SaveTheGovernment

Table of Contents

• Application Description
• User Roles
• App Usage Instructions
• Repository Structure
• System Architecture
• System Requirements
• Software Patterns
• Algorithms
• Installation
• Running the Application
• API Documentation
• Repository Statistics
• Contribution
• License

Government budget management system that allows different types of users to view, manage, and approve changes to the national budget.

Application Description

SaveTheGovernment is a graphical application that manages the government budget.Includes data for budgets from year 2019 till 2026. The application supports multiple user types with different access rights and allows:

• Viewing the overall budget
• Viewing the change history
• Viewing statistics (distribution comparisons and time trend analysis, while estimating their future trajectory.)
• Managing budget items
• Submitting change requests
• Approving or rejecting change requests
• Recording all changes in a change log

User Roles

The application supports four types of users with different access rights:

1. Citizen

• View the overall budget
• View the change history
• View statistics
• Update personal information (username, password, name)

2. Government Member

Includes all Citizen permissions, plus:

• Submit requests for budget fund modifications
• View the history of change requests

3. Finance Ministry Member

Includes all Government Member permissions, plus:

• Directly manage budget items

4. Prime Minister

• View the overall budget
• View the change history
• View statistics
• Approve or reject pending change requests

Note: Only one Prime Minister can exist in the system (Singleton pattern).

App Usage Instructions

1. Logging into the application:

• Register with your credentials and select your role (Citizen, GovernmentMember, PrimeMinister).
• Log in to an existing account. For convenience, the following accounts are already available:
  • Citizen: username: lakis, password: Lakis123!
  • GovMember (Finance Ministry): username: kammenos, password: Kammenos123!
  • PrimeMinister: username: mitsotakis, password: Mitsotakis123!

2. App navigation:

• You can navigate the application using the sidebar.
• Remember that the application's features update dynamically depending on the user role.

3. View the State Budget:

• Select View Total budget from the sidebar
• Click on year and select a year to display the budget for that specific year. (default year: 2026)
• Click the button that appears at the top right to filter the budget table in various ways.

4. Editing a Budget Item:

• After logging in exclusively as Finance Minister.
• Select View Total budget from the sidebar.
• Click edit on the budget item of your choice.
• Enter the new amount and click save to confirm your change.

5. View Pending Changes:

• After logging in as a Government Member.
• Select View Pending Changes from the sidebar.
• Select Create New Request to request an amount change for a budget item in your ministry.
• Select My Requests to view only your own pending requests.
• Table filtering capability for pending changes is supported.

6. View Statistics:

• Select View Statistics from the sidebar.
• Select the year for which you want to view statistics. Years 2019 - 2026 are supported with 2026 as default.
• Select the Budget Results category to view charts related to the overall budget picture. This category includes 4 charts.
• Select the Top Items category to view charts related to the most significant budget items. This category includes 6 charts.
• Select the buttons that appear in the corners of the charts to interact with them.

7. View Change Log History:

• Select View Change History to view the budget change log history.
• Filtering is supported for Change Log table.

8. Managing Pending Changes:

• After logging in exclusively as Prime Minister.
• Select Manage Pending Changes
• Click the Approve button to approve the specific change. Click OK to confirm your selection.
• Click the Reject button to reject the specific change. Click OK to confirm your selection.
• Filtering is supported for Pending Changes table.

Repository Structure

Main Directories

• src/main/java/budget/ - Main application source code

  • backend/ - Backend logic and business layer
    • model/ - Data models and entities
    • service/ - Business logic services
    • repository/ - Data access layer
    • exceptions/ - Custom exception classes
    • util/ - Backend utility classes (validation, password hashing, paths, Regression Analysis)
  • frontend/ - JavaFX GUI
    • controller/ - JavaFX controllers managing user interface interactions and screen navigation
    • util/ - Frontend helper classes (charts, alerts, tables, window management)
  • constants/ - Application constants and messages

• src/test/java/budget/ - Test suite

  • backend/ - Backend unit tests
    • model/ - Tests for domain models and enums
    • service/ - Tests for business logic services
    • repository/ - Tests for data access layer
    • util/ - Tests for utility classes
  • frontend/ - Frontend tests
    • util/ - Tests for UI helper classes
  • constants/ - Tests for application constants

• src/main/resources/ - Application resources

  • view/ - JavaFX layout files
  • images/ - Image assets
  • styles/ - CSS styles
  • users.json - User data storage
  • bill-ministry-map.json - Budget item to ministry mappings
  • budget-changes.json - Approved changes history
  • budget.json - State budget data (2019-2026)
  • pending-changes.json - Pending change requests

• diagram/ - UML diagrams and documentation

  • classDiagram.svg - Class diagram visualization
  • controllersDiagram.svg - Controllers diagram

• pom.xml - Maven project configuration

System Architecture (UML Diagram)

Below is the class diagram that describes the structure of the backend and the organization of the packages.

