Information about Corba
The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) that enables software components written in multiple computer languages and running on multiple computers to work together.
CORBA uses an interface definition language (IDL) to specify the interfaces that objects will present to the outside world. CORBA then specifies a “mapping” from IDL to a specific implementation language like C++ or Java. Standard mappings exist for Ada, C, C++, Lisp, Smalltalk, Java, COBOL, PL/I and Python. There are also non-standard mappings for Perl, Visual Basic, Ruby, Erlang, and Tcl implemented by object request brokers (ORBs) written for those languages.
The CORBA specification dictates that there shall be an ORB through which the application interacts with other objects. In practice, the application simply initializes the ORB, and accesses an internal Object Adapter which maintains such issues as reference counting, object (& reference) instantiation policies, object lifetime policies, etc. 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 the CORBA semantics and provide a clean user processes for interfacing with the CORBA infrastructure.
Some IDL language mappings are more hostile than others. For example, due to the very nature of Java, the IDL-Java Mapping is rather trivial and makes usage of CORBA very simple in a Java application. The C++ mapping is not trivial but accounts for all the features of CORBA, i.e. exception handling. The C-mapping is even more strange (since it's not an OO language) but it does make sense and handles the RPC semantics just fine. (Red Hat Linux delivers with the GNOME UI system, which has its IPC built on CORBA)
A "language mapping" requires that the developer ("user" in this case) create some IDL code representing the interfaces to his objects. Typically a CORBA implementation (either an Open Source or commercial product) comes with a tool called an IDL compiler. This compiler will convert the user's IDL code into some language-specific generated code. The generated code is then compiled using a traditional compiler to create the linkable-object files required by 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. Issues not addressed here, but that are accounted-for in the CORBA specification include: data typing, exceptions, network protocol, communication timeouts, etc. For example: Normally the server side has the Portable Object Adapter (POA) that redirects calls either to the local servants or (to balance the load) to the other servers. Also, both server and client parts often have interceptors that are described below. Issues CORBA (and thus this figure) does not address, but that all distributed systems must address: object lifetimes, redundancy/fail-over, naming semantics (beyond a simple name), memory management, dynamic load balancing, separation of model between display/data/control semantics, etc.
In addition to providing users with a language and a platform-neutral remote procedure call specification, CORBA defines commonly needed services such as transactions and security, events, time, and other domain-specific interface models.
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 (if any) are marshaled internally by the ORB according the local language/OS mapping.
The OBV's may have fields that are transferred when the OBV is transferred. These fields can be OBV's themselves, forming lists, trees or arbitrary graphs. The OBV's have a class hierarchy, including multiple inheritance and abstract classes.
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, persistence and transaction management. 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.
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.
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.
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)
All CORBA products must support two OMG-defined URLs: "corbaloc:" and "corbaname:". The purpose of these is to provide a human readable/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 "http:", "ftp:" and "file:" 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).
For example, the design of a Multitier architecture is made simple using Java Servlets 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 (obviously 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 codes can talk to C/Fortran legacy codes and Java database codes, and can provide data to the web interface.
Also a design committee composed largely of vendors of the standard implementation creates a disincentive to a comprehensive standard, because standards and interoperability increase competition and ease customers' movement between alternative implementations. This leads to much political fighting within the committee, and frequently release of revisions of the CORBA standard that are impossible to use without proprietary extensions.[1]
Working implementations of CORBA had been very difficult to acquire in the past, but are now much easier to find. (The Java SDK comes with CORBA already.) Some poorly designed implementations had been found to be complex, slow, incompatible and incomplete. Commercial versions can be very expensive. This changed significantly as commercial-, hobbyist-, and government-funded high quality free implementations became available.
Perhaps the main reason "CORBA has fallen out of favor" was the advent of Java soon after CORBA's introduction. Of course CORBA attempted a goal of tall-order. Java was definitely able to cover the issues but only if your entire system is in Java. But this is not the case for integrating legacy systems with new system elements, or developing new high-performance C++/Fortran codes. Since Java has been the "hot item", new systems could be developed in Java alone, and thus RMI/J2EE could be used exclusively. In that case, perhaps CORBA is not necessary.
An interface description language (or alternately, interface definition language), or IDL for short, is a computer language used to describe a software component's interface.
