3.6 Summary

In modeling object-oriented applications, one of the first tasks is to identify the objects and collections of similar objects in the problem domain. An object has properties and behaviors. The class is a definition of objects with the same characteristics.

A model is an abstract representation of a real system. Modeling is the process of constructing representations of objects and defining the common characteristics into classes. Modeling involves what objects and relevant characteristics of these objects are to be included in the model.

Objects collaborate by sending messages to each other. A message is request to to carry out a certain operation by an object. Information hiding emphasizes the separation of the list of operations that an object offers to other objects from the implementation details that are hidden to other objects.