JADE Book Trading - Multi-Agent Book Trading System

A Multi-Agent System (MAS) built with the JADE (Java Agent DEvelopment Framework), where autonomous software agents negotiate with each other to buy and sell books.

About

This is not a traditional web application. There is no central server. Instead, independent autonomous agents communicate, negotiate, and trade using FIPA (Foundation for Intelligent Physical Agents) standard messaging protocols.

What You Will Learn

• Fundamentals of Agent-Oriented Programming
• JADE Framework usage and agent lifecycle
• FIPA ACL (Agent Communication Language) messaging protocol
• Behaviour models: TickerBehaviour, CyclicBehaviour, OneShotBehaviour
• Yellow Pages service discovery via the Directory Facilitator
• Negotiation protocol: CFP (Call for Proposal) → PROPOSE → ACCEPT_PROPOSAL → INFORM

Negotiation Protocol (Step by Step)

Buyer Agent          Directory Facilitator         Seller Agent(s)
     |                        |                          |
     | 1. Search              |                          |
     |  "book-selling"        |                          |
     |----------------------->|                          |
     |                        |                          |
     | 2. Return seller list  |                          |
     |<-----------------------|                          |
     |                                                   |
     | 3. CFP: "Do you have Java 101?"                   |
     |-------------------------------------------------->|
     |                                                   |
     | 4a. PROPOSE: "Price: 50"                          |
     |<--------------------------------------------------|
     | 4b. REFUSE: "not-available"                       |
     |<--------------------------------------------------|
     |                                                   |
     | [Select lowest price]                             |
     |                                                   |
     | 5. ACCEPT_PROPOSAL: "I'll buy Java 101"           |
     |-------------------------------------------------->|
     |                                                   |
     | 6a. INFORM: "Purchase successful"                 |
     |<--------------------------------------------------|
     | 6b. FAILURE: "Already sold"                       |
     |<--------------------------------------------------|

Project Structure

BookTrading/
├── src/booktrading/
│   ├── BookBuyerAgent.java      # Buyer agent - searches for and purchases books
│   ├── BookSellerAgent.java     # Seller agent - manages catalogue and handles sales
│   ├── BookSellerGui.java       # Swing GUI for the seller agent
│   └── BookTrading.java         # Main class (entry point)
├── dist/
│   ├── BookTrading.jar          # Compiled JAR file
│   └── lib/
│       ├── jade.jar             # JADE framework library
│       └── commons-codec-1.3.jar
├── build.xml                    # Apache Ant build script
└── nbproject/                   # NetBeans IDE configuration

Class Details

BookBuyerAgent

An autonomous agent that searches for and purchases a target book.

Property	Description
Behaviour	TickerBehaviour - searches for sellers every 60 seconds
Strategy	Sends CFP to all sellers, accepts the lowest price offer
Startup Argument	Target book title (e.g. "Java 101")
Termination	Shuts down automatically after a successful purchase

Key Behaviours:

• TickerBehaviour: Periodically queries the Directory Facilitator for available sellers
• RequestPerformer (inner class): A 4-step state machine that drives the negotiation

BookSellerAgent

An agent that manages a book catalogue and handles incoming sales.

Property	Description
Catalogue	Hashtable<String, Integer> - maps book title to price
Service Registration	Registers as "book-selling" in the Directory Facilitator
GUI	Uses BookSellerGui for adding books via a graphical interface

Key Behaviours:

• OfferRequestsServer (CyclicBehaviour): Responds to CFP messages with a price proposal or refusal
• PurchaseOrdersServer (CyclicBehaviour): Processes purchase orders, removes sold books from catalogue

BookSellerGui

A Swing-based graphical interface for the seller agent.

• Text fields for book title and price
• "Add" button to insert books into the catalogue
• Closing the window terminates the agent

Prerequisites

Requirement	Version
Java JDK	1.8 or higher
Apache Ant	1.8.0+ (for building)
JADE	4.5.0 (included in dist/lib/)

Quick Start

Run the full demo with a single command (seller + buyer agents):

cd BookTrading/dist
java -cp "lib/jade.jar:lib/commons-codec-1.3.jar:BookTrading.jar" \
  jade.Boot -gui \
  "seller1:booktrading.BookSellerAgent;buyer1:booktrading.BookBuyerAgent(Java 101)"

This will open:

1. JADE RMA - the platform management GUI
2. Seller GUI - add books here (title + price → click Add)
3. Buyer Agent - automatically searches for "Java 101" every 60 seconds

Add Java 101 with any price in the Seller GUI and watch the buyer purchase it automatically.

Getting Started (Detailed)

1. Build from Source (Optional)

If you want to recompile the project:

cd BookTrading
ant clean build
ant jar

2. Start the JADE Platform

cd BookTrading/dist

# Option 1: Platform only (create agents manually via RMA GUI)
java -cp "lib/jade.jar:lib/commons-codec-1.3.jar:BookTrading.jar" \
  jade.Boot -gui

# Option 2: Platform + seller agents
java -cp "lib/jade.jar:lib/commons-codec-1.3.jar:BookTrading.jar" \
  jade.Boot -gui \
  "seller1:booktrading.BookSellerAgent;seller2:booktrading.BookSellerAgent"

# Option 3: Full demo (seller + buyer)
java -cp "lib/jade.jar:lib/commons-codec-1.3.jar:BookTrading.jar" \
  jade.Boot -gui \
  "seller1:booktrading.BookSellerAgent;buyer1:booktrading.BookBuyerAgent(Java 101)"

3. Add Agents via RMA GUI

From the JADE RMA (Remote Management Agent) GUI:

1. Go to Actions → Start New Agent
2. Agent Name: buyer1
3. Class Name: booktrading.BookBuyerAgent
4. Arguments: Java 101 (the book title to search for)

4. Add Books via the Seller GUI

When a seller agent starts, a GUI window will open:

1. Enter a book title in the Book title field (e.g. Java 101)
2. Enter a price in the Price field (e.g. 50)
3. Click Add

The buyer agent will discover this book within 60 seconds and automatically initiate the purchase process.

Example Run

Seller-agent seller1@localhost:1099/JADE is ready.
Java 101 inserted into catalogue. Price = 50

Hallo! Buyer-agent buyer1@localhost:1099/JADE is ready.
Target book is Java 101
Trying to buy Java 101
Found the following seller agents:
seller1@localhost:1099/JADE
Java 101 successfully purchased from agent seller1@localhost:1099/JADE
Price = 50
Buyer-agent buyer1@localhost:1099/JADE terminating.

Glossary

Term	Description
Agent	An autonomous, goal-driven software entity
Behaviour	A unit of work that an agent performs
ACL Message	Agent Communication Language message (FIPA standard)
CFP	Call for Proposal - a request for price offers
PROPOSE	A price offer reply
ACCEPT_PROPOSAL	Acceptance of a seller's offer
INFORM	Confirmation that a transaction completed successfully
REFUSE	Rejection (requested item not available)
FAILURE	Transaction failed (item already sold)
Directory Facilitator (DF)	Yellow pages service where agents register their services
RMA	Remote Management Agent - JADE platform management GUI
FIPA	Foundation for Intelligent Physical Agents - agent standards body
MAS	Multi-Agent System

Resources

• JADE Official Website
• JADE Programmer's Guide
• FIPA Specifications

License

This project is based on JADE examples and is licensed under the GNU Lesser General Public License v2.1.