An AgentOriented Programming Language Targeting the Microsoft CLR AgentService and APX

1
An Agent-Oriented Programming Language Targeting
the Microsoft CLRAgentService and APX

• l . i . d . o .
• DIST - University of Genova

2
Introduction

• speaker Mauro Coccoli

3
Outline

• The Team
• Agent Platform
• Agent Oriented Language
• Portability Issues
• http//www.lido.dist.unige.it/ags.asp

4
The Team

• Mauro Coccoli
• Alberto Grosso
• Christian Vecchiola
• Daniele Marino
• Andrea Gozzi
• Academic Support by
• Prof. A. Boccalatte
• Prof. M. Paolucci

5
Agent Platform

• Runtime Agents
• Execution Environments
• Class Library

6
Agent Language

• Object Oriented Paradigm
• Agent Oriented Paradigm
• Improved Programmability

7
Portability Issues

• .NET
• Mono
• Rotor - SSCLI

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AgentServicePlatform

• speaker Alberto Grosso

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Summary

• Agents and MASs
• AgentService
• Platform Architecture
• Agent Model
• Runtime Environment

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Agents and MASs

• Agent
• Autonomous entity
• Intelligence
• Reactivity
• Pro-activeness
• Multi-behaviour

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Agents and MASs

• Multiagent system
• Community where agents interact in order to meet
  their goals
• Cooperation
• Competition
• Negotiation

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Agents and MASs

• Agent system applications
• Problems dealing with distributed and concurrent
  systems
• Electronic commerce and electronic markets
• Real time monitoring and management of
  telecommunication networks
• Information handling in information environments
  like the Internet
• Improving the flow of transport traffic
• Optimization of industrial manufacturing and
  production processes

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Agents and MASs

• FIPA
• The Foundation for Intelligent Physical Agents
• FIPA was formed in 1996 to produce software
  standards for heterogeneous and interacting
  agents and agent-based systems
• The aim is to provide standard strategies for
  agent communication, referring to industrial and
  commercial world

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Agents and MASs

• What does FIPA standardize?
• The platform architecture
• Agent communication
• Message structure
• Message exchange interaction protocols
• Content language (ACL)

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Agents and MASs

• Agent Programming Frameworks
• agent model definition
• platform architecture definition
• FIPA compliant
• agent implementation and scheduling
• communication system
• services (persistence, white and yellow pages, )
• integration with non-agent software and services

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AgentService

• Features
• Technology
• Common Language Infrastructure
• Platform
• FIPA abstract architecture compliance
• Extremely modular and customizable structure

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AgentService - Architecture
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AgentService Agent Model

• Knowledge
• Shared data structure
• Concurrent access
• Deadlock avoidance
• Persistence
• Behaviour
• Agent activity
• Concurrent execution
• Access to FIPA services
• Runtime environment
• Exposes platform services
• Messaging System, Persistence, Yellow and White
  Pages, Logging

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AgentService - Agent Model

• Agent Implementation
• Two different models
• Design Time AgentTemplate
• Run Time Agent
• An Agent is created upon an AgentTemplate
• The AgentTemplate defines the type of the agent
• Knowledge Units
• Behaviours
• The Agent is the run-time container of the
  AgentTemplate and binds the template to the
  platform execution environment

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AgentService Agent Model
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AgentService - Runtime

• Agent Scheduling
• Each Agent is deployed in a dedicated Application
  Domain
• Application Domain features
• intra-process structure
• execution boundaries for data and type isolation
• lightweight process
• security profile
• multi-threading

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AgentService - Runtime
logging
persistence
messaging
storage
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Agent Service - Conclusions

• AgentService
• Agent Model
• Modular Architecture
• Advanced Scheduling System
• Work in progress
• FIPA ACL
• A library of Agent, Knowledge, and Behaviour
  types ready to use
• AOSE methodology
• Interaction protocol designer (AUML)

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Agent Programming eXtensions

• speaker Christian Vecchiola

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Agent Programming eXtensions

• AO application development
• object-oriented frameworks
• framework programming patterns
• design to development gap
• agent oriented perspective for design
• object oriented perspective for code

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Agent Programming eXtensions

• Is OO programming too bad?
• ...obviously not
• powerful
• general purpose
• intuitive
• but....
• enhancements to support agent oriented development

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Agent Programming eXtensions

