Strategic Research Directions in Object Oriented Programming

This report is an overview of the eld of object oriented programming. It presents a brief historical perspective of the eld, then summarizes some major achievements. Four strategic research directions are then presented: technologiesintegration,software components, distributedprogramming, and open implementations. Object-oriented programming (OOP) is a technique for improving productivity, quality, and innovation in software development. Whereas procedures are sequences of statements that specify a transformation from inputs to outputs, objects are collections of operations sharing a state that provide persistent services over time. A procedure-oriented system consists of sequentially executed procedures, while an object-oriented system consists of a collection of interacting objects. Procedures express algorithms that implement computable functions, while objects express embedded systems that implement services over time, like banking or airline-reservation applications. Objects typically possess mutable state, operations that change their state, and operations that cause them to in turn invoke operations on other objects. Operations may be described through a well deened interface providing information about attributes and actions visible from clients. The implementation of each object is encapsulated { hidden from clients of the object.