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Dependency (computer Science)
In software engineering, coupling is the degree of interdependence between software modules; a measure of how closely connected two routines or modules are; the strength of the relationships between modules. Coupling is usually contrasted with cohesion. Low coupling often correlates with high cohesion, and vice versa. Low coupling is often thought to be a sign of a well-structured computer system and a good design, and when combined with high cohesion, supports the general goals of high readability and maintainability. History The software quality metrics of coupling and cohesion were invented by Larry Constantine in the late 1960s as part of a structured design, based on characteristics of “good” programming practices that reduced maintenance and modification costs. Structured design, including cohesion and coupling, were published in the article ''Stevens, Myers & Constantine'' (1974) and the book ''Yourdon & Constantine'' (1979), and the latter subsequently became stan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Engineering
Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term '' programmer'' is sometimes used as a synonym, but may also lack connotations of engineering education or skills. Engineering techniques are used to inform the software development process which involves the definition, implementation, assessment, measurement, management, change, and improvement of the software life cycle process itself. It heavily uses software configuration management which is about systematically controlling changes to the configuration, and maintaining the integrity and traceability of the configuration and code throughout the system life cycle. Modern processes use software versioning. History Beginning in the 1960s, software engineering was seen as its own type of engineering. Additionally, the development of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SOAP
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are used as thickeners, components of some lubricants, and precursors to catalysts. When used for cleaning, soap solubilizes particles and grime, which can then be separated from the article being cleaned. In hand washing, as a surfactant, when lathered with a little water, soap kills microorganisms by disorganizing their membrane lipid bilayer and denaturing their proteins. It also emulsifies oils, enabling them to be carried away by running water. Soap is created by mixing fats and oils with a base. A similar process is used for making detergent which is also created by combining chemical compounds in a mixer. Humans have used soap for millennia. Evidence exists for the production of soap-like materials in ancient Babylon around 2800 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Make (software)
In software development, Make is a build automation tool that automatically builds executable programs and libraries from source code by reading files called ''Makefiles'' which specify how to derive the target program. Though integrated development environments and language-specific compiler features can also be used to manage a build process, Make remains widely used, especially in Unix and Unix-like operating systems. Besides building programs, Make can be used to manage any project where some files must be updated automatically from others whenever the others change. Origin There are now a number of dependency-tracking build utilities, but Make is one of the most widespread, primarily due to its inclusion in Unix, starting with the PWB/UNIX 1.0, which featured a variety of tools targeting software development tasks. It was originally created by Stuart Feldman in April 1976 at Bell Labs. Feldman received the 2003 ACM Software System Award for the authoring of this widespr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Object-oriented Programming Terms
This is a list of terms found in object-oriented programming. Some are related to object-oriented programming and some are not. A *Abstract class *Accessibility * Abstract method *Abstraction (computer science) *Access control *Access modifiers *Accessor method *Adapter pattern * Aspect-oriented B *Bridge pattern * Builder pattern *Base class C *Cast *Chain-of-responsibility pattern *Class *Class hierarchy *Class method * Class object *Class variable * Cohesion * Collection class *Composition * Constructor *Container (abstract data type) * Contravariance *Copy constructor *Coupling *Covariance D * Data-driven design * Data hiding *Default constructor * Deep copy *Delegation * Dependency injection * Destructor * Dispatch table *Dynamic binding, also called Late binding * Dynamic dispatch * Dynamically typed language E *Early binding * Eigenclass *Encapsulation (computer programming) *European Conference on Object-Oriented Programming *Exception handling *Extension F * Facad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inversion Of Control
In software engineering, inversion of control (IoC) is a design pattern in which custom-written portions of a computer program receive the flow of control from a generic framework. A software architecture with this design inverts control as compared to traditional procedural programming: in traditional programming, the custom code that expresses the purpose of the program calls into reusable libraries to take care of generic tasks, but with inversion of control, it is the framework that calls into the custom, or task-specific, code. Inversion of control is used to increase modularity of the program and make it extensible, and has applications in object-oriented programming and other programming paradigms. The term was used by Michael Mattsson in a thesis, taken from there by Stefano Mazzocchi and popularized by him in 1999 in a defunct Apache Software Foundation project, Avalon, then further popularized in 2004 by Robert C. Martin and Martin Fowler. The term is related to, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Efferent Coupling
