Release 10.1A: OpenEdge Getting Started:
Object-oriented Programming

Abstraction

An abstraction defines the contract for a class to the consumers of the class, which states the set of functionality that the class agrees to provide in a certain way. This contract represents general functionality that can be specified in greater detail. To support the abstraction it represents, a class defines a public interface that other objects can use to communicate with it. (A public interface specifies the means by which any class can access another class’s functionality.) The importance of abstraction is that the compiler is able to enforce the contract that it defines between different classes.