Some limitations of object-oriented design

Object-oriented design is improving the systems analyst´s ability to develop software in forms which map to the problem space (“real world”), provide modular structures to systems under analysis and design, are more easily maintained and modified, and provide for reusability of software segments. Object-oriented designs are also easier to test. The real world, however, has many phenomena which are not easy to assign to “blocks” of information at specific levels of analysis. Real-world phenomena often operate in defiance of a simple object decomposition. Many parts of the real world are continuous, not discrete, and the choice of where objects begin and end in an object-based design can be difficult to discern or may be quite arbitrary. The arbitrary choice of objects can create complex interfaces between the objects. This paper presents several cases where the “real world” behaves as a continuum. The first and second cases are drawn from electrical engineering to highlight some of the problems inherent in carrying object-oriented decomposition to very fine detail. The third case, from basic physics, details the sources and effects of gyroscopic forces. The fourth case deals with the problem of conceptual objects, which are objects needed to complete a design that does not represent articles of hardware or easily identified discrete entities in the world