Cross-cutting concern
In
aspect-oriented software development, cross-cutting concerns are aspects of a program that affect several modules, without the possibility of being encapsulated
in any of them.
These code duplication
), tangling (significant dependencies between systems), or both.
For instance, if writing an
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.[1] Such cross-cutting concerns do not fit cleanly into object-oriented programming or procedural programming.[2]
Cross-cutting concerns can be directly responsible for tangling, or system inter-dependencies, within a
modularity.[2]
aspects to retain modularity. This allows for the clean isolation and reuse of code addressing the cross-cutting concern.[4] By basing designs on cross-cutting concerns, software engineering benefits can include modularity and simplified maintenance.[5]
Examples
Examples of concerns that tend to be cross-cutting include:
- Business rules
- Caching
- Code mobility
- Data validation
- Domain-specific optimizations
- Environment variablesand other global configuration settings
- Error detection and correction
- Internationalization and localization which includes Language localisation
- Information security
- Logging
- Memory management
- Monitoring
- Persistence
- Product features
- Real-time constraints
- Synchronization
- Transaction processing
- Context-sensitive help
- Privacy
- Computer security
See also
- Separation of concerns
- Aspect-oriented programming
- Code refactoring (restructuring software)
- Database normalization (minimize needlessly replicated data)
- Multiple inheritance
- Microservices
- Orthogonalization (mathematical normalization)
References
- ^ Kiczales et al. 2002, p. 4
- ^ a b Kiczales et al. 1997, p. 1
- ^ Kiczales et al. 1997, p. 6
- ^ Kiczales et al. 1997, p. 2
- ^ Li, Krishnamurthi & Fisler 2002, p. 1
Bibliography
- Kiczales, Gregor; Lamping, John; Mendhekar, Anurag; Maeda, John; Lopes, Cristina; Longtier, Jean-Marc; Irwin (1997). "Aspect-Oriented Programming". Proceedings of the 11th European Conference on Object-Oriented Programming (ECOOP 1997): 220–242.
- US patent 6467086, Kiczales et al., "Aspect-oriented programming", issued 2002-10-15
- Li, Harry; Krishnamurthi, Shriram; Fisler, Kathi (2002). "Verifying Cross-Cutting Features as Open Systems". ACM SIGSOFT Software Engineering Notes. 27 (6): 89–98. S2CID 52835673.
- Parnas, David L. (December 1972). "On the Criteria To Be Used in Decomposing Systems into Modules". S2CID 53856438.
- Tarr, Peri; Ossher, Harold; Harrison, William; Sutton, Stanley M. Jr. (1999). "N degrees of separation: Multi-dimensional separation of concerns". Proceedings of the 1999 International Conference on Software Engineering (IEEE Cat. No.99CB37002). Los Angeles, California, USA: ISBN 978-1-58113-074-4.
Further reading
- Laddad, R. (2003): AspectJ in Action, Practical Aspect-Oriented Programming, Manning Publications Co.
External links
- AOSD.net's glossary of aspect oriented terms (via Internet Archive Wayback Machine; AOSD.net has become Modularity).
- AspectJ [1], an Aspect-Oriented extension to the 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