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General overview
CORBA is a mechanism in software for normalizing the method-call semantics between application objects that reside either in the same address space (application) or remote address space (same host, or remote host on a network).CORBA uses an interface definition language (IDL) to specify the interfaces that objects will present to the outside world. CORBA then specifies a “mapping” from IDL to a specific implementation language like C++ or Java. Standard mappings exist for Ada, C, C++, Lisp, Smalltalk, Java, COBOL, PL/I and Python. There are also non-standard mappings for Perl, Visual Basic, Ruby, Erlang, and Tcl implemented by object request brokers (ORBs) written for those languages.
The CORBA specification dictates that there shall be an ORB through which the application interacts with other objects. In practice, the application simply initializes the ORB, and accesses an internal Object Adapter which maintains such issues as reference counting, object (& reference) instantiation policies, object lifetime policies, etc. 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 the CORBA semantics and provide a clean user processes for interfacing with the CORBA infrastructure.
Some IDL language mappings are more hostile than others. For example, due to the very nature of Java, the IDL-Java Mapping is rather trivial and makes usage of CORBA very simple in a Java application. The C++ mapping is not trivial but accounts for all the features of CORBA, i.e. exception handling. The C-mapping is even more strange (since it's not an OO language) but it does make sense and handles the RPC semantics just fine. (Red Hat Linux delivers with the GNOME UI system, which has its IPC built on CORBA)
A "language mapping" requires that the developer ("user" in this case) create some IDL code representing the interfaces to his objects. Typically a CORBA implementation (either an Open Source or commercial product) comes with a tool called an IDL compiler. This compiler will convert the user's IDL code into some language-specific generated code. The generated code is then compiled using a traditional compiler to create the linkable-object files required by 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. Issues not addressed here, but that are accounted-for in the CORBA specification include: data typing, exceptions, network protocol, communication timeouts, etc. For example: Normally the server side has the Portable Object Adapter (POA) that redirects calls either to the local servants or (to balance the load) to the other servers. Also, both server and client parts often have interceptors that are described below. Issues CORBA (and thus this figure) does not address, but that all distributed systems must address: object lifetimes, redundancy/fail-over, naming semantics (beyond a simple name), memory management, dynamic load balancing, separation of model between display/data/control semantics, etc.
In addition to providing users with a language and a platform-neutral remote procedure call specification, CORBA defines commonly needed services such as transactions and security, events, time, and other domain-specific interface models.
Key features
Objects By Reference
Objects are used in an application "by reference". This reference is either acquired though a "stringified" URI string, NameService lookup (similar to 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 (if any) are marshaled internally by the ORB according the local language/OS mapping.
Data By Value
The CORBA Interface Definition Language provides the language/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 strong 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 define the concept of the OBV. The code inside the methods of these objects is executed locally by default. If the OBV has been received from the remote side, the needed code must be either a priori 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 from where this code should be downloaded. The OBV can also have the remote methods.The OBV's may have fields that are transferred when the OBV is transferred. These fields can be OBV's themselves, forming lists, trees or arbitrary graphs. The OBV's have a class hierarchy, including multiple inheritance and abstract classes.
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 independent Enterprise Java Beans (EJB)", it is a more general form of EJB, providing 4 component types instead of the 2 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, persistence and transaction management. 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.
External links
- Official OMG CORBA Components page
- Unofficial CORBA Component Model page
- System Configuration
- EJCCM: Computational Physics Inc's free Java CCM implementation
Portable interceptors
Portable interceptors are the "hooks", used by CORBA and RMI-IIOP to mediate the most important functions of the CORBA system. The CORBA standard defines the following types of interceptors:- IOR 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 (CORBA) 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)
- Internet InterORB Protocol (IIOP) - The Internet Inter-Orb Protocol, is a protocol for communication between CORBA ORBs that has been published by the Object Management Group. IIOP is an implementation of the GIOP for use over an internet, and provides a mapping between GIOP messages and the TCP/IP layer.
- SSL InterORB Protocol (SSLIOP) - SSLIOP is IIOP over SSL, providing encryption and authentication.
- HyperText InterORB Protocol (HTIOP) - HTIOP is IIOP over HTTP, providing transparent proxy bypassing.
- and many more...
Data Distribution Service (DDS)
The Object Management Group (OMG) has a related standard known as the Data Distribution Service (DDS) standard. DDS is a publish-subscribe data distribution model, in contrast to the CORBA remotely-invoked object model.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 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.
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 means Corba Location and 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: "corbaloc:" and "corbaname:". The purpose of these is to provide a human readable/editable way to specify a location where an IOR can be obtained.
