Q4. TCP/IP done

README.md

@@ -0,0 +1,5 @@
+# PROJET IFT630 STS 2
+Ce projet utilise maven.
+Un test est utilisé pour voir le projet fonctionner.
+Pour l'executer, vous pouvez faire `mvn test` dans la racine.
+Les questions sont répondues avec les commits correspondant.

src/main/java/usherbrooke/ift630/App.java

@@ -1,132 +1,46 @@
 package usherbrooke.ift630;
 
-import java.lang.Long;
-import java.util.ArrayList;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.LinkedBlockingQueue;
-
 public class App {
-	static private int numBusPerTrip		= 1;
+	static private int numLines				= 3;
-	static private int numTrips				= 1;
+	static private int numBusPerLine		= 2;
-	static private int numBusses			= numTrips * numBusPerTrip;
+	static private int numBusses			= numLines * numBusPerLine;
 	static private int numStopPerBus		= 8;
 	static private int numStops				= numBusses * numStopPerBus;
-	static private int numPassengersPerBus	= 10;
+	static private int numPassengersPerBus	= 5;
 	static private int numPassengersPerStop = 5;
 	//static private int numPassengers		= numPassengersPerStop * numStops;
 	static private int numThreadsBus		= 5;
 	static private int numThreadsStop		= 2;
 	static private int timeBetweenStops 	= 5;
 	static private int timeEmbark			= 2;
+	static private int socketPort			= 8181;
 
 	public static void main(String[] args) {
-		ExecutorService threadsBus = Executors.newFixedThreadPool(numThreadsBus);
+		try {
-		ExecutorService threadsStop = Executors.newFixedThreadPool(numThreadsStop);
+			if (numStopPerBus > numStops) {
-		ExecutorService threadsPassenger = Executors.newFixedThreadPool(1); // doesnt need more! future balance
+				System.out.println("More stops per bus than stops.");
-																			// themselfes out.
+				return;
-		ArrayList<Stop> stops = new ArrayList<Stop>();
-		ArrayList<Bus> busses = new ArrayList<Bus>();
-		ArrayList<Trip> trips = new ArrayList<Trip>();
-		ArrayList<Passenger> passengers = new ArrayList<Passenger>();
-		BlockingQueue<BusInformationMessage> blockingQueue = new LinkedBlockingQueue<BusInformationMessage>();
-
-		if (numStopPerBus > numStops) {
-			System.out.println("More stops per bus than stops.");
-			return;
-		}
-
-		// make stop" + name + " reached stop " + nextStop.getStopName() + "!"s
-		for (int k = 0; k < numStops; k++) {
-			Stop s = new Stop(k, numPassengersPerStop);
-			s.setBlockingQueue(blockingQueue);
-
-			stops.add(s);
-			s.setThreadPool(threadsStop);
-			threadsStop.submit(s);
-		}
-
-		// make trpis
-		for (int k = 0 ; k < numTrips ; k++) {
-			Stop s;
-			ArrayList<Stop> s_list = new ArrayList<Stop>();
-			while (s_list.size() < numStopPerBus) {
-				do {
-					s = stops.get((int) (Math.random() * numStops));
-				} while (s_list.contains(s));
-				s_list.add(s);
 			}
 
