Event-driven Messaging
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Event-driven Messaging
The event-driven messaging is a design pattern, applied within the service-orientation design paradigm to enable the service consumers, which are interested in events that occur within the periphery of a service provider, to get notifications about these events as and when they occur without resorting to the traditional inefficient polling based mechanism.Wajid Khattak, Vijay NarayanaEvent-Driven MessagingOnline].Date accessed: 27 April 2010. Rationale The interaction between a service consumer and a service provider is normally initiated by the service consumer as it needs to respond to an event that occurs within the boundary of the service consumer itself e.g. requiring some data from an external resource (i.e. the service provider) in order to perform a calculation whose results need to be relayed back to a user interface in response to an action performed by the user. However, there are situations where the service consumer needs to wait for the occurrence of an event wit ...
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Design Pattern
A design pattern is the re-usable form of a solution to a design problem. The idea was introduced by the architect Christopher Alexander and has been adapted for various other disciplines, particularly software engineering. The " Gang of Four" book. Details An organized collection of design patterns that relate to a particular field is called a pattern language. This language gives a common terminology for discussing the situations designers are faced with. Documenting a pattern requires explaining why a particular situation causes problems, and how the components of the pattern relate to each other to give the solution. Christopher Alexander describes common design problems as arising from "conflicting forces"—such as the conflict between wanting a room to be sunny and wanting it not to overheat on summer afternoons. A pattern would not tell the designer how many windows to put in the room; instead, it would propose a set of values to guide the designer toward a decisi ...
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Service-orientation
Service-orientation is a design paradigm for computer software in the form of services. The principles of service-oriented design stress the separation of concerns in the software. Applying service-orientation results in units of software partitioned into discrete, autonomous, and network-accessible units, each designed to solve an individual concern. These units qualify as services. History of service-orientation principles and tenets Service-orientation has received a lot of attention since 2003 due to the benefits it promises. These include increased return on investment, organisational agility and interoperability as well as a better alignment between business and IT. It builds heavily on earlier design paradigms and enhances them with standardisation, loose coupling and business involvement. The paradigm lost momentum in 2009; since 2014, renewed interest can be observed under the Microservices moniker. In technology, different vendor SOA platforms have used different definit ...
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Design Paradigm
A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' expresses the process of developing a design. In some cases, the direct construction of an object without an explicit prior plan (such as in craftwork, some engineering, coding, and graphic design) may also be considered to be a design activity. The design usually has to satisfy certain goals and constraints; may take into account aesthetic, functional, economic, or socio-political considerations; and is expected to interact with a certain environment. Typical examples of designs include architectural and engineering drawings, circuit diagrams, sewing patterns and less tangible artefacts such as business process models. Designing People who produce designs are called ''designers''. The term 'designer' generally refers to someone who wo ...
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Polling (computer Science)
Polling, or polled operation, in computer science, refers to actively sampling the status of an external device by a client program as a synchronous activity. Polling is most often used in terms of input/output (), and is also referred to as polled or software-driven . A good example of hardware implementation is a watchdog timer. Description Polling is the process where the computer or controlling device waits for an external device to check for its readiness or state, often with low-level hardware. For example, when a printer is connected via a parallel port, the computer waits until the printer has received the next character. These processes can be as minute as only reading one bit. This is sometimes used synonymously with 'busy-wait' polling. In this situation, when an operation is required, the computer does nothing other than check the status of the device until it is ready, at which point the device is accessed. In other words, the computer waits until the device is ...
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Service Consumer
Service may refer to: Activities * Administrative service, a required part of the workload of university faculty * Civil service, the body of employees of a government * Community service, volunteer service for the benefit of a community or a punishment that may be imposed by a court * Fan service, a Japanese term referring to something which is specifically designed to entertain fans * Military service, serving in a country's armed forces * Feudal service, see Feudal land tenure in England * Public service, services carried out with the aim of providing a public good * Selfless service, a service which is performed without any expectation of result or award. Arts, entertainment, and media * ''Service'' (album), a 1983 album by Yellow Magic Orchestra * ''Service'' (film), a 2008 film * ''Service'' (play), a 1932 play by British writer Dodie Smith * Service (record label), a Swedish record label * "Service" (''The Walking Dead''), a 2016 television episode of ''The Walking ...