Efferent coupling is a coupling metric in software development. It measures the number of data types a class knows about. This includes inheritance, interface implementation, parameter types, variable types, and exceptions. This has also been referred to by Robert C. Martin as the Fan-out stability metric which in his book Clean Architecture he describes as Outgoing dependencies. This metric identifies the number of classes inside this component that depend on classes outside the component. This metric is often used to calculate instability of a component in software architecture Software architecture is the fundamental structure of a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements and relations. ... as ''I'' = Fan-out / (Fan-in + Fan-out). This metric has a range ,1 ''I'' = 0 is maximally stable while ''I'' = 1 is maximally unstable. References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependency Hell
Dependency hell is a colloquial term for the frustration of some software users who have installed software packages which have dependencies on specific versions of other software packages. The dependency issue arises when several packages have dependencies on the same ''shared'' packages or libraries, but they depend on different and incompatible versions of the shared packages. If the shared package or library can only be installed in a single version, the user may need to address the problem by obtaining newer or older versions of the dependent packages. This, in turn, may break other dependencies and push the problem to another set of packages. Problems Dependency hell takes several forms: ; Many dependencies : An application depends on many libraries, requiring lengthy downloads, large amounts of disk space, and being very portable (all libraries are already ported enabling the application itself to be ported easily). It can also be difficult to locate all the dependencie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dead Code Elimination
In compiler theory, dead-code elimination (also known as DCE, dead-code removal, dead-code stripping, or dead-code strip) is a compiler optimization to remove code which does not affect the program results. Removing such code has several benefits: it shrinks program size, an important consideration in some contexts, and it allows the running program to avoid executing irrelevant operations, which reduces its running time. It can also enable further optimizations by simplifying program structure. ''Dead code'' includes code that can never be executed (''unreachable code''), and code that only affects '' dead variables'' (written to, but never read again), that is, irrelevant to the program. Examples Consider the following example written in C. int foo(void) Simple analysis of the uses of values would show that the value of b after the first assignment is not used inside foo. Furthermore, b is declared as a local variable inside foo, so its value cannot be used outside foo. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coupling (physics)
In physics, two objects are said to be coupled when they are interacting with each other. In classical mechanics, coupling is a connection between two oscillating systems, such as pendulums connected by a spring. The connection affects the oscillatory pattern of both objects. In particle physics, two particles are coupled if they are connected by one of the four fundamental forces. Wave mechanics Coupled harmonic oscillator If two waves are able to transmit energy to each other, then these waves are said to be "coupled." This normally occurs when the waves share a common component. An example of this is two pendulums connected by a spring. If the pendulums are identical, then their equations of motion are given by m\ddot = -mg\frac - k(x-y) m\ddot = -mg \frac + k(x-y) These equations represent the simple harmonic motion of the pendulum with an added coupling factor of the spring. This behavior is also seen in certain molecules (such as CO2 and H2O), wherein two of the atom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connascence (computer Science)
Connascence () is a software quality metric invented by Meilir Page-Jones to allow reasoning about the complexity caused by dependency relationships in object-oriented design much like coupling did for structured design. In software engineering, two components are connascent if a change in one would require the other to be modified in order to maintain the overall correctness of the system. In addition to allowing categorization of dependency relationships, connascence also provides a system for comparing different types of dependency. Such comparisons between potential designs can often hint at ways to improve the quality of the software. Strength A form of connascence is considered to be stronger if it is more likely to require compensating changes in connascent elements. The stronger the form of connascence, the more difficult and costly it is to change the elements in the relationship. Degree The acceptability of connascence is related to the degree of its occurrence. Con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cohesion (computer Science)
In computer programming, cohesion refers to the ''degree to which the elements inside a module belong together''. In one sense, it is a measure of the strength of relationship between the methods and data of a class and some unifying purpose or concept served by that class. In another sense, it is a measure of the strength of relationship between the class's methods and data themselves. Cohesion is an ordinal type of measurement and is usually described as “high cohesion” or “low cohesion”. Modules with high cohesion tend to be preferable, because high cohesion is associated with several desirable traits of software including robustness, reliability, reusability, and understandability. In contrast, low cohesion is associated with undesirable traits such as being difficult to maintain, test, reuse, or even understand. Cohesion is often contrasted with coupling, a different concept. High cohesion often correlates with loose coupling, and vice versa. The software metrics of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
