GreenVest – Carbon Credit Trading Platform

A lightweight MVC-based prototype implementing Buyer, Seller, and Admin workflows with JSON storage and core software design patterns (Observer, Factory, Decorator, State, Interceptor, Singleton).
This project was developed for CS6451 Advanced Software Design. Team member : Vaitheeshwar, Pranav , Ganga, Yashwitha

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📌 Project Overview

GreenVest is a carbon credit trading prototype where:

• Sellers submit and list verified carbon credits for sale
• Buyers purchase credits, manage portfolios, view receipts, and track balances
• Admins verify sustainability actions and approve credits

The system uses file-based JSON storage, MVC architecture, and multiple design patterns to replicate real marketplace behaviour.

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🎯 Key Features

✔ Buyer Module

• Register / Login
• View available credits
• Purchase credits (with rule validation)
• Receive receipts (Factory Pattern)
• View decorated receipts (Decorator Pattern)
• View credit portfolio (State + Observer Pattern)
• View account summary (balance + credit statistics)

✔ Seller Module

• Register / Login
• List credits for sale
• Update credit prices
• Track their own credit inventory

✔ Admin Module

• Login
• Verify seller credit submissions
• Approve or reject credits
• Manage minimum pricing rules

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🧩 Architecture Summary (MVC + Microkernel)

✔ View Layer

Handles ONLY input/output (console).
Examples:

• BuyerView.java
• SellerView.java
• AdminView.java

✔ Controller Layer

Middleware enforcing role access & linking view → service.
Examples:

• BuyerController.java
• SellerController.java

✔ Service Layer

Business logic goes here.
Examples:

• BuyerService.java
• SellerService.java
• AuthService.java

✔ Repository Layer

Reads/writes JSON files.
Examples:

• UsersRepositoryJSON.java
• ReceiptRepositoryJSON.java
• PortfolioRepositoryJSON.java

✔ Microkernel Rule Engine

Applies rules during purchase:

• Compliance Rule
• Expiry Rule (optional extension)

✔ Design Patterns Used

Pattern	Where Used	Purpose
MVC	Entire project	Separation of concerns
Singleton	JSON repositories	One instance for consistency
Factory	Receipt creation	Auto-generate receipt objects
Decorator	Receipt printing	Add header/footer dynamically
Observer	Expiry alerts	Notify buyers of expired credits
State	Credit lifecycle	Active vs Expired credits
Interceptor	Authentication	Block unauthorized access

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