📂 Diagram Source Code: File preview PlantUML

FrontEnd Controllers Architecture (UML Diagram)

The following is the class diagram for the budget.frontend.controller package.

• The inheritance hierarchy of the Dashboards (Citizen, GovernmentMember, PrimeMinister) derived from the base DashboardController.
• The Navigation Flow from the Login screen to the corresponding application screens.
• The Dependencies, representing which controllers are dynamically loaded within the main Dashboards

📂 Diagram Source Code: View PlantUML file

System Requirements

• Java: Version 21 or latest
• Maven: Version 3.9.6 or latests
• Operating System: Windows, macOS, or Linux

Software Patterns

• Singleton pattern: It is used for uniqueness Prime Minister
• DI (Dependency Injection): It is mainly used in the communication of the Services <-> Repositories
• Repository Design Pattern: For clear separation of data and business logic
• MVC Architecture (Model View Controller): For efficient management of the GUI
• Generic Programming: Type-safe repository interface
  • GenericInterfaceRepository<T, ID> allows flexible entity handling
• Type-Safe Enum Pattern: Enums with additional properties
  • UserRole, Ministry, Status enums with display names and descriptions

Algorithms

Security

• SHA-256: Cryptographic hashing algorithm for secure password storage in users.json
  • Implemented in PasswordUtils.java
  • Provides one-way encryption for user authentication

Data Analysis & Statistics

• Linear Regression: Custom implementation for trend forecasting and budget prediction
  • Implemented in Regression.java
  • Calculates slope and intercept using least squares method
  • Used for predicting future budget trends in statistics charts

Input Validation

• Regular Expressions (Regex): Pattern matching for input validation
  • Username validation: Alphanumeric characters and underscores
  • Password strength: Minimum 8 characters, uppercase, lowercase, digits, special characters
  • Full name validation: Latin characters, proper capitalization
  • UUID format validation
  • Implemented in InputValidator.java

Data Operations

• Filtering & Sorting: Dynamic table data manipulation

  • Used in budget tables, pending changes, and change history views
  • Supports multi-criteria filtering

• Stream Processing: Java 8 Streams for efficient data aggregation

  • Statistical calculations (sum, average, min, max)
  • Budget item grouping by ministry
  • Implemented across service layer

Data Structures

• JSON Parsing: Data serialization/deserialization with Gson library
• ArrayList/List: Sequential storage for entities (budgets, users, pending changes, logs)
• HashMap/Map<K,V>: Key-value pairs for bill-ministry mappings
• ObservableList: JavaFX observable collections for auto-updating UI tables and charts
• FilteredList: Dynamic table filtering with predicates
• Optional: Null-safe wrappers for repository operations
• Stream API: Functional data processing pipelines for filtering, mapping, and aggregation
• XYChart.Series/Data: Time-series structures for statistical charts and regression analysis
• PieChart.Data: Sectional data for budget distribution visualization
• synchronized blocks: Thread-safe access for concurrent file operations

Installation

1. Repository Clone

git clone https://github.com/detandreas/SaveTheGoverment.git
cd SaveTheGoverment

2. Requirements Check

Make sure that you have installed Java 21 and Maven:

java -version    # It should display the version 21
mvn -version     #  It should display the version 3.9.6 or latest

Running the Application

Compile the program.

mvn clean verify # Executes the full build lifecycle:
                 # - Runs all unit tests
                 # - Generates JaCoCo code coverage reports
                 # - Runs Checkstyle code quality checks
                 # - Generates project documentation
                 # - Compiles source files
./mvnw clean verify

Run tests

mvn test
./mvnw test

Method 1: With Maven (It is recommended)

mvn javafx:run # If you have Maven installed on your computer

Method 2: With Maven Wrapper

./mvnw javafx:run    # Linux/macOS
mvnw.cmd javafx:run   # Windows

API / Code Documentation (Javadoc)

The project uses standard Javadoc comments for documenting its public API.

Generate Javadoc

To generate the API documentation, run:

./mvnw javadoc:javadoc

Read API Documentation

open target/site/apidocs/index.html 

Repository statistics

Code Metrics

• Total Lines: 20,696
• Code Lines: 14,874
• Pure Java: 11,025 lines
• java classes 92

Test Coverage

• Backend Coverage: 97%
• Test Classes: 30
• tests run: 382

Github

• Commits: ~800
• Contributors: 8

Contribution

This application was developed as an assignment for the course PROGRAMMING II in the Department of Management Science and Technology in AUEB.

License

This project is licensed under the Apache License 2.0.

📄 See LICENSE for full details or visit the official Apache License page.