-			Trip t = new Trip(k, s_list);
+			Central central = new Central(numThreadsBus, numThreadsStop, socketPort);
-			trips.add(t);
+			// create everything
+			central.createStops(numStops, numPassengersPerStop);
+			central.createLines(numLines, numStopPerBus, numStops);
+			central.createBusses(numBusses, timeBetweenStops, timeEmbark, numPassengersPerBus);
+			central.createPassengers(numPassengersPerStop, numStopPerBus);
+
+			// print start details
+			System.out.println("-----".repeat(5) + " START " + "-----".repeat(5));
+			central.printDetails();
+			System.out.println("-----".repeat(5) + " START " + "-----".repeat(5));
+
+			// start bus thread
+			central.startBusThreads();
+
+			// shutdown and wait!
+			central.shutdown();
+		} catch (Exception e) {
+			System.out.println("[APP] " + e.toString());
 		}
-
-		// make busses
-		for (int k = 0; k < numBusses; k++) {
-			Bus b = new Bus(trips.get(k % trips.size()), k, timeBetweenStops, timeEmbark, numPassengersPerBus);
-			b.setBlockingQueue(blockingQueue);
-
-			busses.add(b);
-		}
-
-		// make passenger
-		int idPassenger = 0;
-		for (Bus b : busses) {
-			for (Stop start : b.getStops()) {
-
-				// make sure passenger can leave.
-				if (start == b.getTerminus())
-					continue;
-
-				int idx = b.getStops().indexOf(start);
-				if (idx == -1 || start == b.getTerminus())
-					continue;
-
-				for (int k = 0; k < (int) (Math.random() * numPassengersPerStop); k++) {
-					Stop dest = null;
-
-					dest = b.getStops().get(idx + 1 + (int) Math.round(Math.random() * (numStopPerBus - 2 - idx)));
-
-					Passenger p = new Passenger(idPassenger, start, dest);
-					passengers.add(p);
-					start.addPassenger(p);
-					idPassenger++;
-
-					threadsPassenger.submit(p);
-				}
-			}
-		}
-
-		// pretty print!
-		for (Bus b : busses) {
-			b.printDetails();
-		}
-
-		System.out.println("-----".repeat(5) + " START " + "-----".repeat(5));
-
-		// start bus thread
-		// (here so init logs are clean)
-		for (Bus b : busses) {
-			threadsBus.submit(b);
-		}
-
-		// block bus pool
-		threadsBus.shutdown();
-		try {
-			threadsBus.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
-		} catch (InterruptedException e) {}
-
-		// block stop and passenger pool once bus have finished
-		threadsStop.shutdown();
-		threadsPassenger.shutdown();
-		try {
-			threadsStop.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
-		} catch (InterruptedException e) {}
-
-		try {
-			threadsPassenger.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
-		} catch (InterruptedException e) {}
 	}
 }

src/main/java/usherbrooke/ift630/Bus.java

@@ -1,12 +1,16 @@
 package usherbrooke.ift630;
 
+import java.net.Socket;
+import java.io.IOException;
+import java.io.PrintWriter;
+
 import java.util.List;
 import java.util.ArrayList;
 import java.util.concurrent.BlockingQueue;
 
 public class Bus extends Thread {
 	private ArrayList<Passenger> passengers;
-	private Trip trip;
+	private Line line;
 	private String name;
 	private int id;
 	private int maxCapacity;
@@ -15,8 +19,11 @@ public class Bus extends Thread {
 	private int timeToNextStop;
 	private int timeEmbark;
 	private int nextStopIndex = 0;
+	private int socketPort;
 	private Stop nextStop;
 	private BlockingQueue<BusInformationMessage> blockingQueue;
+	private Socket socket;
+	private PrintWriter socketTx;
 
 	// returns time for a single passenger to embark.
 	private int timeEmbark() {
@@ -25,7 +32,7 @@ public class Bus extends Thread {
 
 	// set time between stop.
 	private int calculateTimeBetweenStops() {
-		timeToNextStop = (int) ((timeBetweenStops / 3) + (Math.random() * 2 * timeBetweenStops / 3));
+		timeToNextStop = (int) ((timeBetweenStops / 3f) + (Math.random() * 2f * timeBetweenStops / 3f));
 		return timeToNextStop;
 	}
 
@@ -35,7 +42,6 @@ public class Bus extends Thread {
 		for (Passenger p : passengers) {
 			if (p.getDest() == nextStop) {
 				res = true;
-				Logger.getInstance().print(id, "[BUS] " + name + " stop asked!");
 				break;
 			}
 		}
@@ -44,11 +50,12 @@ public class Bus extends Thread {
 	}
 
 	// travel to next stop. Waits the travel time.
-	private Stop goToNextStop() throws InterruptedException, IndexOutOfBoundsException {
+	private Stop goToNextStop() throws InterruptedException, IndexOutOfBoundsException, IOException {
 		// if no reason to stop, skip current stop
 		boolean nextStopEmpty, overMaxCapacity;
 		do {
-			nextStop = trip.get(++nextStopIndex);
+			nextStopIndex += 1;
+			nextStop = line.get(nextStopIndex);
 
 			sendNextStopInfo();
 
@@ -57,8 +64,12 @@ public class Bus extends Thread {
 			overMaxCapacity = currentCapacity >= maxCapacity;
 			nextStopEmpty = getNextStopPassengers().isEmpty();
 