An example of corbaloc is shown below:
- corbaloc::160.45.110.41:38693/StandardNS/NameServer-POA/_root
A CORBA product may optionally support the "http:", "ftp:" and "file:" 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).
External links
Benefits - The Problem That CORBA Solves
CORBA brings to the table many benefits that no other single technology brings in one package. These 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 at the outset was designed to free engineers from the hang-ups and limitations of considering their designs based on a particular software language. Currently there are many languages supported by various CORBA providers, the most popular are Java and C++. There are also C-only, SmallTalk, Perl, Ada, and Python implementations, just to mention a few.OS Independence
CORBA's design is also meant to be OS-independent. CORBA is available in Java (of course also OS-independent), Linux/Unix, Windows, Sun, Mac, etc.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++, Java, Fortran, Python, and any other language/OS in to 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. Of course 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) But the main issue is to allow system elements to be normalized into a single cohesive system model.For example, the design of a Multitier architecture is made simple using Java Servlets 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 (obviously 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 codes can talk to C/Fortran legacy codes and Java database codes, and can provide data to the web interface.
Strong Data Typing
CORBA provides flexible data typing (for example an "ANY" type) but also it enforces tightly coupled data-typing, reducing human errors. In a situation where Name-Value pairs are passed around, it's 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" not only to the method-names, but also the return-, parameter-types, and exceptions.High Tune-ability
There are many implementations available (for example: OmniORB, Open source C++ and Python implementation) that have many options for tuning the threading and connection management features. Of course not all implementations have the same features. (That's not CORBA's fault, it's the implementor's responsibility)Freedom From Data Transfer Details
While handling the low-level connection and threading semantics, CORBA also provides for a high-level of detail about "when things go wrong" with a method-call. This is defined in the CORBA-defined standard exception set, and the implementation-specific extended exceptions. Through the exceptions, the application can determine whether a call failed for a "small problem, so try again" or "the server is dead", or "the reference doesn't make sense." The general rule is: "no exception means method call is guaranteed." This is a very powerful design feature.Problems and criticism
While CORBA promises to deliver much in the way code is written and software constructed, it was much criticized during its history, and some implementations have failed to deliver some of its features.[1] Some of its failures are due to the implementations and the process by which CORBA was created as a standard, others reflect problems in the politics and business of implementing a software standard. These problems, unfortunately, have led to a significant decline in CORBA use and adoption in new projects and areas, and have caused the technology to be "replaced" by Java-centric technologies. [2]Fundamental flaws
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 are treated the same as objects residing elsewhere (different processes on the same machine, or different machines). This notion is flawed if one requires that all local accesses be as complex as the most complex remote scenario. However CORBA does not place a restriction on the complexity of the calls. Many implementations provided for recursive thread/connection semantics (i.e. Obj A calls B, which then calls A back before returning the A)Design and process deficiencies
The creation of the CORBA standard is also often cited for its process of design by committee. There is no process to arbitrate between conflicting proposals, or to decide on the hierarchy of problems to tackle. Thus the standard was often created by taking a union of features in all proposals, with no regard to their coherence.[2] This made the specification very complex, prohibitively expensive (if at all possible) to implement entirely, and often ambiguous.Also a design committee composed largely of vendors of the standard implementation creates a disincentive to a comprehensive standard, because standards and interoperability increase competition and ease customers' movement between alternative implementations. This leads to much political fighting within the committee, and frequently release of revisions of the CORBA standard that are impossible to use without proprietary extensions.[1]
Problems with implementations
Through its history (like any other standards-process), CORBA was plagued by shortcomings of its implementations. Often, there were few implementations matching all of the critical elements of the specification,[2] and existing implementations were incomplete or inadequate. As there is no requirement to provide a reference implementation, members are free to propose features which were never tested for usefulness or implementability. Implementations are further hindered by the general tendency of the standard to be verbose, and the common practice of setting compromise as a sum of all submitted proposals, which often creates APIs that are incoherent, quirky or even impossible to use, even if the individual proposals were perfectly reasonable.Working implementations of CORBA had been very difficult to acquire in the past, but are now much easier to find. (The Java SDK comes with CORBA already.) Some poorly designed implementations had been found to be complex, slow, incompatible and incomplete. Commercial versions can be very expensive. This changed significantly as commercial-, hobbyist-, and government-funded high quality free implementations became available.
