Soccorritori Java

gistfile1.java

import java.util.ArrayList;
import java.util.List;

public class Soccorritori {
	private static final int NUM = 4; // Numero soccorritori.
	private static final int C = 3; // Capienza elicottero.

	public static final int IDLE = 0;
	public static final int SETTING = 1;
	public static final int READY = 2;
	public static final int BACK = 3;

	public static void log(String text) {
		System.out.println(Thread.currentThread().getName() + ": " + text);
	}

	public class Capo {
		private int _state = IDLE;
		private Elicottero _elicottero;

		public Capo(Elicottero elicottero) {
			this._elicottero = elicottero;
		}

		public synchronized void saliPilota(Pilota pilota) {
			// Il pilota sale
			while (_state != IDLE) {
				try {
					wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

			log("Pilota salito a bordo.");
			_state = SETTING;
			notifyAll();
		}

		public synchronized void iniziaMissione() {
			while (_state != READY) {
				try {
					log("Pilota attende che l'elicottero sia pieno.");
					wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

			log("Missione iniziata.");
			notifyAll();
		}

		public synchronized void terminaMissione() {
			long time = (long) (Math.random() * 10000);

			try {
				Thread.sleep(time);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

			_state = BACK;
			log("Missione durata " + time + " millis");
			notifyAll();
		}

		public synchronized void saliBordo(Soccorritore soccorritore) {
			while (_state != SETTING || _elicottero.isPieno()) {
				try {
					log("Soccorritore in attesa.");
					wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

			// Fai salire il soccorritore sull'elicottero.
			_elicottero.getSoccorritori().add(soccorritore);
			log("Soccorritore salito a bordo.");

			if (_elicottero.isPieno()) {
				_state = READY;
			}

			// Notifica agli altri thread.
			notifyAll();
		}

		public synchronized void scendi(Soccorritore soccorritore) {
			while (_state != BACK) {
				try {
					log("Soccorritore in missione.");
					wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

			_elicottero.getSoccorritori().remove(soccorritore);
			log("Soccorritore sceso.");

			if (_elicottero.isVuoto())
				_state = IDLE;

			notifyAll();
		}

	}

	public class Pilota implements Runnable {
		private final Capo _capo;

		public Pilota(Capo capo) {
			this._capo = capo;
		}

		@Override
		public void run() {
			while (true) {
				try {
					Thread.sleep((long) (Math.random() * 5000));
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}

				// Ricevuto allarme.
				_capo.saliPilota(this);
				_capo.iniziaMissione();
				_capo.terminaMissione();
			}

		}
	}

	public class Elicottero {
		private boolean _partito;
		private final int _max;
		private boolean _pilota = false;

		private List<Soccorritore> _soccorritori;

		public Elicottero(int max) {
			// TODO Auto-generated constructor stub
			this._max = max;
			this._soccorritori = new ArrayList<Soccorritori.Soccorritore>();
		}

		public boolean isPieno() {
			return this._max == _soccorritori.size();
		}

		public boolean isVuoto() {
			return _soccorritori.size() == 0;
		}

		public List<Soccorritore> getSoccorritori() {
			return _soccorritori;
		}

		public int getMax() {
			return _max;
		}

		public boolean partito() {
			return _partito;
		}

		public boolean pilotaBordo() {
			return _pilota;
		}

		public void pilotaSali() {
			_pilota = true;
		}

		public void pilotaScendi() {
			_pilota = false;
		}

		public void iniziaMissione() {
			_partito = true;
		}

		public void terminaMissione() {
			_partito = false;
		}
	}

	public class Soccorritore implements Runnable {
		private final Capo _capo;

		public Soccorritore(Capo capo) {
			this._capo = capo;
		}

		@Override
		public void run() {
			while (true) {
				this._capo.saliBordo(this);
				this._capo.scendi(this);

				try {
					Thread.sleep((long) (Math.random() * 1000));
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}

	public Soccorritori() {

		Elicottero elicottero = new Elicottero(C);
		Capo capo = new Capo(elicottero);

		for (int i = 0; i < NUM; i++) {
			Thread thread = new Thread(new Soccorritore(capo));
			thread.setName("Soccorritore " + i);
			thread.start();
		}

		Thread pilota = new Thread(new Pilota(capo));
		pilota.setName("Pilota");
		pilota.start();
	}

	public static void main(String[] args) {
		new Soccorritori();
	}

}