In aspect-oriented software development, cross-cutting concerns are aspects of a

program Program, programme, programmer, or programming may refer to: Business and management * Program management, the process of managing several related projects * Time management * Program, a part of planning Arts and entertainment Audio * Programm ...

that affect several modules, without the possibility of being encapsulated in any of them. These concerns often cannot be cleanly decomposed from the rest of the system in both the design and implementation, and can result in either ''scattering'' ( code duplication), ''tangling'' (significant dependencies between systems), or both. For instance, if writing an application for handling

medical records The terms medical record, health record and medical chart are used somewhat interchangeably to describe the systematic documentation of a single patient's medical history and care across time within one particular health care provider's jurisdi ...

, the indexing of such records is a

core concern Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central ...

, while logging a history of changes to the record database or user database, or an authentication system, would be cross-cutting concerns since they interact with more parts of the program.

Background

Cross-cutting concerns are parts of a program that rely on or must affect many other parts of the system. They form the basis for the development of aspects. Such cross-cutting concerns do not fit cleanly into object-oriented programming or

procedural programming Procedural programming is a programming paradigm, derived from imperative programming, based on the concept of the ''procedure call''. Procedures (a type of routine or subroutine) simply contain a series of computational steps to be carried ...

. Cross-cutting concerns can be directly responsible for ''tangling'', or system inter-dependencies, within a

. Because procedural and functional language constructs consist entirely of procedure calling, there is no semantic through which two goals (the capability to be implemented and the related cross-cutting concern) can be addressed simultaneously. As a result, the code addressing the cross-cutting concern must be ''scattered'', or duplicated, across the various related locations, resulting in a loss of

modularity Broadly speaking, modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a sy ...

Aspect-oriented programming In computing, aspect-oriented programming (AOP) is a programming paradigm that aims to increase modularity by allowing the separation of cross-cutting concerns. It does so by adding behavior to existing code (an advice) ''without'' modifying ...

aims to encapsulate cross-cutting concerns into aspects to retain modularity. This allows for the clean isolation and reuse of code addressing the cross-cutting concern. By basing designs on cross-cutting concerns, software engineering benefits can include modularity and simplified maintenance.

Examples

Examples of concerns that tend to be cross-cutting include: *

Business rule A business rule defines or constrains some aspect of business. It may be expressed to specify an action to be taken when certain conditions are true or may be phrased so it can only resolve to either true or false. Business rules are intended to ass ...

s * Caching *

Code mobility In distributed computing, code mobility is the ability for running programs, code or objects to be migrated (or moved) from one machine or application to another. This is the process of moving mobile code across the nodes of a network as opposed ...

Data validation In computer science, data validation is the process of ensuring data has undergone data cleansing to ensure they have data quality, that is, that they are both correct and useful. It uses routines, often called "validation rules", "validation cons ...

* Domain-specific optimizations *

Environment variables An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP en ...

and other global configuration settings *

Error detection and correction In information theory and coding theory with applications in computer science and telecommunication, error detection and correction (EDAC) or error control are techniques that enable reliable delivery of digital data over unreliable communi ...

* Internationalization and localization which includes

Language localisation Language localisation (or language localization) is the process of adapting a product's translation to a specific country or region. It is the second phase of a larger process of product translation and cultural adaptation (for specific countries ...

Information security Information security, sometimes shortened to InfoSec, is the practice of protecting information by mitigating information risks. It is part of information risk management. It typically involves preventing or reducing the probability of unauthoriz ...

* Logging * Memory management *

Monitoring Monitoring may refer to: Science and technology Biology and healthcare * Monitoring (medicine), the observation of a disease, condition or one or several medical parameters over time * Baby monitoring * Biomonitoring, of toxic chemical compounds, ...

* Persistence * Product features * Real-time constraints *

Synchronization Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronou ...

* Transaction processing * Context-sensitive help * Privacy * Computer security

References

Bibliography

* * * * *

External links

AOSD.net's
glossary of aspect oriented terms (vi
Internet Archive Wayback Machine
AOSD.net has becom
Modularity
. *

AspectJ AspectJ is an aspect-oriented programming (AOP) extension created at PARC for the Java programming language. It is available in Eclipse Foundation open-source projects, both stand-alone and integrated into Eclipse. AspectJ has become a widely use ...

br>
an Aspect-Oriented extension to the Java (programming language), Java programming language *Bergmans, L., M. Aksit (2001): Composing Multiple Concerns Using Composition Filters, https://web.archive.org/web/20170909131212/http://trese.cs.utwente.nl/ (24 July 2004) *Berg, K. van den, Conejero, J. and Chitchyan, R. (2005). AOSD Ontology 1.0 ‐ Public Ontology of Aspect‐Orientation. AOSD Europe Network of Excellence, http://eprints.eemcs.utwente.nl/10220/01/BergConChi2005.pdf *Here is an example of handling a cross-cutting concern: https://web.archive.org/web/20161220151503/https://www.captechconsulting.com/blogs/a-persistence-pattern-using-threadlocal-and-ejb-interceptors {{aosd Aspect-oriented software development Aspect-oriented programming

Background

Examples

See also

References

Bibliography

Further reading

External links