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Component (UML)
A component in the Unified Modeling Language represents a modular part of a system that encapsulates the state and behavior of a number of classifiers. Its behavior is defined in terms of ''provided'' and ''required'' interfaces,OMG (2008). OMG Unified Modeling Language (OMG UML), Superstructure, V2.1.2' is self-contained, and substitutable. A number of UML standard stereotypes exist that apply to components. A component has an external and internal view, also known as "black-box" and "white-box", respectively. In its external view, there are public properties and operations. For its internal view, there are private properties and realizing classifiers and shows how external behavior is realized internally. A component may be replaced at design time or run-time by another if and only if their provided and required interfaces are identical. This idea is the underpinning for the plug-and-play capability of component-based systems and promotes software reuse. Larger pieces of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Component
Circuit Component may refer to: •Are devices that perform functions when they are connected in a circuit. In engineering, science, and technology Generic systems *System components, an entity with discrete structure, such as an assembly or software module, within a system considered at a particular level of analysis *Lumped element model, a model of spatially distributed systems Electrical *Component video, a type of analog video information that is transmitted or stored as two or more separate signals *Electronic components, the constituents of electronic circuits *Symmetrical components, in electrical engineering, analysis of unbalanced three-phase power systems Mathematics *Color model, a way of describing how colors can be represented, typically as multiple values or color components *Component (group theory), a quasi-simple subnormal sub-group *Connected component (graph theory), a maximal connected subgraph *Connected component (topology), a maximal connected su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereotype (UML)
A stereotype is one of three types of extensibility mechanisms in the Unified Modeling Language (UML), the other two being tags and constraints. They allow designers to extend the vocabulary of UML in order to create new model elements, derived from existing ones, but that have specific properties that are suitable for a particular domain or otherwise specialized usage. The nomenclature is derived from the original meaning of stereotype, used in printing. For example, when modeling a network you might need to have symbols for representing routers and hubs. By using stereotyped nodes you can make these things appear as primitive building blocks. Graphically, a stereotype is rendered as a name enclosed by guillemets (« » or, if guillemets proper are unavailable, ) and placed above the name of another element. In addition or alternatively it may be indicated by a specific icon. The icon image may even replace the entire UML symbol. For instance, in a class diagram stereotypes can b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Component Diagram
In Unified Modeling Language (UML), a component diagram depicts how components are wired together to form larger components or software systems. They are used to illustrate the structure of arbitrarily complex systems. Overview A component diagram allows verification that a system's required functionality is acceptable. These diagrams are also used as a communication tool between the developer and stakeholders of the system. Programmers and developers use the diagrams to formalize a roadmap for the implementation, allowing for better decision-making about task assignment or needed skill improvements. System administrators can use component diagrams to plan ahead, using the view of the logical software components and their relationships on the system. Diagram elements The component diagram extends the information given in a component notation element. One way of illustrating the provided and required interfaces by the specified component is in the form of a rectangular compartm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Package (UML)
A package in the Unified Modeling Language is used "to group elements, and to provide a namespace for the grouped elements". p.158. A package may contain other packages, thus providing for a hierarchical organization of packages. Pretty much all UML elements can be grouped into packages. Thus, classes, objects, s, components, nodes, node instances etc. can all be organized as packages, thus enabling a manageable organization of the myriad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Reuse
In software development (and computer programming in general), code reuse, also called software reuse, is the use of existing software, or software knowledge, to build new software, following the reusability principles. Code reuse may be achieved by different ways depending on a complexity of a programming language chosen and range from a lower-level approaches like code copy-pasting (e.g. via snippets), simple functions ( procedures or subroutines) or a bunch of objects or functions organized into modules (e.g. libraries) or custom namespaces, and packages, frameworks or software suites in higher-levels. Code reuse implies dependencies which can make code maintanability harder. At least one study found that code reuse reduces technical debt. Overview Ad hoc code reuse has been practiced from the earliest days of programming. Programmers have always reused sections of code, templates, functions, and procedures. Software reuse as a recognized area of study in software eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Component-based Software Engineering
Component-based software engineering (CBSE), also called component-based development (CBD), is a branch of software engineering that emphasizes the separation of concerns with respect to the wide-ranging functionality available throughout a given software system. It is a reuse-based approach to defining, implementing and composing loosely coupled independent components into systems. This practice aims to bring about an equally wide-ranging degree of benefits in both the short-term and the long-term for the software itself and for organizations that sponsor such software. Software engineering practitioners regard components as part of the starting platform for service-orientation. Components play this role, for example, in web services, and more recently, in service-oriented architectures (SOA), whereby a component is converted by the web service into a ''service'' and subsequently inherits further characteristics beyond that of an ordinary component. Components can produce or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plug-and-play