• APX
• facilities to define and handle new elements
  related to agent programming
• agent, behaviour and knowledge types
• a compiler
• applies the programming patterns required by
  AgentService
• checks the code

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Agent Programming eXtensions

• Is it feasible?
• the idea
• the new structural elements of APX simplify and
  speed up the code development
• the APX compiler is able to automate many of the
  task required by AgentService
• this is a practice already used in today
  compilers
• using statement implementation
• lock statement implementation

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Agent Programming eXtensions

• Is it feasible?
• the language
• only few syntactical and semantical elements have
  been added
• such elements are integrated into an object
  oriented programming language (C)
• the learning curve is very smooth

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Agent Programming eXtensions

• Is it feasible?
• the compiler
• changes to the compiler are only related to the
  front-end (scanner, parser, semantic analyzer)
• changes and add-on can be applied seamlessly to
  an already exixsting C compiler
• there are a lot of ready to use and modify C
  compilers
• SSCLI (aka rotor) csc
• Mono mcs
• Portable .NET

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Agent Programming eXtensions

• Features
• AgentService object model
• AgentTemplate class
• Knowledge class
• Behaviour class
• APX types
• agent template
• knowledge template
• behaviour template

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Agent Programming eXtensions

• agent template

agent AgentName init // definition
and creation of knowledge // and behaviour
that characterize the agent // agent setup
and initialization // mostly C code
.... done // agent cleanup and
resource release // mostly C code

APX provides a more agent oriented interface and
hides the underlying object oriented model of the
platform.
AgentService provides particular classes to
implement the previous agent model. It needs an
opportune programming pattern to develop a safe
agent.
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Agent Programming eXtensions

• knowledge template

knowledge JobKnowledge int JobID
System.DateTime ArrivalTime
System.DateTime StartingTime
System.DateTime StoppingTime MachineType
MachineRequestedType // every CLR object
// no pointers!!! // no APX templates!!
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Agent Programming eXtensions

• acquire statement

myKnow1.JobID 7 acquire (myKnow1, .)
// access here all the myKnow1 fields.. int
jobID myKnow1.JobID .. ..
myKnow1.ArrivalTime arrivalTime .. int
j myKnow1.JobID
myKnow1.JobID 7 // what happens is there is
an invocation to a knowledge // property without
acquiring a lock? // .... runtime exception try
this.LockKnowledge(myKnow1, .) //
access here all the myKnow1 fields.. int
jobID myKnow1.JobID .. ..
myKnow1.ArrivalTime arrivalTime
.. finally this.ReleaseKnowedge(true)
int j myKnow1.JobID
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Agent Programming eXtensions

• Implementation
• APX was developed by using the SSCLI as codebase
• clone of the sscli/clr/src/csharp/csharp tree
• modified elements
• scanner (introduction of the new tokens)
• parser (construction of new nodes in the
  syntactic tree)
• semantic analyzer (new checks added)

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Agent Programming eXtensions
CompilerHost
Compiler
lexer minor changes, recognize new tokens
front end
parser major changes, synthesys of new
constructs, additional information added to the
nodes
APX node builder parser support creates node
for the AgentService specific types, tags the
nodes with additional info
semantic analyzer no changes integration with
the new info added to the nodes
APX semantic analyzer performs additional checks
to ensure that the code is AgentService compliat
intermediate code generator no changes
emitter no changes
back end
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Agent Programming eXtensions
DEMO
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Agent Programming eXtensions

• Conclusions
• APX are a set of programming extensions to the C
  language to support agent programming
• APX were designed to..
• ..speed up the coding phase
• ..deliver useful tool to end user

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Portability Issues

• speaker Daniele Marino

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Why porting AgentService?

• CLI
• Virtual Execution
• Enviroment
• Nowadays
• Strong internetworking

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Rotor Mono Overview
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Rotor Mono Overview

• C Compilers and environment
• Rotor csc, clix
• Mono mcs, mono
• Framework Class Library
• Tools for debug and analisys

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Porting Issues

• Non standard libraries
• System.Xml
• Non standard behaviour
• System specific path
• Path separator symbol (/ vs \)
• Path termination character

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Conclusions

• Rotor
• .NET 1.0 Framework Supported
• Standard library implementations
• Lack of GUI development tool

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Conclusions

• Mono
• .NET 1.1 Framework Supported
• Active developing
• Work either on Linux or on OS X

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Thank you for your attention
www.lido.dist.unige.it