Perhaps the main reason "CORBA has fallen out of favor" was the advent of Java soon after CORBA's introduction. Of course CORBA attempted a goal of tall-order. Java was definitely able to cover the issues but only if your entire system is in Java. But this is not the case for integrating legacy systems with new system elements, or developing new high-performance C++/Fortran codes. Since Java has been the "hot item", new systems could be developed in Java alone, and thus RMI/J2EE could be used exclusively. In that case, perhaps CORBA is not necessary.
External Links
Notes
1. ^ Trouble with CORBA An historical essay, outlining some of the problems that eventually allowed Java's popularity to over-shadow the problem CORBA was trying to solve
2. ^ Response to the Rise and Fall of CORBA, the other side of the story
3. ^ Rise and Fall of CORBA, a comprehensive analysis of CORBA failures, by one of its former architects, Michi Henning
2. ^ Response to the Rise and Fall of CORBA, the other side of the story
3. ^ Rise and Fall of CORBA, a comprehensive analysis of CORBA failures, by one of its former architects, Michi Henning
CORBA implementations
- An overview of available CORBA implementations
- BEA Tuxedo -
- A CORBA 2.5–compliant commercial ORB for Java and C++ from BEA Systems
- Borland Enterprise Server, VisiBroker Ed. - - A CORBA 2.6–compliant commercial ORB for Java and C++ from Borland.
- Combat - A Tcl ORB, and a Tcl layer for C++ ORBs.
- ILU - An open software object interface system from Xerox PARC.
- GNU Classpath - Contains the Free Software (GPL+linking exception, including newly written org.omg packages) implementation for Java.
- IIOP.NET -
- A Free Software (LGPL) ORB for Microsoft .NET.
- JacORB - - A Free Software (LGPL) ORB implemented in Java.
- J-Integra Espresso - commercial Microsoft .NET ORB by Intrinsyc J-Integra
- MICO - - A Free Software (LGPL) ORB implemented in C++.
- omniORB -
- A Free Software (LGPL) ORB for C++ and Python.
- OpenORB - - A Free Software (BSD) ORB for Java.
- Orbacus - commercial C++ and Java ORB by IONA Technologies
- ORBexpress - standard and real-time commercial Ada, C++, and Java ORBs by Objective Interface Systems
- ORBit2 - - A Free Software (LGPL) ORB for C, C++ and Python.
- Orbix - commercial ORB by IONA Technologies
- Perl ORB -
- An open-source (Artistic License) ORB implemented in Perl.
- PolyORB - - A Free Software (MGPL) ORB implemented in Ada.
- Python ORB - - A Free Software (Python license) ORB implemented in Python.
- SANKHYA Varadhi - - A commercial ORB for C++
- TAO - - The ACE ORB, an open-source ORB for C++
- VBOrb - - A Free Software (LGPL) ORB for Visual Basic
- ORBLink - A commercial ORB for Allegro Common LISP
- R2CORBA - An open-source ORB for Ruby
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OMG trademarks
CORBA, IIOP and OMG are the registered marks of the Object Management Group and should be used with care. Differently, the GIOP is not a registered OMG trademark. Hence in some cases may be more appropriate just to say that the application uses or implements the GIOP-based architecture.See also
- Remote procedure call (RPC)
- Component technologies
- Service-oriented architecture
- Java remote method invocation
- Web service
- Distributed computing
- Servant (CORBA)
- Etherealization
- Incarnation
- Java 2 Platform, Enterprise Edition
- GNOME Bonobo
- KDE KPart
- Internet Communications Engine
- OpenAIR
References
- The official CORBA standard from the OMG group (direct download, .pdf, about 10 Mb).