In computing, a plug and play (PnP) device or computer bus is one with a specification that facilitates the recognition of a hardware component in a system without the need for physical device configuration or user intervention in resolving resource conflicts. The term "plug and play" has since been expanded to a wide variety of applications to which the same lack of user setup applies. Expansion devices are controlled and exchange data with the host system through defined memory or I/O space port addresses, direct memory access channels, interrupt request lines and other mechanisms, which must be uniquely associated with a particular device to operate. Some computers provided unique combinations of these resources to each slot of a motherboard or backplane. Other designs provided all resources to all slots, and each peripheral device had its own address decoding for the registers or memory blocks it needed to communicate with the host system. Since fixed assignments made expansi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Program Lifecycle Phase
{{about, a technical topic, project management, software development process Program lifecycle phases are the stages a computer program undergoes, from initial creation to deployment and execution. The phases are edit time, compile time, link time, distribution time, installation time, load time, and run time. Lifecycle phases do not necessarily happen in a linear order, and they can be intertwined in various ways. For example, when modifying a program, software developers may need to repeatedly edit, compile, install, and execute it on their own computers to ensure sufficient quality before it can be distributed to users; copies of the modified program are then downloaded, installed, and executed by users on their computers. Phases Edit time is when the source code of the program is being edited. This spans initial creation to any bug fix, refactoring, or addition of new features. Editing is typically performed by a person, but automated design tools and metaprogramming syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Box (software Engineering)
A white box (or glass box, clear box, or open box) is a subsystem whose internals can be viewed but usually not altered.Patrick J. Driscoll, "Systems Thinking," in Gregory S. Parnell, Patrick J. Driscoll, and Dale L. Henderson (eds.), ''Decision Making in Systems Engineering and Management'', 2nd. ed., Hoboken, NJ: Wiley, 2011, 40. The term is used in systems engineering as well as in software engineering. Having access to the subsystem internals in general makes the subsystem easier to understand, but also easier to hack; for example, if a programmer can examine source code, weaknesses in an algorithm are much easier to discover. That makes white-box testing much more effective than black-box testing but considerably more difficult from the sophistication needed on the part of the tester to understand the subsystem. See also * Black box * White-box cryptography * White-box testing White-box testing (also known as clear box testing, glass box testing, transparent box tes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black-box
In science, computing, and engineering, a black box is a system which can be viewed in terms of its inputs and outputs (or transfer characteristics), without any knowledge of its internal workings. Its implementation is "opaque" (black). The term can be used to refer to many inner workings, such as those of a transistor, an engine, an algorithm, the human brain, or an institution or government. To analyse an open system with a typical "black box approach", only the behavior of the stimulus/response will be accounted for, to infer the (unknown) ''box''. The usual representation of this ''black box system'' is a data flow diagram centered in the box. The opposite of a black box is a system where the inner components or logic are available for inspection, which is most commonly referred to as a white box (sometimes also known as a "clear box" or a "glass box"). History The modern meaning of the term "black box" seems to have entered the English language around 1945. In electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substitutability
The Liskov substitution principle (LSP) is a particular definition of a subtyping relation, called strong behavioral subtyping, that was initially introduced by Barbara Liskov in a 1988 conference keynote address titled ''Data abstraction and hierarchy''. It is based on the concept of "substitutability" a principle in object-oriented programming stating that an object (such as a class) may be replaced by a sub-object (such as a class that extends the first class) without breaking the program. It is a semantic rather than merely syntactic relation, because it intends to guarantee semantic interoperability of types in a hierarchy, object types in particular. Barbara Liskov and Jeannette Wing described the principle succinctly in a 1994 paper as follows: ''Subtype Requirement'': Let be a property provable about objects of type . Then should be true for objects of type where is a subtype of . Symbolically: :S <: T \to (\forall xT) \phi(x) \to (\forall yS) \phi(y) That ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unified Modeling Language
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system. The creation of UML was originally motivated by the desire to standardize the disparate notational systems and approaches to software design. It was developed at Rational Software in 1994–1995, with further development led by them through 1996. In 1997, UML was adopted as a standard by the Object Management Group (OMG), and has been managed by this organization ever since. In 2005, UML was also published by the International Organization for Standardization (ISO) as an approved ISO standard. Since then the standard has been periodically revised to cover the latest revision of UML. In software engineering, most practitioners do not use UML, but instead produce informal hand drawn diagrams; these diagrams, however, often include elements from UML. History Before UML 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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