🚗 Car Wash Simulation

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📖 Overview

This project is a Java 25 simulation of a Car Wash and Gas Station, built to model the Producer–Consumer Problem using custom semaphores and mutexes.
It demonstrates synchronization and safe concurrent access to shared resources in multithreaded environments.

• Cars (Producers) continuously arrive seeking service.
• Pumps (Consumers) represent service bays working in parallel.
• Synchronization ensures cars wait when the queue is full and pumps operate only when cars are available.

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🧩 Repository Structure

Car-Wash-Simulation/
│
├── GUI/
│   └── ServiceStation.java        # JavaFX 25 GUI version with animations
│
├── GUI_TXT/
│   └── ServiceStation.java        # JavaFX 25 GUI version (text-based, no animations)
│
├── src/
│   └── ServiceStation.java        # Console version (terminal-based)
│
├── .gitignore
└── README.md

🧠 Note:
Each version includes only one file named ServiceStation.java (as required by the assignment).
All synchronization logic (Semaphores, Cars, Pumps) is contained in that file.

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🧠 Concept & Objective

The project applies Operating-Systems synchronization principles—particularly the Bounded Buffer pattern—to simulate limited waiting space and concurrent servicing.

It ensures:

• Cars cannot enter a full waiting area.
• Pumps only serve cars when available.
• Only one thread modifies the queue at a time.
• The number of serviced cars never exceeds the number of pumps.

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⚙️ Implementation Details

🧱 ServiceStation (Main Controller)

Initializes shared resources (Queue, Mutex, Empty, Full, Pumps semaphores), reads user input, and launches producer and consumer threads.

🚗 Car (Producer)

• Represents an arriving car.
• Waits if the queue is full (Empty.wait()).
• Adds itself safely under mutex protection.
• Signals a pump that a car is available (Full.signal()).

⛽ Pump (Consumer)

• Waits for available cars (Full.wait()) and bays (Pumps.wait()).
• Removes a car, services it, and releases the bay.

🔒 Semaphore

Custom counting semaphore with wait() (P) and signal() (V), preventing race conditions and ensuring proper synchronization.

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🖥️ Versions & Execution

🧾 Console Version — src/ServiceStation.java

Run from terminal:

cd src
javac ServiceStation.java
java ServiceStation

Example Input

Enter waiting area capacity: 5
Enter number of service bays: 3

Example Output

C1 arrived
C2 arrived
C3 arrived
Pump 1: C1 occupied
Pump 2: C2 occupied
Pump 3: C3 occupied
C4 arrived and waiting
C5 arrived and waiting
Pump 1: C1 finishes service
Pump 1: Bay 1 is now free
Pump 1: C4 begins service
Pump 2: C5 begins service
All cars processed; simulation ends

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🎨 GUI Version — GUI/ServiceStation.java

• JavaFX 25 animated version showing cars moving between waiting areas and pumps.
• Real-time visual updates for car movement and pump usage.

Run

1. Open the folder in VS Code or IntelliJ with JavaFX configured.
2. Run ServiceStation.java inside the GUI folder.

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💬 Text-Based GUI Version — GUI_TXT/ServiceStation.java

• Simplified JavaFX 25 version with textual logs only (no animations).
• Useful for lightweight visualization.

Run

1. Open in your IDE with JavaFX configured.
2. Run ServiceStation.java inside the GUI_TXT folder.

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🧭 Getting Started — JavaFX 25 Setup in VS Code

🪜 Step 1: Install Required Extensions

1. Open VS Code.
2. Go to Extensions (Ctrl + Shift + X).
3. Install:
   • ✅ Extension Pack for Java (Microsoft)
   • ✅ Optional: JavaFX Support

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🪜 Step 2: Download JavaFX 25 SDK

1. Visit https://openjfx.io.
2. Download JavaFX 25 SDK for your OS.
3. Extract it, e.g.:

   C:\javafx-sdk-25\
   

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🪜 Step 3: Configure VS Code Launch Settings

Add VM arguments to include JavaFX libraries.

For Windows

--module-path "C:\javafx-sdk-25\lib" --add-modules javafx.controls,javafx.fxml

For macOS/Linux

--module-path "/path/to/javafx-sdk-25/lib" --add-modules javafx.controls,javafx.fxml

Example .vscode/launch.json

{
  "configurations": [
    {
      "type": "java",
      "name": "Run GUI (JavaFX 25)",
      "request": "launch",
      "mainClass": "ServiceStation",
      "vmArgs": "--module-path \"C:\\javafx-sdk-25\\lib\" --add-modules javafx.controls,javafx.fxml"
    }
  ]
}

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🪜 Step 4: Run

• Open GUI/ServiceStation.java or GUI_TXT/ServiceStation.java.
• Click Run ▶️ in VS Code.
• The JavaFX 25 window will launch showing the simulation.

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🧰 Technologies Used

• Java 25
• JavaFX 25
• Multithreading & Concurrency
• Custom Semaphores & Mutexes
• Producer–Consumer (Bounded Buffer)

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🧑‍💻 Contributors

Name	Student ID
Ali Radwan Farouk	20231110
Adel Hefny	20230198
Mohamed Mahmoud	20230354
Asser Ahmed	20230655

Section: AI S5
Course: CS241 – Operating Systems 1
Faculty: Computers and Artificial Intelligence, Cairo University

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🏁 Acknowledgements

Developed for CS241 Operating Systems (Synchronization Assignment) under TA Mena Asfour.
Demonstrates thread synchronization and bounded-buffer concurrency using Java 25 and JavaFX 25.