An example of two components expressed in UML 2.0. The checkout component, responsible for facilitating the customer's order, requires the card processing component to charge the customer's credit/debit card (functionality that the latter provides).

Component-based software engineering (CBSE), also called component-based development (CBD), is a style of software engineering that aims to build software out of loosely-coupled, modular components. It emphasizes the separation of concerns among different parts of a software system.

Definition and characteristics of components

An individual software component is a software package, a web service, a web resource, or a module that encapsulates a set of related functions or data.

Components communicate with each other via interfaces. Each component provides an interface (called a provided interface) through which other components can use it. When a component uses another component's interface, that interface is called a used interface.

In the UML illustrations in this article, provided interfaces are represented by lollipop-symbols, while used interfaces are represented by open socket symbols.

A simple example of several software components - pictured within a hypothetical holiday-reservation system represented in UML 2.0.

Components must be substitutable, meaning that a component must be replaceable by another one having the same interfaces without breaking the rest of the system.

Components should be reusable.

Component-based usability testing should be considered when software components directly interact with users.

Components should be:

History

The idea that software should be componentized - built from prefabricated components - first became prominent with Douglas McIlroy's address at the NATO conference on software engineering in Garmisch, Germany, 1968, titled Mass Produced Software Components.[1] The conference set out to counter the so-called software crisis. McIlroy's subsequent inclusion of pipes and filters into the Unix operating system was the first implementation of an infrastructure for this idea.

Brad Cox of Stepstone largely defined the modern concept of a software component.[2] He called them Software ICs and set out to create an infrastructure and market for these components by inventing the Objective-C programming language. (He summarizes this view in his book Object-Oriented Programming - An Evolutionary Approach 1986.)

The software components are used in two different contexts and two kinds: i) using components as parts to build a single executable, or ii) each executable is treated as a component in a distributed environment, where components collaborate with each other using internet or intranet communication protocols for IPC (Inter Process Communications). The above belongs to former kind, while the below belongs to later kind.

IBM led the path with their System Object Model (SOM) in the early 1990s. As a reaction, Microsoft paved the way for actual deployment of component software with Object linking and embedding (OLE) and Component Object Model (COM).[3] As of 2010 many successful software component models exist.

Architecture

A computer running several software components is often called an application server. This combination of application servers and software components is usually called distributed computing. Typical real-world application of this is in, e.g., financial applications or business software.

Component models

A component model is a specification of components' properties.[4]

A classification of the existing component models is given in [4] and.[5] Examples of component models are: Enterprise JavaBeans (EJB) model, Component Object Model (COM) model, .NET model, X-MAN component model,[6] and Common Object Request Broker Architecture (CORBA) component model.

Technologies

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See also

References

  1. ^ McIlroy, Malcolm Douglas (January 1969). "Mass produced software components" (PDF). Software Engineering: Report of a conference sponsored by the NATO Science Committee, Garmisch, Germany, 7-11 Oct. 1968. Scientific Affairs Division, NATO. p. 79.
  2. ^ Rainer Niekamp. "Software Component Architecture" (PDF). Gestión de Congresos - CIMNE/Institute for Scientific Computing, TU Braunschweig. p. 4. Retrieved 2011-07-29. The modern concept of a software component largely defined by Brad Cox of Stepstone, => Objective-C programming language
  3. ^ Raphael Gfeller (December 9, 2008). "Upgrading of component-based application". HSR - Hochschule für Technik Rapperswill. p. 4. Retrieved 2011-07-29. 1990, IBM invents their System Object Model. 1990, as a reaction, Microsoft released OLE 1.0 OLE custom controls (OCX)[permanent dead link]
  4. ^ a b Crnkovic, I.; Sentilles, S.; Vulgarakis, A.; Chaudron, M. R. V. (2011). "A Classification Framework for Software Component Models". IEEE Transactions on Software Engineering. 37 (5): 593–615. doi:10.1109/TSE.2010.83. S2CID 15449138.
  5. ^ Lau, Kung-Kiu; Wang, Zheng (2007). "Software Component Models". IEEE Transactions on Software Engineering. 33 (10): 709–724. doi:10.1109/TSE.2007.70726. ISSN 0098-5589.
  6. ^ Lau, Kung-Kiu; Velasco Elizondo, Perla; Wang, Zheng (2005). "Exogenous Connectors for Software Components". In Heineman, George T.; Crnkovic, Ivica; Schmidt, Heinz W.; Stafford, Judith A.; Szyperski, Clemens; Wallnau, Kurt (eds.). Component-Based Software Engineering. Lecture Notes in Computer Science. Vol. 3489. Springer Berlin Heidelberg. pp. 90–106. doi:10.1007/11424529_7. ISBN 9783540320494. S2CID 17971442.
  7. ^ MASH defines assets as people, property and information and management as monitoring, control and configuration. Presented at the 2013 IEEE IoT conference in Mountain View MASH includes a full IDE, Android client and runtime. "MASH YouTube channel"
  8. ^ A component-oriented approach is an ideal way to handle the diversity of software in consumer electronics. The Koala model, used for embedded software in TV sets, allows late binding of reusable components with no additional overhead. [1]
  9. ^ Component model for embedded devices like TV developed by Philips based on paper by van Ommering, R.: Koala, a Component Model for Consumer Electronics Product Software [2] Archived 2014-08-09 at the Wayback Machine
  10. ^ Larsen, John (2021). React Hooks in Action With Suspense and Concurrent Mode. Manning. ISBN 978-1720043997.
  11. ^ Arad, Cosmin (April 2013). Programming Model and Protocols for Reconfigurable Distributed Systems (PDF). Stockholm, Sweden: KTH Royal Institute of Technology. ISBN 978-91-7501-694-8. ((cite book)): |work= ignored (help)
  12. ^ Arellanes, Damian; Lau, Kung-Kiu (2017). "Exogenous Connectors for Hierarchical Service Composition" (PDF). 2017 IEEE 10th Conference on Service-Oriented Computing and Applications (SOCA). Kanazawa: IEEE. pp. 125–132. doi:10.1109/SOCA.2017.25. ISBN 9781538613269. S2CID 31211787.

Further reading