- Robert Orfali: The Essential Client/Server Survival Guide, John Wiley & Sons, ISBN 0-471-15325-7
- Robert Orfali, Dan Harkey, Jeri Edwards: The Essential Distributed Objects Survival Guide, John Wiley & Sons, ISBN 0-471-12993-3
- Robert Orfali, Dan Harkey: Client/Server Programming with JAVA and CORBA, John Wiley & Sons, ISBN 0-471-24578-X
- Dirk Slama, Jason Garbis, Perry Russell: Enterprise CORBA, Prentice Hall, ISBN 0-13-083963-9
- Michi Henning, Steve Vinoski: Advanced CORBA Programming with C++, Addison-Wesley, ISBN 0-201-37927-9
- Axel Korthaus, Martin Schader, Markus Aleksy: em>Implementing Distributed Systems with Java and CORBA, Springer, ISBN 3-540-24173-6
- Fintan Bolton: Pure Corba, Sams Publishing, ISBN 0-672-31812-1
- Jon Siegel: CORBA 3 - Fundamentals and Programming, John Wiley & Sons, ISBN 0-471-29518-3
- Ron Zahavi: Enterprise Application Integration with CORBA: Component and Web-Based Solutions, John Wiley & Sons, ISBN 0-471-32720-4
- Bret Hartman, Konstantin Beznosov, Steve Vinoski, Donald Flinn: Enterprise Security with EJB and CORBA, John Wiley & Sons, ISBN 0-471-40131-5
- Thomas J. Mowbray, Ron Zahavi: The Essential Corba: System Integration Using Distributed Objects, John Wiley & Sons, ISBN 0-471-10611-9
- Michael Rosen, David Curtis: Integrating CORBA and COM Applications, John Wiley & Sons, ISBN 0-471-19827-7
- Gerald Brose, Andreas Vogel, Keith Duddy: Java Programming with CORBA, John Wiley & Sons, ISBN 0-471-37681-7
- John Schettino, Robin S. Hohman, Liz O'Hara: CORBA For Dummies, Hungry Minds, ISBN 0-7645-0308-1
- Jeremy L. Rosenberger: Teach Yourself CORBA in 14 Days, Sams Publishing, ISBN 0-672-31208-5
- Jon Siegel: Quick CORBA 3, John Wiley & Sons, ISBN 0-471-38935-8
- Thomas J. Mowbray, Raphael C. Malveau: CORBA Design Patterns, John Wiley & Sons, ISBN 0-471-15882-8
- Robert Orfali, Dan Harkey, Jeri Edwards: Instant CORBA, John Wiley & Sons, ISBN 0-471-18333-4
- Paul Harmon, William Morrissey: The Object Technology Casebook, John Wiley & Sons, ISBN 0-471-14717-6
External links
- CORBA Explained Simply
- Web Services/SOAP and CORBA
- OMG CORBA 3
- Object Management Group
- Information Board
- Catalog of OMG Specifications
- IDL / Language Mapping
- CORBA Component Model (CCM)
- IIOP
- Services
- Facilities
- Domain
- Embedded Intelligence
- Security
- UML, MOF, XMI, CWM
- Description by Christopher B. Browne
- CORBA support for autoconf
- [news://comp.object.corba discussions]
- OrbZone forum
- Article "XML as CORBA Data" by Douglas C. Schmidt and Steve Vinoski
- Article "Building Distributed Applications with Corba and XML" by Dermot Russell and Nick Simha
- SOAP Bridge
- Article "Rise and fall of CORBA" by Michi Henning
- Response to the Rise and Fall of CORBA here "http://www.orbzone.org/?p=121"
- CORBA Tutorial Links
standardization or standardisation can have several meanings depending on its context. Common use of the word standard implies that it is a universally agreed-upon set of guidelines for interoperability.
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Object Management Group (OMG) is a consortium, originally aimed at setting standards for distributed object-oriented systems, and is now focused on modeling (programs, systems and business processes) and model-based standards.
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Component-based software engineering (CBSE) (also known as Component-Based Development (CBD) or Software Componentry) is a branch of the software engineering discipline, with emphasis on decomposition of the engineered systems into functional or logical components
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A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. Programming languages, like natural languagess, are defined by syntactic and semantic rules which describe their structure and meaning respectively.
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Not to be confused with IDL (programming language).
An interface description language (or alternately, interface definition language), or IDL for short, is a computer language used to describe a software component's interface.
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C++
Paradigm: Multi-paradigm
Appeared in: 1983
Designed by: Bjarne Stroustrup
Typing discipline: Static, unsafe, nominative
Major implementations: G++, Microsoft Visual C++, Borland C++ Builder
Dialects: ISO/IEC C++ 1998, ISO/IEC C++ 2003
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Paradigm: Multi-paradigm
Appeared in: 1983
Designed by: Bjarne Stroustrup
Typing discipline: Static, unsafe, nominative
Major implementations: G++, Microsoft Visual C++, Borland C++ Builder
Dialects: ISO/IEC C++ 1998, ISO/IEC C++ 2003
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Java
Paradigm: Object-oriented, structured, imperative
Appeared in: 1995
Designed by: Sun Microsystems
Typing discipline: Static, strong, safe, nominative
Major implementations: Numerous
Influenced by: Objective-C, C++, Smalltalk, Eiffel,[1]
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Paradigm: Object-oriented, structured, imperative
Appeared in: 1995
Designed by: Sun Microsystems
Typing discipline: Static, strong, safe, nominative
Major implementations: Numerous
Influenced by: Objective-C, C++, Smalltalk, Eiffel,[1]
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Ada
Paradigm: multi-paradigm: concurrent, distributed, generic-programming, imperative, object-oriented
Appeared in: 1983, last revised 2005
Designed by: Jean Ichbiah, extended
by S.