-			if (overMaxCapacity)
+			if (stopAsked()) 
+				Logger.getInstance().print(id, "[BUS] " + name + " stop asked!");
+			if (overMaxCapacity) {
 				Logger.getInstance().print(id, "[BUS] " + name + " im full, sorry!");
+				sendFulLMessage();
+			}
 			if (nextStopEmpty && !stopAsked())
 				Logger.getInstance().print(id, "[BUS] " + name + " next " + nextStop.getStopName() + " is empty!");
 		} while (!stopAsked() && (nextStopEmpty || overMaxCapacity));
@@ -80,20 +91,29 @@ public class Bus extends Thread {
 		ArrayList<Passenger> res = new ArrayList<Passenger>();
 
 		if (nextStop != null)
-			res = nextStop.getPassengerByDest(trip, nextStopIndex);
+			res = nextStop.getPassengerByDest(line, nextStopIndex);
 		return res;
 	}
 
 	// lock until passenger got in
-	private synchronized void waitEmbark() throws InterruptedException {
+	private void waitEmbark() throws InterruptedException {
 		sleep(timeEmbark());
 	}
 
 	// lock until passenger got out
 	private void waitStop() throws InterruptedException {
-		synchronized (this) {
+		sleep(timeToNextStop);
-			sleep(timeToNextStop);
+	}
-		}
+
+	private void connectSocket() throws IOException {
+		socket = new Socket("localhost", socketPort);
+		socketTx = new PrintWriter(socket.getOutputStream(), true);
+	}
+
+	private void sendFulLMessage() throws IOException {
+		connectSocket();
+		socketTx.println("FULL:" + id);
+		socket.close();
 	}
 
 	@Override
@@ -102,8 +122,8 @@ public class Bus extends Thread {
 			// run until terminus
 			while (nextStop != null) {
 				// new stop !
-				Logger.getInstance().print(id, "[BUS] " + name + " reached stop " + nextStop.getStopName() + "!");
 
+				Logger.getInstance().print(id, "[BUS] " + name + " reached stop " + nextStop.getStopName() + "!");
 				disembarkPassengers();
 				embarkPassengers();
 				calculateTimeBetweenStops();
@@ -120,14 +140,14 @@ public class Bus extends Thread {
 		Logger.getInstance().print(id, "[BUS] " + name + " exiting!");
 	}
 
-	Bus(Trip trajet, int id, int timeStop, int timeEmbark, int maxCapacity) {
+	Bus(Line line, int id, int timeStop, int timeEmbark, int maxCapacity) {
 		this.timeBetweenStops	= timeStop * 1000 + 1;
 		this.timeEmbark			= timeEmbark * 1000 + 1;
 		this.name				= "Bus n°" + id;
 		this.id					= id;
 		this.passengers			= new ArrayList<Passenger>();
-		this.trip				= trajet;
+		this.line				= line;
-		this.nextStop			= trajet.get(0);
+		this.nextStop			= line.get(0);
 		this.currentCapacity	= 0;
 		this.maxCapacity		= maxCapacity;
 	}
@@ -151,10 +171,10 @@ public class Bus extends Thread {
 
 	// embark passenger at a stop. Synchronizes, locks on that stop, and waits.
 	// check for overflow, and if passenger should embark in the first place
-	public synchronized void embarkPassengers() throws InterruptedException {
+	public synchronized void embarkPassengers() throws InterruptedException, IOException {
 		synchronized (nextStop) {
 			try {
-				ArrayList<Passenger> list = nextStop.getPassengerByDest(trip, nextStopIndex);
+				ArrayList<Passenger> list = nextStop.getPassengerByDest(line, nextStopIndex);
 				for (Passenger p : list) {
 					waitEmbark();
 					if (currentCapacity >= maxCapacity)
@@ -178,9 +198,9 @@ public class Bus extends Thread {
 		Logger.getInstance().print(id, "\t".repeat(indent) + "current stop: " + nextStop.getStopName());
 		Logger.getInstance().print(id, "\t".repeat(indent) + "stops: ");
 
-		if (nextStop != trip.get(0))
+		if (nextStop != line.get(0))
 			nextStop.printDetails(id, indent + 1);
-		for (Stop s : trip.getStops()) {
+		for (Stop s : line.getStops()) {
 			s.printDetails(id, indent + 1);
 		}
 	}
@@ -192,18 +212,27 @@ public class Bus extends Thread {
 
