In computing, subject-oriented programming is an object-oriented software paradigm in which the state (fields) and behavior (methods) of objects are not seen as intrinsic to the objects themselves, but are provided by various subjective perceptions ("subjects") of the objects. The term and concepts were first published in September 1993 in a conference paper which was later recognized as being one of the three most influential papers to be presented at the conference between 1986 and 1996. As illustrated in that paper, an analogy is made with the contrast between the philosophical views of Plato and Kant with respect to the characteristics of "real" objects, but applied to software ones. For example, while we may all perceive a tree as having a measurable height, weight, leaf-mass, etc., from the point of view of a bird, a tree may also have measures of relative value for food or nesting purposes, or from the point of view of a tax-assessor, it may have a certain taxable value in a given year. Neither the bird's nor the tax-assessor's additional state information need be seen as intrinsic to the tree, but are added by the perceptions of the bird and tax-assessor, and from Kant's analysis, the same may be true even of characteristics we think of as intrinsic.
Subject-oriented programming advocates the organization of the classes that describe objects into "subjects", which may be composed to form larger subjects. At points of access to fields or methods, several subjects' contributions may be composed. These points were characterized as the join-points of the subjects. For example, if a tree is cut down, the methods involved may need to join behavior in the bird and tax-assessor's subjects with that of the tree's own. It is therefore fundamentally a view of the compositional nature of software development, as opposed to the algorithmic (procedural) or representation-hiding (object) nature.
"SIGSOFT - ACM Special Interest Group on Software Engineering".
↑ Harold Ossher, Peri Tarr. Hyper/J: Multi-dimensional separation of concerns for Java, Proceedings of the 23rd International Conference on Software Engineering, Toronto, Ontario, Canada, 2001, Pages: 821 - 822
↑ William Chung, William Harrison, Vincent Kruskal, Harold Ossher, Stanley M. Sutton, Jr., Peri Tarr, Matthew Chapman, Andrew Clement, Helen Hawkins, Sian January. The concern manipulation environment, Proceedings of the 27th international conference on Software engineering table of contents, St. Louis, MO, USA, 2005
↑ William Harrison, Harold Ossher, Stanley Sutton, Peri Tarr. Concern modeling in the concern manipulation environment, Proceedings of the 2005 workshop on Modeling and analysis of concerns in software, St. Louis, Missouri, 2005
↑ William Harrison, Harold Ossher, Peri Tarr. General Composition of Software Artifacts, Proceedings of Software Composition Workshop 2006, March 2006, Springer-Verlag, LNCS 4089, pages 194-210
↑ "Journal of Object Technology: Context Oriented Programming".