensource automatic interfaces bindings generator from many languages to many languages


References


Further reading

* * * * * * * * * * * * * * * * * * * *


External links


Official OMG CORBA Components page

Unofficial CORBA Component Model page



Corba: Gone But (Hopefully) Not Forgotten

OMG XMI Specification
{{Authority control Component-based software engineering GNOME Inter-process communication ISO standards Object-oriented programming