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Delegation (programming)
In computing or computer programming, delegation refers generally to one entity passing something to another entity,Barry Wilkinson, ''Grid Computing: Techniques and Applications'' (2009), p. 164, . and narrowly to various specific forms of relationships. These include: * Delegation (object-oriented programming), evaluating a member of one object (the receiver) in the context of another, original object (the sender). ** Delegation pattern, a design pattern implementing this feature. ** Forwarding (object-oriented programming), an often-confused technique where a sending object uses the corresponding member of another object, without the receiving object having any knowledge of the original, sending object. ** Object aggregation or consultation, general term for one object using another. * Delegation (computer security), one user or process allowing another user or process to use their credentials or permissions. * Delegate (CLI), a form of type-safe function pointer used by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, engineering, mathematical, technological and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology and software engineering. The term "computing" is also synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. Computing is intimately tied to the representation of numbers, though mathematical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Programming
Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as analysis, generating algorithms, profiling algorithms' accuracy and resource consumption, and the implementation of algorithms (usually in a chosen programming language, commonly referred to as coding). The source code of a program is written in one or more languages that are intelligible to programmers, rather than machine code, which is directly executed by the central processing unit. The purpose of programming is to find a sequence of instructions that will automate the performance of a task (which can be as complex as an operating system) on a computer, often for solving a given problem. Proficient programming thus usually requires expertise in several different subjects, including knowledge of the application domain, specialized algorit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delegation (object-oriented Programming)
In object-oriented programming, delegation refers to evaluating a member (property or method) of one object (the receiver) in the context of another original object (the sender). Delegation can be done explicitly, by passing the sending object to the receiving object, which can be done in any object-oriented language; or implicitly, by the member lookup rules of the language, which requires language support for the feature. Implicit delegation is the fundamental method for behavior reuse in prototype-based programming, corresponding to inheritance in class-based programming. The best-known languages that support delegation at the language level are Self, which incorporates the notion of delegation through its notion of mutable parent slots that are used upon method lookup on self calls, and JavaScript; see JavaScript delegation. The term ''delegation'' is also used loosely for various other relationships between objects; see delegation (programming) for more. Frequently confuse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delegation Pattern
In software engineering, the delegation pattern is an object-oriented design pattern that allows object composition to achieve the same code reuse as inheritance. In delegation, an object handles a request by delegating to a second object (the ''delegate''). The delegate is a helper object, but ''with the original context''. With language-level support for delegation, this is done implicitly by having self in the delegate refer to the original (sending) object, not the delegate (receiving object). In the delegate pattern, this is instead accomplished by explicitly passing the original object to the delegate, as an argument to a method. Note that "delegation" is often used loosely to refer to the distinct concept of forwarding, where the sending object simply uses the corresponding member on the receiving object, evaluated in the context of the ''receiving'' object, not the original object. Note that this article uses "sending object/receiving object" for the two objects, rather t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forwarding (object-oriented Programming)
In object-oriented programming, forwarding means that using a member of an object (either a property or a method) results in actually using the corresponding member of a different object: the use is ''forwarded'' to another object. Forwarding is used in a number of design patterns, where some members are forwarded to another object, while others are handled by the directly used object. The forwarding object is frequently called a wrapper object, and explicit forwarding members are called wrapper functions. Delegation Forwarding is often confused with delegation; formally, they are complementary concepts. In both cases, there are two objects, and the first (sending, wrapper) object uses the second (receiving, wrappee) object, for example to call a method. They differ in what self refers to on the receiving object (formally, in the evaluation environment of the method on the receiving object): in delegation it refers to the sending object, while in forwarding it refers to the receiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Aggregation
In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kinds of compositions are objects used in object-oriented programming, tagged unions, sets, sequences, and various graph structures. Object compositions relate to, but are not the same as, data structures. Object composition refers to the logical or conceptual structure of the information, not the implementation or physical data structure used to represent it. For example, a sequence differs from a set because (among other things) the order of the composed items matters for the former but not the latter. Data structures such as arrays, linked lists, hash tables, and many others can be used to implement either of them. Perhaps confusingly, some of the same terms are used for both data structures and composites. For example, "binary tree" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delegation (computer Security)
Delegation is the process of a computer user handing over its authentication credentials to another user. In role-based access control models, delegation of authority involves delegating roles that a user can assume or the set of permissions that the user can acquire, to other users. Types of delegation in IT networks There are essentially two classes of delegation: delegation at Authentication/Identity Level, and delegation at Authorization/ Access Control Level. Delegation at Authentication/Identity level It is defined as follows: If an authentication mechanism provides an effective identity different from the validated identity of the user then it is called identity delegation at the authentication level, provided the owner of the effective identity has previously authorized the owner of the validated identity to use his identity. The existing techniques of identity delegation using sudo or su commands of UNIX are very popular. To use the sudo command, a person first has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delegate (CLI)
A delegate is a form of type-safe function pointer used by the Common Language Infrastructure (CLI). Delegates specify a method to call and optionally an object to call the method on. Delegates are used, among other things, to implement callbacks and event listeners. A delegate object encapsulates a reference to a method. The delegate object can then be passed to code that can call the referenced method, without having to know at compile time which method will be invoked. A multicast delegate is a delegate that points to several methods. Multicast delegation is a mechanism that provides functionality to execute more than one method. There is a list of delegates maintained internally, and when the multicast delegate is invoked, the list of delegates is executed. In C#, delegates are often used to implement callbacks in event driven programming. For example, a delegate may be used to indicate which method should be called when the user clicks on some button. Delegates allow the prog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Language Infrastructure
The Common Language Infrastructure (CLI) is an open specification and technical standard originally developed by Microsoft and standardized by ISO/IEC (ISO/IEC 23271) and Ecma International (ECMA 335) that describes executable code and a runtime environment that allows multiple high-level languages to be used on different computer platforms without being rewritten for specific architectures. This implies it is platform agnostic. The .NET Framework, .NET and Mono are implementations of the CLI. The metadata format is also used to specify the API definitions exposed by the Windows Runtime. Overview Among other things, the CLI specification describes the following four aspects: ;The Common Type System (CTS) :A set of data types and operations that are shared by all CTS-compliant programming languages. ;The Metadata :Information about program structure is language-agnostic, so that it can be referenced between languages and tools, making it easy to work with code wr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
