Exploiting Transiently Shared Tuple Spaces for Location Transparent Code Mobility

Abstract

Code mobility greatly improves the flexibility of the architecture of a distributed application. However, currently available platforms do not exploit fully the potential of mobile code. For instance, remote dynamic linking of code is often restrained to a well-known site, and applications are prevented from manipulating their own code base. In this paper, we use the notion of transiently shared tuple space, originally introduced in the Lime coordination model, to overcome these limitations. We allow tuples to contain classes, and tuple spaces become the code base associated to the loading mechanism in the mobile code runtime support. Transient sharing allows for location transparent retrieval of classes, and accommodates changes determined by the reconfiguration of the system, e.g., due to mobility. In doing this, we effectively define a new coordination approach that deals uniformly with code and data. The presentation is completed by a proof-of-concept prototype, built by extending an existing Java-based mobile code toolkit.