Improving Exception Handling in Multi-agent Systems

Abstract

New software architectures based on multi-agents or software components allow the integration of separately developed software pieces that interact through various communication schemes. In such a context, reliability raises new important issues. This paper aims at increasing reliability in multi-agent systems (MASs) and, therefore, focuses on the study of an appropriate exception handling system (EHS). The issues specific to exception handling in MASs -preservation of the agent paradigm and support of cooperative concurrency -are presented and discussed. This paper analyses existing EHSs according to these issues and describes our proposition, the Sage system, which integrates various solutions from existing EHSs and adapts them to the agent paradigm. Sage is an exception handling system dedicated to MASs that addresses the stressed issues by providing means to coordinate the collective activities of agents, to embbed contextualized handlers in agents and to concert exceptions. It has been implemented and integrated in the MadKit MAS. It has been experimented with a classical travel agency case study.

Challenges for Exception Handling in Multi-Agent Systems

“…In the case of agents, Souchon et al proposed the SaGE 1 framework [18]. SaGE completes the exception handling system of Java with facilities to handle agent-specific issues.…”

Exception Handling and Asynchronous Active Objects: Issues and Proposal

“…As shown in our previous works [7,30], e ciently handling exceptions in concurrent systems using asynchronous communications requires cooperative concurrency to be supported, as for other concurrent systems [2,14].This amounts to provide a representation of collective activities and a way to de ne handlers ( 1) public class Broker implements AsyncActiveObject ( 2) { ( 3)…”

“…The issue with this approach is that supervisors are not encapsulated within the objects that experience the failure and therefore cannot access their internal state without breaking encapsulation. Our solution to prevent this, experimented in [3,7] is to de ne and encapsulate handlers within the object or activity they control.…”

“…It has been made available to AAO systems by recent research proposals [7,27]. It has to be noted that applying it to its whole extent excludes solutions in which an exception in a participant of a collaborative task is signaled to its brother participants.…”

“…This paper presents the speci cation of an evolution of the Sage exception handling system [7], which provides solutions to those issues in the context of systems developed with active objects using one way asynchronous communications and interacting via the request / response protocol. Such a context, in which synchronizations constraints are, when needed, handled at the application level, allows for a very generic view of what could be done regarding exception handling in all systems that use active objects.…”