Object-oriented Design Ontology - The Building-blocks of Object-oriented Design

The Building-blocks of Object-oriented Design

According to A Theory of Object-Oriented Design, the rudiments ('building-blocks') in the ontology of object-oriented design are as follows:

Individual entities:

• Classes
• Methods

Higher-dimensional entities

• Uniform sets of entities (sets of classes, sets of methods)
• Uniform sets of uniform sets (sets of sets of classes, sets of sets of methods)
• Class hierarchies (sets of classes such that all inherit from one)

Relations:

• Simple relations ('method m1 calls method m2', 'class subcls inherits from class supercls')
• Total relations ('all the concrete collections inherit from the Collection interface')
• Isomorphic relations ('each factory method creates and returns instances of a distinct product class')