PhiloFX: Dining Philosophers

Dinning philosophers problem visualization in Java #JavaFX #JavaScriptingAPI #Nashorn
(This is a rough work-in-progress--see the TODO file.)

After Trois Threads (useless vizualization) and Traffic Sim (web simulation), I think it's time for a more serious simulation in Java.

How to use

Write the philosopher(i) (or philosophe(i)) procedure to solve the dining philosophers problem using semaphores.

From the command line (on Linux!):

java -jar philo.jar PRESET

• Presets:
  • sol0: Mutex, only one philo can eat at a time.
  • sol1: Sem for each fork, deadlocks are possible (written in French)
  • sol2: Sem for each philo, philosophers wake one another to eat
  • sol3: The last philo is left-handed
  • sol4: Only N - 1 philos can attempt to acquire forks at any given time

* These are read from the presets folder in the current working directory.

Predefined functions

• N is the total number of philosophers

• think() or penser(): Lasts for 5-10 seconds, refills philosopher's "health".

• eat() or manger(): Lasts for 5-10 seconds

• takeFork(i) or prendreFourchette(i): Actually take the fork!

• putFork(i) or poserFourchette(i): Actually put the fork down!

• Sem(n): Same as new Semaphore(n, true)

• p(sem): Same as sem.acquire()

• v(sem): Same as sem.release()

How it works

...

Nashorn to execute user code

Java

• JavaScript's setTimeout/setInterval counterpart in Java: Timer and TimerTask.

• Visualizing using SVG by updating it through the Document interface via JavaFX's WebEngine.

Notes

• Alternative scripting engine: Mozilla's Rheno

References and Good Reads

• Oracle's Java Scripting Programmer's Guide
• Andrew S. Tanenbaum - Modern Operating Systems 4th ed.

Credits and Thanks

• The "animation" is partially inspired by Simon Ingeson's Hungry Thinkers.

• The logo is composed from

  • Chopsticks by Peter Emil van den Berg, NL
  • Philosopher's stone by Locad, GB

License

By @djalilhebal and @wanisramdani, under CC BY 3.0