Editing Software component

{{Short description|Modular unit of software}}

A '''software component''' is a [[Modular design|modular]] unit    of [[software]] that [[Separation of concerns|encapsulates]] specific functionality.<ref name="pandey"/> The desired characteristics of a component are [[reusability]] and [[maintainability]].<ref name="pandey">{{cite web |last1=Pandey |first1=Pankaj |date=11 July 2023 |title=Tutorial notes: Software Components and Connectors |url=https://medium.com/@publicapplicationcenter/tutorial-notes-software-components-and-connectors-a425bfd984df |website=medium.com |access-date=14 May 2024}}</ref>

==Value==

Components allow [[software development]] to assemble software with reliable parts rather than writing [[source code|code]] for every aspect; allowing for [[Systems development life cycle|implementation]] to be more like factory assembly than custom building.

==Attributes==

Desirable attributes of a component include but are not limited to:

* [[Cohesion (computer science)|Cohesive]] {{endash}} [[encapsulation (computer programming)|encapsulates]] related [[function (computer science)|functionality]] 

* [[Reusability|Reusable]]

* [[robustness (computer science)|Robust]]

* ''Substitutable'' {{endash}} can be replaced by another component with the same interface

* [[software documentation|Documented]]

* [[software testing|Tested]]

==Third-party==

Some components are built in-house by the same organization or team building the [[software system]]. Some are [[Third-party software component|third-party]], developed elsewhere and assembled into the software system.<ref>{{cite web |last1=Yadav |first1=Sunny |date=16 April 2024 |title=Types of Software Components — With Examples |url=https://www.linkedin.com/pulse/types-software-components-examples-sunny-yadav-ducaf |website=[[LinkedIn]] |access-date=14 May 2024}}</ref> 

==Component-based software engineering==

For large-scale systems, [[component-based software engineering|component-based development]] encourages a disciplined process to manage [[Programming complexity|complexity]].<ref>{{cite web |author=[[Douglas C. Schmidt]] |title=Why Software Reuse has Failed and How to Make It Work for You |url=http://www.dre.vanderbilt.edu/~schmidt/reuse-lessons.html |access-date=14 May 2024}}</ref>

==Framework==

Some components conform to a framework technology that allows them to be consumed in a well-known way. Examples include: [[Common Object Request Broker Architecture|CORBA]], [[Component Object Model|COM]], [[Enterprise JavaBeans]], and the [[.NET Framework]].<ref>{{cite journal | last1 = Crnkovic | first1 = I. | last2 = Sentilles | first2 = S. | last3 = Vulgarakis | first3 = A. | last4 = Chaudron | first4 = M. R. V. | year = 2011| title = A Classification Framework for Software Component Models | journal = IEEE Transactions on Software Engineering | volume = 37 | issue = 5| pages = 593–615 | doi = 10.1109/TSE.2010.83 | s2cid = 15449138 }}</ref><ref>{{Cite journal|last1=Lau|first1=Kung-Kiu|last2=Wang|first2=Zheng|date=2007|title=Software Component Models|journal=IEEE Transactions on Software Engineering|volume=33|issue=10|pages=709–724|doi=10.1109/TSE.2007.70726|issn=0098-5589}}</ref>

==Modeling==

[[File:Component-based-Software-Engineering-example2.png|thumb|550px|An example of interdependent components modeling a reservation system in [[Unified Modeling Language|UML]]]]

Component design is often modeled visually. In [[Unified Modeling Language]] (UML) 2.0 a component is shown as a rectangle, and an interface is shown as a lollipop to indicate a provided interface and as a socket to indicate consumption of an interface.

==History==

The idea of [[reusability|reusable]] software components was promoted by [[Douglas McIlroy]] in his presentation at the [[NATO Software Engineering Conferences|NATO Software Engineering Conference]] of 1968.<ref>{{cite web |url=http://homepages.cs.ncl.ac.uk/brian.randell/NATO/nato1968.PDF |title=Mass produced software components |first=Malcolm Douglas |last=McIlroy |work=Software Engineering: Report of a conference sponsored by the NATO Science Committee, Garmisch, Germany, 7-11 Oct. 1968 |publisher=Scientific Affairs Division, NATO |date=January 1969 |page=79}}</ref> (One goal of that conference was to resolve the so-called [[software crisis]] of the time.) In the 1970s, McIlroy put this idea into practice with the addition of the [[Pipeline (Unix)|pipeline]] feature to the [[Unix]] [[operating system]].

[[Brad Cox]] refined the concept of a software component in the 1980s.<ref>{{cite web
| access-date = 2011-07-29
| author = Rainer Niekamp
| page = 4
| publisher = Gestión de Congresos - CIMNE/Institute for Scientific Computing, TU Braunschweig
| title = Software Component Architecture
| quote = The modern concept of a software component largely defined by Brad Cox of Stepstone, => Objective-C programming language
| url = http://congress.cimne.upc.es/cfsi/frontal/doc/ppt/11.pdf
| archive-date = 2012-03-28
| archive-url = https://web.archive.org/web/20120328081234/http://congress.cimne.upc.es/cfsi/frontal/doc/ppt/11.pdf
| url-status = dead
}}</ref> He attempted to create an infrastructure and market for reusable third-party components by inventing the [[Objective-C]] programming language.<ref>{{cite book |author=[[Brad Cox]] |title=Object Oriented Programming: An Evolutionary Approach | publisher=Addison Wesley | year=1991 | isbn=0-201-54834-8}}</ref>

[[IBM]] introduced [[IBM System Object Model|System Object Model]] (SOM) in the early 1990s.<ref name=claims>{{cite web
| access-date = 2011-07-29
| author = Raphael Gfeller
| date = December 9, 2008
| page = 4
| publisher = HSR - Hochschule für Technik Rapperswill
| title = Upgrading of component-based application
| quote = 1990, IBM invents their System Object Model. 1990, as a reaction, Microsoft released OLE 1.0 OLE custom controls (OCX)
| url = http://wiki.ita.hsr.ch/SemProgAnTr/files/Automated_upgrading_of_component.Präsentation.pptx
}}{{Dead link|date=July 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

[[Microsoft]] introduced [[Component Object Model]] (COM)
in the early 1990s. Microsoft built many domain-specific component technologies on COM, including [[Distributed Component Object Model]] (DCOM), [[Object Linking and Embedding]] (OLE), and ActiveX.

==References==
{{Reflist}}

[[Category:Software architecture]]
[[Category:Software development]]
[[Category:Software engineering]]