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Discriminator
In distributed computing, a discriminator is a typed tag field present in OMG IDL discriminated union type and value definitions that determines which union member is selected in the current union instance. Unlike in some conventional programming languages offering support for unions, discriminator in IDL is not identical to selected field name. Here is an example of IDL union type definition: union Register switch (char) ; Effective value of the ''Register'' type may contain AX as selected field, but discriminator value may be either 'a' or 'b' and it is stored in memory separately. Therefore, IDL logically separates information about currently selected field name and union effective value from information about current discriminator value. In the example above, discriminator value may be anything of the following: 'a', 'b', 'c', as well as all other characters belonging to the IDL char type, since the default branch specified in the example ''Register'' type allows use of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tagged Union
In computer science, a tagged union, also called a variant, variant record, choice type, discriminated union, disjoint union, sum type or coproduct, is a data structure used to hold a value that could take on several different, but fixed, types. Only one of the types can be in use at any one time, and a tag field explicitly indicates which one is in use. It can be thought of as a type that has several "cases", each of which should be handled correctly when that type is manipulated. This is critical in defining recursive datatypes, in which some component of a value may have the same type as the value itself, for example in defining a type for representing trees, where it is necessary to distinguish multi-node subtrees and leaves. Like ordinary unions, tagged unions can save storage by overlapping storage areas for each type, since only one is in use at a time. Description Tagged unions are most important in functional languages such as ML and Haskell, where they are called dataty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Computing
A distributed system is a system whose components are located on different computer network, networked computers, which communicate and coordinate their actions by message passing, passing messages to one another from any system. Distributed computing is a field of computer science that studies distributed systems. The components of a distributed system interact with one another in order to achieve a common goal. Three significant challenges of distributed systems are: maintaining concurrency of components, overcoming the clock synchronization, lack of a global clock, and managing the independent failure of components. When a component of one system fails, the entire system does not fail. Examples of distributed systems vary from service-oriented architecture, SOA-based systems to massively multiplayer online games to peer-to-peer, peer-to-peer applications. A computer program that runs within a distributed system is called a distributed program, and ''distributed programming' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Management Group
The Object Management Group (OMG) is a computer industry standardization, 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 interoperable object model with methods and data that work using all types of development environments on all types of platforms. The group provides only specifications, not implementations. But before a specification can be accepted as a standard by the group, the members of the submitter team must guarantee that they will bring a conforming product to market within a year. This is an attempt to prevent unimplemented (and unimplementable) standards. Other private companies or open source groups are encouraged to produce conforming products and OMG is attempting to develop mechanisms to enforce true interoperability. OMG hosts four technical meetings per year for its members and interested nonmembers. The Technical Meetings provide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interface Description 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 interface in a Language-independent specification, language-independent way, enabling communication between software components that do not share one language, for example, between those written in C++ and those written in Java (programming language), Java. IDLs are commonly used in remote procedure call software. In these cases the machines at either end of the ''link'' may be using different operating systems and computer languages. IDLs offer a bridge between the two different systems. Software systems based on IDLs include Sun Microsystems, Sun's ONC RPC, The Open Group's Distributed Computing Environment, IBM's System Object Model, the Object Management Group's CORBA (which implements OMG IDL, an IDL based on DCE/RPC) and Data Distributio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft Interface Definition Language
Microsoft Interface Definition Language (MIDL) is a text-based interface description language from Microsoft, based on the DCE/RPC DCE/RPC, short for "Distributed Computing Environment / Remote Procedure Calls", is the remote procedure call system developed for the Distributed Computing Environment (DCE). This system allows programmers to write distributed software as if it w ... IDL which it extends for use with the Microsoft Component Object Model. Its compiler is also called MIDL. See also * Object Description Language External links Microsoft Docs reference {{compu-lang-stub Microsoft development tools Component-based software engineering Microsoft application programming interfaces Object-oriented programming Object models ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Annotation
In the Java computer programming language, an annotation is a form of syntactic metadata that can be added to Java source code. Classes, methods, variables, parameters and Java packages may be annotated. Like Javadoc tags, Java annotations can be read from source files. Unlike Javadoc tags, Java annotations can also be embedded in and read from Java class files generated by the Java compiler. This allows annotations to be retained by the Java virtual machine at run-time and read via reflection. It is possible to create meta-annotations out of the existing ones in Java. History The Java platform has various ''ad-hoc'' annotation mechanisms—for example, the ''transient'' modifier, or the ''@Deprecated'' javadoc tag. The Java Specification Request JSR-175 introduced the general-purpose annotation (also known as ''metadata'') facility to the Java Community Process in 2002; it gained approval in September 2004. Annotations became available in the language itself beginning w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