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Paradigm: multi-paradigm: concurrent, distributed, generic-programming, imperative, object-oriented
Appeared in: 1983, last revised 2005
Designed by: Jean Ichbiah, extended
by S.
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C
The C Programming Language, Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language.
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The C Programming Language, Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language.
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C++
Paradigm: Multi-paradigm
Appeared in: 1983
Designed by: Bjarne Stroustrup
Typing discipline: Static, unsafe, nominative
Major implementations: G++, Microsoft Visual C++, Borland C++ Builder
Dialects: ISO/IEC C++ 1998, ISO/IEC C++ 2003
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Paradigm: Multi-paradigm
Appeared in: 1983
Designed by: Bjarne Stroustrup
Typing discipline: Static, unsafe, nominative
Major implementations: G++, Microsoft Visual C++, Borland C++ Builder
Dialects: ISO/IEC C++ 1998, ISO/IEC C++ 2003
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Lisp
Paradigm: multi-paradigm: functional, procedural, reflective
Appeared in: 1958
Designed by: John McCarthy
Developer: Steve Russell, Timothy P. Hart, and Mike Levin
Typing discipline: dynamic, strong
Dialects: Common Lisp, Scheme, Emacs Lisp
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Paradigm: multi-paradigm: functional, procedural, reflective
Appeared in: 1958
Designed by: John McCarthy
Developer: Steve Russell, Timothy P. Hart, and Mike Levin
Typing discipline: dynamic, strong
Dialects: Common Lisp, Scheme, Emacs Lisp
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Smalltalk
Paradigm: object-oriented
Appeared in: Development started in 1969
Publicly available in 1980
Designed by: Alan Kay, Dan Ingalls, Adele Goldberg
Developer: Alan Kay, Dan Ingalls, Adele Goldberg, Ted Kaehler, Scott Wallace, and Xerox PARC
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Paradigm: object-oriented
Appeared in: Development started in 1969
Publicly available in 1980
Designed by: Alan Kay, Dan Ingalls, Adele Goldberg
Developer: Alan Kay, Dan Ingalls, Adele Goldberg, Ted Kaehler, Scott Wallace, and Xerox PARC
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Java
Paradigm: Object-oriented, structured, imperative
Appeared in: 1995
Designed by: Sun Microsystems
Typing discipline: Static, strong, safe, nominative
Major implementations: Numerous
Influenced by: Objective-C, C++, Smalltalk, Eiffel,[1]
..... Click the link for more information.
Paradigm: Object-oriented, structured, imperative
Appeared in: 1995
Designed by: Sun Microsystems
Typing discipline: Static, strong, safe, nominative
Major implementations: Numerous
Influenced by: Objective-C, C++, Smalltalk, Eiffel,[1]
..... Click the link for more information.
COBOL
Paradigm: multi-paradigm
Appeared in: 1959
Designed by: Grace Hopper, William Selden, Gertrude Tierney, Howard Bromberg, Howard Discount, Vernon Reeves, Jean E.
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Paradigm: multi-paradigm
Appeared in: 1959
Designed by: Grace Hopper, William Selden, Gertrude Tierney, Howard Bromberg, Howard Discount, Vernon Reeves, Jean E.
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PL/I
Paradigm: imperative, structured
Appeared in: 1964
Designed by: Hursley Laboratories
Developer: IBM
Dialects: PL/M, XPL, PL/P, PL/C, PL/S, PL/AS, PL/X, PL/8, EPL
Influenced by: COBOL, Fortran, ALGOL,
PL/I
..... Click the link for more information.
Paradigm: imperative, structured
Appeared in: 1964
Designed by: Hursley Laboratories
Developer: IBM
Dialects: PL/M, XPL, PL/P, PL/C, PL/S, PL/AS, PL/X, PL/8, EPL
Influenced by: COBOL, Fortran, ALGOL,
PL/I
..... Click the link for more information.
