Software framework · WikiHole

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Comparison with libraries

Software frameworks differ from standard libraries in key ways:

Inversion of control: In a library, user code controls the program's flow and calls library functions as needed. In a framework, the framework controls the flow and calls user code at specific points, often via the Template Method Pattern.
Default behaviour: Frameworks provide pre-implemented functionality (e.g., standard features or workflows) that can be used as-is or customized within a predefined structure. Libraries, by contrast, require user code to assemble and configure functionality.
Structured extensibility: Frameworks enable new features or altered behaviour through structured mechanisms such as hooks, callbacks, or APIs. Libraries allow extensibility but without predefined integration points, relying on user code for integration.
Open-closed principle: The framework's core logic is generally fixed, allowing extensions (e.g., plugins or subclasses) but not modification of the framework itself.

Pattern

According to Pree,² software frameworks consist of frozen spots and hot spots. Frozen spots define the overall architecture of a software system, that is to say its basic components and the relationships between them. These remain unchanged (frozen) in any instantiation of the application framework. Hot spots represent the parts where the programmers using the framework add their own code to add the functionality specific to their own project.

The necessary functionality can be implemented by using the Template Method Pattern in which the frozen spots are known as invariant methods and the hot spots are known as variant or hook methods. The invariant methods in the superclass provide default behaviour while the hook methods in each subclass provide custom behaviour.

When developing a concrete software system with a software framework, developers utilize the hot spots according to the specific needs and requirements of the system. Software frameworks rely on the Hollywood Principle: "Don't call us, we'll call you."³⁴ This means that the user-defined classes (for example, new subclasses) receive messages from the predefined framework classes. Developers usually handle this by implementing superclass abstract methods.

Tradeoffs

One potential downside of using a framework is that it adds to the size of a program, a phenomenon termed code bloat. This can be exacerbated by using multiple, sometimes competing, frameworks in the same codebase.

Learning how to use a framework can be substantial. The intended efficiencies of using the framework may be outweighed by the cost to learn it, especially for a framework that is new to the development staff.⁵ However, once a framework is learned, development team speed may increase for future work. Learning how to use a framework can be substantial. The intended efficiencies of using the framework may be outweighed by the cost of learning it, especially for a framework that is new to the development staff.[5] However, once a framework is learned, development team speed may increase for future work.

Some claim that the most effective frameworks evolve from re-factoring an existing solution, such as a generic one-size-fits-all framework developed by third parties for general purposes, rather than from green-field development.

Recently, Microsoft Research launched an open-source project that covers software engineering, web navigation, and personal assistant tasks, with training data and evaluation methods available to researchers.⁶

Examples

A framework generally focuses on a specific problem domain, including:

Artistic drawing, music composition, and mechanical CAD⁷⁸
Financial modeling applications⁹
Earth system modeling applications¹⁰
Decision support systems¹¹
Media playback and authoring
Web framework
Middleware
Application framework – General GUI applications
Enterprise Architecture framework

Some notable frameworks:

Cactus Framework – High performance scientific computing
Oracle Application Development Framework
Laravel (PHP Framework)
Pipedream
Php4delphi
Vue Native
OpenSilver - enables legacy applications based on Microsoft Silverlight, , and to be ported into applications

See also

Class (computer programming) – Computer programming structure used to create objectsPages displaying short descriptions of redirect targets
Don't repeat yourself – Principle of software development
Implicit invocation
Software design pattern – Reusable solution template to a commonly-needed software behavior
Software engine – Core component of a complex software system
Software platform – Environment in which a piece of software is executedPages displaying short descriptions of redirect targets

References

1Riehle, Dirk (2000), Framework Design: A Role Modeling Approach (PDF), Swiss Federal Institute of Technology
2Pree, W (1994), "Meta Patterns: A Means for Capturing the Essentials of Reusable Object-Oriented Design", Proceedings of the 8th European Conference on Object-Oriented Programming, Lecture Notes in Computer Science, vol. 821, Springer-Verlag, pp. 150–162, CiteSeerX 10.1.1.74.7935, doi:10.1007/BFb0052181, ISBN 978-3-540-58202-1 {{citation}}: Cite uses deprecated parameter |citeseerx= (help)
3Larman, C (2001), Applying UML and Patterns: An Introduction to Object-Oriented Analysis and Design and the Unified Process (2nd ed.), Prentice Hall, ISBN 978-0-13-092569-5
4Gamma, Erich; Helm, Richard; ; (1994). . Addison-Wesley. .

External links

The dictionary definition of software framework at Wiktionary
Media related to Software frameworks at Wikimedia Commons