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Service Provider
A service provider (SP) is an organization that provides services, such as consulting, legal, real estate, communications, storage, and processing services, to other organizations. Although a service provider can be a sub-unit of the organization that it serves, it is usually a third-party or outsourcing, outsourced supplier. Examples include telecommunications service providers (TSPs), application service providers (ASPs), storage service providers (SSPs), and internet service providers (ISPs). A more traditional term is service bureau. IT professionals sometimes differentiate between service providers by categorizing them as type I, II, or III. The three service types are recognized by the IT industry although specifically defined by ITIL and the U.S. Telecommunications Act of 1996. *Type I: internal service provider *Type II: shared service provider *Type III: external service provider Type III SPs provide IT services to external customers and subsequently can be referred to as ...
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User Interface
In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, while the machine simultaneously feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls and process controls. The design considerations applicable when creating user interfaces are related to, or involve such disciplines as, ergonomics and psychology. Generally, the goal of user interface design is to produce a user interface that makes it easy, efficient, and enjoyable (user-friendly) to operate a machine in the way which produces the desired result (i.e. maximum usability). This generally means that the operator needs to provide minimal input ...
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SOA DP Event-Driven Messaging A
Soa may refer to: Places Scotland *Soa (near Coll), an island in the United Kingdom in Argyll and Bute *Soa, Tiree, a tidal island of Tiree, Argyll and Bute *Soa Island, an islet lying south of Iona, Argyll and Bute, Scotland Elsewhere *Soa (Phrygia), a town of ancient Phrygia, now in Turkey *Soa, Cameroon, a town in Centre region *Soa Airport, in Bajawa, Indonesia *Søo, a river in Norway, also known as the Søa Other uses * ''Soa'' (barklice), a genus in the family Lepidopsocidae *Soa Palelei (born 1977), Australian mixed martial artist *Soa de Muse, French drag queen See also * SOA (other) * SOAS (other) SOAS or Soas or ''variation'', may refer to: * 427 Special Operations Aviation Squadron, Canadian Special Operations Forces Command, Royal Canadian Air Force, Canadian Armed Forces, Canada * Oracle SOA Suite, a middleware product for service-orien ...
* {{Disambiguation, geo ...
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SOA DP Event-Driven Messaging B
Soa may refer to: Places Scotland *Soa (near Coll), an island in the United Kingdom in Argyll and Bute *Soa, Tiree, a tidal island of Tiree, Argyll and Bute *Soa Island, an islet lying south of Iona, Argyll and Bute, Scotland Elsewhere *Soa (Phrygia), a town of ancient Phrygia, now in Turkey *Soa, Cameroon, a town in Centre region *Soa Airport, in Bajawa, Indonesia *Søo, a river in Norway, also known as the Søa Other uses * ''Soa'' (barklice), a genus in the family Lepidopsocidae *Soa Palelei (born 1977), Australian mixed martial artist *Soa de Muse, French drag queen See also * SOA (other) * SOAS (other) SOAS or Soas or ''variation'', may refer to: * 427 Special Operations Aviation Squadron, Canadian Special Operations Forces Command, Royal Canadian Air Force, Canadian Armed Forces, Canada * Oracle SOA Suite, a middleware product for service-orien ...
* {{Disambiguation, geo ...
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Observer Pattern
In software design and engineering, the observer pattern is a software design pattern in which an object, named the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes, usually by calling one of their methods. It is often used for implementing distributed event-handling systems in event-driven software. In such systems, the subject is usually named a "stream of events" or "stream source of events" while the observers are called "sinks of events." The stream nomenclature alludes to a physical setup in which the observers are physically separated and have no control over the emitted events from the subject/stream source. This pattern thus suits any process by which data arrives from some input that is not available to the CPU at startup, but instead arrives seemingly at random (HTTP requests, GPIO data, user input from peripherals, distributed databases and blockchain A blockchain is a type of distributed ledg ...
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Object-oriented Design
Object-oriented design (OOD) is the process of planning a system of interacting objects for the purpose of solving a software problem. It is one approach to software design. Overview An object contains encapsulated data and procedures grouped together to represent an entity. The 'object interface' defines how the object can be interacted with. An object-oriented program is described by the interaction of these objects. Object-oriented design is the discipline of defining the objects and their interactions to solve a problem that was identified and documented during object-oriented analysis. What follows is a description of the class-based subset of object-oriented design, which does not include object prototype-based approaches where objects are not typically obtained by instantiating classes but by cloning other (prototype) objects. Object-oriented design is a method of design encompassing the process of object-oriented decomposition and a notation for depicting both logical ...
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