Python
Paradigm: Multi-paradigm
Appeared in: 1991
Designed by: Guido van Rossum
Developer: Python Software Foundation
Latest release: 2.5.1/ April 18 2007
Latest unstable release: 3.
..... Click the link for more information.
Paradigm: Multi-paradigm
Appeared in: 1991
Designed by: Guido van Rossum
Developer: Python Software Foundation
Latest release: 2.5.1/ April 18 2007
Latest unstable release: 3.
..... Click the link for more information.
Perl
Paradigm: Multi-paradigm
Appeared in: 1987
Designed by: Larry Wall
Latest release: 5.8.8/ January 31 2006
Typing discipline: Dynamic
Influenced by: AWK, BASIC, BASIC-PLUS, C, C++, Lisp, Pascal, Python, sed, Unix shell
..... Click the link for more information.
Paradigm: Multi-paradigm
Appeared in: 1987
Designed by: Larry Wall
Latest release: 5.8.8/ January 31 2006
Typing discipline: Dynamic
Influenced by: AWK, BASIC, BASIC-PLUS, C, C++, Lisp, Pascal, Python, sed, Unix shell
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Visual Basic
Paradigm: Event-driven
Developer: Microsoft
Typing discipline: Static, strong
Influenced by: QuickBASIC
Influenced: Visual Basic .NET
OS: Microsoft Windows
Visual Basic (VB
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Paradigm: Event-driven
Developer: Microsoft
Typing discipline: Static, strong
Influenced by: QuickBASIC
Influenced: Visual Basic .NET
OS: Microsoft Windows
Visual Basic (VB
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Ruby
Paradigm: multi-paradigm (functional, imperative, logic, object-oriented (class-based))
Appeared in: 1995
Designed by: Yukihiro Matsumoto
Developer: Yukihiro Matsumoto (among others)
Latest release: 1.8.
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Paradigm: multi-paradigm (functional, imperative, logic, object-oriented (class-based))
Appeared in: 1995
Designed by: Yukihiro Matsumoto
Developer: Yukihiro Matsumoto (among others)
Latest release: 1.8.
..... Click the link for more information.
Erlang
Paradigm: multi-paradigm: concurrent, functional
Appeared in: 1987
Designed by: Ericsson
Developer: Ericsson
Typing discipline: dynamic, strong
Major implementations: Erlang
Influenced: Scala
License: Modified MPL
Erlang
..... Click the link for more information.
Paradigm: multi-paradigm: concurrent, functional
Appeared in: 1987
Designed by: Ericsson
Developer: Ericsson
Typing discipline: dynamic, strong
Major implementations: Erlang
Influenced: Scala
License: Modified MPL
Erlang
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TCL may mean:
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- Tcl (Tool Command Language), a computer programming language
- Terminal Control Language, used to program VeriFone devices
- Terminal Control Language, a Pick operating system command language
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In distributed computing, an object request broker (ORB) is a piece of middleware software that allows programmers to make program calls from one computer to another via a network.
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Open source is a set of principles and practices that promote access to the design and production of goods and knowledge. The term is most commonly applied to the source code of software that is available to the general public with relaxed or non-existent intellectual property
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Portable Object Adapter (POA) - The CORBA object, responsible for the 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
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Servant (CORBA) - the invocation target, containing methods for handling the remote method invocations. 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 (where the former part delegates
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Remote procedure call (RPC) is a technology that allows a computer program to cause a subroutine or procedure to execute in another address space (commonly on another computer on a shared network) without the programmer explicitly coding the details for this remote
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A priori may refer to:
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- A priori, in a legal sense, based on deduction or hypothesis. See .
- A priori (languages), a type of constructed language
- A priori (statistics), a knowledge of the actual population
- A priori (mathematical modeling)
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Uniform Resource Locator (URL) formerly known as Universal Resource Locator, is a technical, Web-related term used in two distinct meanings:
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- In popular usage, many technical documents, it is a synonym for Uniform Resource Identifier (URI);
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Enterprise Java Beans (EJB) is a managed, server-side component architecture for modular construction of enterprise applications.
The EJB specification is one of the several Java APIs in the Java Platform, Enterprise Edition.
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The EJB specification is one of the several Java APIs in the Java Platform, Enterprise Edition.
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Herod_Archelaus
