A Generic Infrastructure for Decentralised Dynamic Loading of Platform-Specific Code

Abstract

Abstract. Dynamic loading of code is a crucial and often neglected part of today's distributed systems that face increasing dynamics, complexity and heterogeneity. Ubiquitous computing and mobile computing even strengthen this trend. As the local availability of suitable code cannot be assumed in such environments, we propose a generic, decentralised code loading infrastructure. The whole process of publication, look-up, implementation selection and the final loading of platform-specific code is decentralised and requires only basic peerto-peer functionality. In contrast to previous work, our infrastructure allows any peer participating in the network to offer and to obtain platform-specific code in a dynamic and heterogeneous environment. By building on our generic concept, we present a JXTA-based service for dynamic code loading, which is realised by extending and improving JXTA-built-in mechanisms for dynamic service integration. Subsequently, we show the practical application of our infrastructure by an integration into our CORBA middleware and an implementation of mobile objects and mobile web services.

Using Object Replication for Building a Dependable Version Control System

“…This profile contains a unique object ID, a specification of the initial fragment type to load and contact information of other fragments. The initial fragment type can be specified in a language-independent way; a code-loading service [13] is used for obtaining the corresponding code for the local platform. The contact data in the APX profile contains information about the replica group.…”

Adaptive Web Service Migration

“…The AWSMGenericFactory Web service is responsible for creating a SAM-WSfacet-specific AWSMFactory Web service. We need this delegation mechanism for integration of our dynamic code loading infrastructure [8], because it allows loading the AWSMFactory code before creation (see Section 4.4). Direct registration of an AWSMFactory at the AWSMFactoryFinder is possible as well.…”

“…We developed a decentralised code loading service (P2P-DLS) [8]. It allows any peer to offer and to obtain platform-specific code.…”

“…Unlike our previous work on context-aware migration of CORBA objects [7], in this paper we propose the use of standard Web service technology as core mechanism, which simplifies interoperability between heterogeneous infrastructures of different vendors and allows disconnected operation. On the basis of our dynamic code loading infrastructure [8], the platform contains a novel dynamic deployment service that allows service migration to machines on which the needed code is unavailable and thus has to be loaded on demand. We support client-transparent migration by providing persistent Web service references for the whole life cycle by introducing a persistent Web service identity.…”

Grid Anywhere: Um middleware extensível para grades computacionais desktop

“…A opção de utilização do JXTA é uma alternativa atrativa para a carga de classes de forma descentralizada, sendo resolvidos, inclusive, os problemas de conectividade apresentados anteriormente [87]. No entanto, é preciso que as aplicações sejam desenvolvidas utilizando essa plataforma.…”