 	// return last stop
 	public Stop getTerminus() {
-		return trip.getTerminus();
+		return line.getTerminus();
 	}
 
 	public String getNameBus() {
 		return name;
 	}
 
+	// still there since i first didnt understand what a trip should have been. See git logs.
 	public List<Stop> getStops() {
-		return trip.getStops();
+		return line.getStops();
 	}
 
 	public void setBlockingQueue(BlockingQueue<BusInformationMessage> q) {
 		blockingQueue = q;
 	}
+
+	public void setSocketPort(int port) {
+		socketPort = port;
+	}
+
+	public Line getLine() {
+		return line;
+	}
 }

src/main/java/usherbrooke/ift630/Central.java

@@ -0,0 +1,242 @@
+package usherbrooke.ift630;
+
+import java.io.IOException;
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+
+import java.net.Socket;
+import java.net.ServerSocket;
+
+import java.util.ArrayList;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.Executors;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
+
+class Central {
+	private ExecutorService threadsBus;
+	private ExecutorService threadsSpareBusses;
+	private ExecutorService threadsStop;
+	private ExecutorService threadsPassenger;
+	private ExecutorService threadsSocket;
+	private ArrayList<Stop> stops;
+	private ArrayList<Bus> busses;
+	private ArrayList<Line> lines;
+	private ArrayList<Passenger> passengers;
+	private BlockingQueue<BusInformationMessage> blockingQueue;
+	private ServerSocket socket;
+	private Future<Void> socketFuture;
+	private int socketPort;
+	private boolean socketStop = false;
+
+	private int timeEmbark;
+	private int timeBetweenStops;
+	private int numPassengersPerBus;
+
+	// idk what to do with those
+	private ArrayList<Integer> spacePerStop;
+	private ArrayList<Integer> spacePerLine;
+
+	private void sendBus(String msg) {
+		Bus reqB = busses.get(Integer.parseInt(msg));
+		Line l = reqB.getLine();
+		// if >= 2 bus are full on that line, reset counter and add a bus
+		if (spacePerLine.get(l.getId()) >= 2) {
+			Bus b = new Bus(l, busses.size(), timeBetweenStops, timeEmbark, numPassengersPerBus);
+			b.setSocketPort(socketPort);
+			b.setBlockingQueue(blockingQueue);
+
+			busses.add(b);
+
+			threadsSpareBusses.submit(b);
+
+			Logger.getInstance().print(0, "\t[CENTRAL] Sent a new bus on line " + l.getName());
+		}
+	}
+
+	// should be used to see what lines need more bus and act accordingly.
+	// This is hard to do w/ our implementation, since we cannot see what passenger
+	// will embark on what line trivialy.
+	// Therefore, when a bus is full, a new one will go get remaining passengers.
+	private void refreshStops(String stop, String number) {
+		int s = Integer.parseInt(stop);
+		int n = Integer.parseInt(number);
+		int l = 0;
+		for (int k = 0 ; k < lines.size() ; k ++) {
+			if (lines.get(k).getStops().contains(stops.get(s))) {
+				l = k;
+			}
+		}
+		
+		spacePerStop.set(s, n);
+		spacePerLine.set(l, spacePerLine.get(l) + 1);
+		Logger.getInstance().print(0, "\t[CENTRAL] refreshed stop value for " + stops.get(s).getStopName());
+	}
+
+	// run TCP socket until an exception occurs
+	private void runSocket() {
+		if (socketFuture == null)
+			// use a thread, so we dont block here
+			threadsSocket.submit(() -> {
+				try {
+					while (!socketStop) {
+						// blocks until client connects
+						String txt;
+						Socket s = socket.accept();
+
+						BufferedReader rx = new BufferedReader(new InputStreamReader(s.getInputStream()));
+						txt = rx.readLine();
+
+						// split on ':'
+						// 0 => who
+						// 1 => id
+						// 2 => arg if necessary
+						String[] msg = txt.split(":");
+
+						if (msg[0].startsWith("FULL"))
+							sendBus(msg[1]);
+						else if (msg[0].startsWith("STOP")) {
+							refreshStops(msg[1], msg[2]);
+						}
+
+						// loop back to accept 
+						s.close();
+					}
+				} catch (Exception e) {Logger.getInstance().print(1, "[CENTRAL] exc " + e.getMessage()); e.printStackTrace();}
+			});
+	}
+
+	Central (int numThreadsBus, int numThreadsStop, int socketPort) throws IOException{
+		threadsBus = Executors.newFixedThreadPool(numThreadsBus);
