Aspect (computer programming): Difference between revisions

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{{Short description|Feature linked to many parts of a program, unrelated to program's primary function}}

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In [[computer scienceprogramming]], an '''aspect''' is a part of a program thatis cross-cuts itsa [[coreSoftware concernfeature|feature]]s, thereforelinked violatingto itsmany [[separationother parts of concerns]].the program, Itbut is anot feature linkedrelated to manythe partsprogram's ofprimary afunction. An aspect [[Cross-cutting concern|crosscuts]] the program's core concerns, buttherefore whichviolating isits not[[separation necessarilyof theconcerns]] primarythat functiontries ofto theencapsulate programunrelated functions. For example, [[Data logging|logging]] code can cross-cutcrosscut many modules, yet the aspect of logging should be separate from the functional concerns of the module it cross-cuts. Isolating such aspects as [[Data logging|logging]] and [[persistence (computer science)|persistence]] from [[business logic]] is at the aimcore of [[aspect-oriented software development]] (AOSD), of which the [[aspect-oriented programming]] (AOP) [[programming paradigm|paradigm]] is the most widely employed.<ref>{{citebookcite book|title=Aspect-Oriented Database Systems|url=https://archive.org/details/springer_10.1007-978-3-662-05851-0|author=Awais Rashid|year= 2004|publisher=Springer|isbn=35400094853-540-00948-5}}</ref>

Aspect-orientation is not limited to programming since it is useful to identify, analyse, trace and modularise concerns (e.g., PREview) through requirements elicitation, specification, and design. Aspects can be multi-dimensional by allowing both functional and non-functional behaviour to cross cutcrosscut any other concerns, instead of just mapping non-functional concerns to functional requirements.{{factCitation needed|date=April 2010}}.

In [[computer science]], an '''aspect''' is a part of a program that cross-cuts its [[core concern]]s, therefore violating its [[separation of concerns]]. It is a feature linked to many parts of a program, but which is not necessarily the primary function of the program. For example, logging code can cross-cut many modules, yet the aspect of logging should be separate from the functional concerns of the module it cross-cuts. Isolating such aspects as [[Data logging|logging]] and [[persistence]] from [[business logic]] is the aim of [[aspect-oriented software development]] (AOSD), of which the [[aspect-oriented programming]] (AOP) [[programming paradigm|paradigm]] is the most widely employed.<ref>{{citebook|title=Aspect-Oriented Database Systems|author=Awais Rashid|year= 2004|publisher=Springer|isbn=3540009485}}</ref>

One view of [[aspect-oriented software development]] is that every major feature of the program, core concern (business logic), or [[cross-cutting concern]] (additional features), is an aspect, and by [[aspect-oriented programming#Weavingweaver|weaving]] them together (a process also called composition), youone finally produceproduces a whole out of the separate aspects. This approach is known as pure aspect programming, but hybrid approaches are more commonly used, perhaps since there is less of a paradigm shift between object- and aspect-oriented programming. There is a similar situation with early aspect software development (e.g., requirements), with traditional methods being enhanced for aspect-orientation and new models proposed. Non-functional concerns (e.g., security) can crosscut functional concerns (e.g., door must be present)common. It is possible for functional concerns to crosscut non-functional or functional concerns (e.g., the need for more features harms mobility). A uniform approach to representation and composition, similar to the pure approach in AOP, is termed multidimensional representation.{{Citation needed|date=April 2010}}

Aspect-orientation is not limited to programming since it is useful to identify, analyse, trace and modularise concerns (e.g., PREview) through requirements elicitation, specification and design. Aspects can be multi-dimensional by allowing both functional and non-functional behaviour to cross cut any other concerns, instead of just mapping non-functional concerns to functional requirements{{fact}}.

One view of [[aspect-oriented software development]] is that every major feature of the program, core concern (business logic), or [[cross-cutting concern]] (additional features), is an aspect, and by [[aspect-oriented programming#Weaving|weaving]] them together (a process also called composition), you finally produce a whole out of the separate aspects. This approach is known as pure aspect programming, but hybrid approaches are more commonly used, perhaps since there is less of a paradigm shift between object- and aspect-oriented programming. There is a similar situation with early aspect software development (e.g., requirements), with traditional methods being enhanced for aspect-orientation and new models proposed. Non-functional concerns (e.g., security) can crosscut functional concerns (e.g., door must be present). It is possible for functional concerns to crosscut non-functional or functional concerns (e.g., need for more features harms mobility). A uniform approach to representation and composition, similar to the pure approach in AOP, is termed multidimensional representation.

The prism analogy describes aspects with terms from the ___domain of light. Like splitting light into its many aspects (different colours) with a prism, you split a problem into its separate aspects. With another prism you can put the different colours back into a white ray of light, and by the process of weaving aspects you can put your solutions for the different aspects of a problem back into a solution for the whole problem.

== See also ==

[[AspectJ]]

== References ==

{{reflist}}

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<references />

{{aosd}}

[[Category:Aspect-oriented software development]]

[[Category:Aspect-oriented programming]]