🧪 S‑Emulator – Multi‑Stage Java Project

A full Java ecosystem built around the minimalist S language: from a core emulator, through rich JavaFX tools, to a multi‑user server and modern Web client.

---

📖 Overview

This repository contains four main stages (course exercises), each adding a new architectural layer on top of the previous one. The project simulates an execution environment for the S Language, evolving from a console application to a distributed web system.

---

📂 Repository Structure & Stages

🔹 Stage 1: Engine & Console (exercise1-engine-console)

Core S Emulator & Console Interface

Implements the execution engine including variables, labels, program model, and flow control.

• Core Logic: XML programs are parsed, validated, and translated into instruction objects (Increase, Decrease, Jumps, Assignments, Quote, etc.).
• Console UI: Wraps the engine to expose operations: load, display, expand, execute, and statistics.

---

🔹 Stage 2: Desktop GUI (exercise2-javafx)

JavaFX GUI & Local Debugger

Builds a visual layer on top of the core engine to make S programs interactive.

• MVC Architecture: Controllers (AppController, InstructionsController, DebuggerExecutionController) coordinate the view and logic.
• Features:
  • Step‑by‑step debugging & breakpoints.
  • Instruction highlighting.
  • Theming via ThemeManager & animations via AnimationManager.

📸 Screenshots (Click to expand)

• 
• 
• 

---

🔹 Stage 3: Multi‑User Server (exercise3-server-client)

Servlet Backend & Remote JavaFX Client

Transforms the emulator into a multi-user system where users can log in, upload programs, and debug remotely.

Server Side (Java Servlets)

• Managers: UserManager, ExecutionSessionManager, ProgramManager.
• Endpoints: LoginServlet, UploadServlet, ExecuteServlet, DebugServlet.
• Infrastructure: Uses ServletUtils and CORSFilter for shared context and access control.

Client Side (JavaFX)

• UI Components: DashboardController, ExecuteScreenController, LoginController.
• Networking: Uses a DTO layer (UserData, LoginResponse, ProgramDTO) to communicate with the server.

📸 Screenshots (Click to expand)

• 
• 
• 

---

🔹 Stage 4: Web Client (exercise4-webclient)

React + Vite Frontend

A modern Single Page Application (SPA) consuming the existing HTTP API.

• Tech Stack: React, Vite (main.jsx, App.jsx).
• Key Screens:
  • LoginScreen.jsx – User bootstrap.
  • DashboardScreen.jsx – Program management.
  • ExecutionScreen.jsx – Live execution visualization.
• Integration: HttpClientUtil and CookieManager handle API calls and session persistence.

📸 Screenshots (Click to expand)

• 
• 
• 

---

🧱 Core Concepts

Across all exercises, the following architectural principles are maintained:

1. Single Core Engine: All clients (Console, JavaFX Desktop, Web) share the exact same instruction set and execution pipeline.
2. Synthetic vs. Base Instructions: High-level constructs (macros) are compiled down to a minimal base instruction set.
3. DTO‑Driven APIs: Internal models remain encapsulated. External communication happens strictly via Data Transfer Objects (DTOs).
4. Observability: Execution history, statistics, and credit usage are explicitly tracked for debugging and analysis.

---