+		threadsSpareBusses = Executors.newFixedThreadPool(numThreadsBus);
+		threadsStop = Executors.newFixedThreadPool(numThreadsStop);
+		threadsPassenger = Executors.newSingleThreadExecutor(); // doesnt need more! future balances themselves.
+		threadsSocket = Executors.newSingleThreadExecutor();
+		stops = new ArrayList<Stop>();
+		busses = new ArrayList<Bus>();
+		lines = new ArrayList<Line>();
+		passengers = new ArrayList<Passenger>();
+		spacePerStop = new ArrayList<Integer>();
+		spacePerLine = new ArrayList<Integer>();
+		blockingQueue = new LinkedBlockingQueue<BusInformationMessage>(); 
+
+		this.socketPort = socketPort;
+		socket = new ServerSocket(socketPort);
+		runSocket();
+	}
+
+	// init stops
+	public void createStops(int numStops, int numPassengersPerStop) {
+		for (int k = 0; k < numStops; k++) {
+			Stop s = new Stop(k, numPassengersPerStop);
+			s.setBlockingQueue(blockingQueue);
+			s.setSocketPort(socketPort);
+
+			stops.add(s);
+			s.setThreadPool(threadsStop);
+			threadsStop.submit(s);
+		}
+
+		for (int k = 0 ; k < stops.size() ; k++)
+			spacePerStop.add(k, 0);
+	}
+
+	// init lines (need stops to be init before)
+	public void createLines(int numLines, int numStopPerBus, int numStops) throws Exception {
+		for (int k = 0 ; k < numLines ; k++) {
+			Stop s;
+			if (numStopPerBus > stops.size()) 
+				throw new Exception("not enough stops");
+			ArrayList<Stop> s_list = new ArrayList<Stop>();
+			while (s_list.size() < numStopPerBus) {
+				do {
+					s = stops.get((int) (Math.random() * numStops));
+				} while (s_list.contains(s));
+				s_list.add(s);
+			}
+
+			Line l = new Line(k, s_list);
+			lines.add(l);
+		}
+
+		for (int k = 0 ; k < lines.size() ; k++)
+			spacePerLine.add(k, 0);
+	}
+
+	// init busses
+	public void createBusses(int numBusses, int timeBetweenStops, int timeEmbark, int numPassengersPerBus) throws IOException{
+		this.numPassengersPerBus = numPassengersPerBus;
+		this.timeBetweenStops = timeBetweenStops;
+		for (int k = 0; k < numBusses; k++) {
+			Line l = lines.get(k % lines.size());
+			Bus b = new Bus(l, k, timeBetweenStops, timeEmbark, numPassengersPerBus);
+			b.setSocketPort(socketPort);
+			b.setBlockingQueue(blockingQueue);
+
+			busses.add(b);
+		}
+	}
+
+	// init pasengers
+	public void createPassengers(int numPassengersPerStop, int numStopPerBus) {
+	// make passenger
+		int idPassenger = 0;
+		for (Bus b : busses) {
+			for (Stop start : b.getStops()) {
+				// if not found or is terminus, dont use
+				int idx = b.getStops().indexOf(start);
+				if (idx == -1 || start == b.getTerminus())
+					continue;
+
+				// rand number of passenger per stop
+				for (int k = 0; k < (int) (Math.random() * numPassengersPerStop); k++) {
+					Stop dest = null;
+					// dest is random from list of stops of this line
+
+					dest = b.getStops().get(idx + 1 + (int) Math.round(Math.random() * (numStopPerBus - 2 - idx)));
+
+					// create them!
+					Passenger p = new Passenger(idPassenger, start, dest);
+					passengers.add(p);
+					start.addPassenger(p);
+					idPassenger++;
+
+					threadsPassenger.submit(p);
+				}
+			}
+		}
+	}
+
+	// pretty print!
+	public void printDetails() {
+		for (Bus b : busses) {
+			b.printDetails();
+		}
+	}
+
+	// start bus thread
+	public void startBusThreads() {
+		for (Bus b : busses)
+			threadsBus.submit(b);
+	}
+
+	// shutdowns all threand & return.
+	public void shutdown() {
+		// block stop and passenger pool once bus have finished
+		try {
+			threadsBus.shutdown();
+			threadsBus.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
+			threadsSpareBusses.shutdown();
+			threadsSpareBusses.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
+			threadsStop.shutdown();
+			threadsStop.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
+			threadsPassenger.shutdown();
+			threadsPassenger.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
+			socketStop = true;
+			//threadsSocket.shutdown();
+			//threadsSocket.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
+		} catch (InterruptedException e) {}
+	}
+}

