Lingua Franca: An IDL for Structural Subtyping Distributed Object
Systems
Patrick A. Muckelbauer and Vincent F. Russo
Department of Computer Sciences
Purdue University
West Lafayette, IN 47907
muckel,russo@cs.purdue.edu
Abstract
Recently the trend has been towards applying object-oriented
techniques to address problems of building scalable and maintainable
distributed systems. Object-oriented programming increases modularity
and data abstraction by supporting encapsulation through narrow,
rigidly defined and strongly enforced interfaces to
objects. Unfortunately, object-oriented interfaces and mechanisms are
usually only accessible and enforced through language mechanisms or
strict programming conventions. This severely limits the degree to
which disjoint, unrelated components can interact in a multilingual,
loosely coupled distributed system. An accepted solution to the
language dependence problem is the use of high-level interface
description languages (IDLs). IDLs provide a description mechanism for
an object's interface that is independent of any programming
language. In this paper we describe an interface description language
and runtime support system that uses structural subtyping rules rather
than the traditional interface name equivalence rules for conformance
checking. We argue that the choice of structural subtyping rather than
interface name equivalence leads to a less coupled and more extensible
distributed system.
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