Object-Oriented Finite Elements: From Smalltalk to Java']Java

Since the middle of the 1980s, the object-oriented programming has gained more and more attention in the computational mechanics community. Although the most popular language used today is C++, several languages have been used since the beginning of the object-oriented era. In this chapter, we first try to draw a panel of object-oriented approaches developed in the past years, and second to draw the main lines to design modem computational codes. From an industrial point of view, this choice remains crucial and beyond the technical problems, it may have tremendous economic consequences. The choice of the programming language may have a dramatic impact on the software architecture and cannot be considered as a simple technical choice. Several authors proposed new features based on software engineering techniques such as design patterns. This kind of approach is mandatory to handle the growing complexity of the problems addressed today, usually involving several physics at different space and time scales, and implemented on heterogeneous distributed computer systems. We advocate that a global philosophy involving a single programming paradigm in a complete environment capable of managing hardware (memory, network, GUI,...) is needed to handle this global complexity. Some basic code features are described.