7.3.1 Dynamical Instantiation

In order to allow the Persistent Storage Manager the autonomous control of its dedicated objects, their classes have to follow some conventions which enable the Persistent Storage Manager to save and restore them in a fully abstract manner. The convention of printed representation serves for this purpose. According to this convention, an object produces a printed representation of itself when its :dump method is invoked. Moreover, this printed representation is expected by the object's constructor :isnew, when an exact copy of the object is re-instantiated.

Program 7.2 lists the definition of a class of objects for the representation of bound floating point values and Example 7.1 shows the printed representation of these objects. Example 7.1 is the result of the :dump method of an object modeling a floating point number bound between $[0.3\/\mbox{,}\/2.7]$ with a value of 1.5.