vineri, septembrie 16, 2005

Domain Driven Design -> citate

Inca doua citate din Domain Driven Design. Autorul da si un exemplu clar intre modelarea obiectuala si “modelarea” procedurala a unei aceeasi probleme.

“Object-oriented programming is powerful because it is based on a modeling paradigm, and it provides implementations of the model constructs. As far as the programmer is concerned, objects really exist in memory, they have associations with other objects, they are organized into classes, and they provide behavior available by messaging. Although many developers benefit from just applying the technical capabilities of objects to organize program code, the real breakthrough of object design comes when the code expresses the concepts of a model. Java and any other tools allow the creation of objects and relationships directly analogous to conceptual object models.”

“MODEL-DRIVEN DESIGN has limited applicability using languages such as C, because there is no modeling paradigm that corresponds to a purely procedural language. Those languages are procedural in the sense that the programmer tells the computer a series of steps to follow. Although the programmer may be thinking about the concepts of the domain, the program itself is a series of technical manipulations of data. The result may be useful, but the program doesn't capture much of the meaning. Procedural languages often support complex data types that begin to correspond to more natural conceptions of the domain, but these complex types are only organized data, and they don't capture the active aspects of the domain. The result is that software written in procedural languages has complicated functions linked together based on anticipated paths of execution, rather than by conceptual connections in the domain model. “