An aspect of a program is a feature linked to many other parts of the program, but which is not related to the program's primary function. An aspect crosscuts the program's core concerns, therefore violating its

separation of concerns In computer science, separation of concerns is a design principle for separating a computer program into distinct sections. Each section addresses a separate '' concern'', a set of information that affects the code of a computer program. A concern ...

that tries to encapsulate unrelated functions. For example,

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply cha ...

code can crosscut many modules, yet the aspect of logging should be separate from the functional concerns of the module it cross-cuts. Isolating such aspects as logging and persistence from business logic is at the core of the aspect-oriented programming (AOP)

paradigm In science and philosophy, a paradigm () is a distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitute legitimate contributions to a field. Etymology ''Paradigm'' comes f ...

. Aspect-orientation is not limited to programming since it is useful to identify, analyse, trace and modularise concerns through requirements elicitation, specification and design. Aspects can be multi-dimensional by allowing both functional and non-functional behaviour to crosscut any other concerns, instead of just mapping non-functional concerns to functional requirements. 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

weaving Weaving is a method of textile production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. Other methods are knitting, crocheting, felting, and braiding or plaiting. The longitudinal ...

them together (a process also called composition), one finally produces a whole out of the separate aspects. This approach is known as pure aspect programming, but hybrid approaches are more commonly used. 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.

References

{{aosd Aspect-oriented software development Aspect-oriented programming