src/main/java/usherbrooke/ift630/Line.java

@@ -1,19 +1,20 @@
 package usherbrooke.ift630;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.ArrayList;
 
-class Trip {
+class Line {
 	private List<Stop> stops;
 	private String name;
 	private int id;
 
-	Trip(int id, ArrayList<Stop> stops) {
+	Line(int id, ArrayList<Stop> stops) {
 		this.id = id;
-		this.name = "Trip " + this.id;
+		this.name = "Line " + this.id;
 		this.stops = stops;
 	}
 
+	// get stops from index
 	public List<Stop> getStops(int index) {
 		return stops.subList(index, stops.size() - 1);
 	}
@@ -41,6 +42,10 @@ class Trip {
 		return stops.get(idx);
 	}
 
+	public int getId() {
+		return id;
+	}
+
 	public Stop getTerminus() {
 		return stops.get(stops.size() - 1);
 	}

src/main/java/usherbrooke/ift630/Passenger.java

@@ -30,7 +30,7 @@ public class Passenger extends Thread {
 	}
 
 	// embark people once thread notified
-	private synchronized Future<Void> embark() {
+	private Future<Void> embark() {
 		return ex.submit(() -> {
 			synchronized (this) {
 				wait();
@@ -41,7 +41,7 @@ public class Passenger extends Thread {
 	}
 
 	// disembark people once thread notified another time.
-	private synchronized Future<Void> disembark() {
+	private Future<Void> disembark() {
 		return ex.submit(() -> {
 			synchronized (this) {
 				wait();

src/main/java/usherbrooke/ift630/Stop.java

@@ -1,5 +1,9 @@
 package usherbrooke.ift630;
 
+import java.net.Socket;
+import java.io.IOException;
+import java.io.PrintWriter;
+
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutorService;
 import java.util.ArrayList;
@@ -9,9 +13,27 @@ public class Stop extends Thread {
 	private int id;
 	private int maxCapacity;
 	private int indent = 0;
+	private int socketPort;
 	private ArrayList<Passenger> passengers;
 	private ExecutorService threads;
 	private BlockingQueue<BusInformationMessage> blockingQueue;
+	private Socket socket;
+	private PrintWriter socketTx;
+
+
+	private void connectSocket() throws IOException {
+		socket = new Socket("localhost", socketPort);
+		socketTx = new PrintWriter(socket.getOutputStream(), true);
+	}
+
+	// 
+	private void sendCurrentCapacity() throws IOException {
+		connectSocket();
+		// prone to over estimation. Some passenger will take other lines.
+		// One again, i did not understand lines before last question. see git logs.
+		socketTx.println("STOP:" + id + ":" + passengers.size());
+		socket.close();
+	}
 
 	// print bus info times.
 	private void displayInfos(int indent) throws InterruptedException, ExitException {
@@ -29,8 +51,7 @@ public class Stop extends Thread {
 				Logger.getInstance().print(id,
 						"\t".repeat(indent) + "[STOP] " + info.getBus(this).getNameBus() + " arrives in " + time + "s");
 				// else, catch
-			} catch (NullPointerException e) {
+			} catch (NullPointerException e) {}
-			}
 
 		} catch (UnauthorizedException e) {
 			// if unauth, requeue message.
@@ -55,10 +76,11 @@ public class Stop extends Thread {
 	@Override
 	public void run() {
 		try {
-			for (;;) {
+			for (;;)
 				displayInfos(indent);
-			}
 		} catch (InterruptedException | ExitException e) {
+			if (e.getClass() != ExitException.class)
+				Logger.getInstance().print(id, e.toString());
 		}
 	}
 
@@ -74,10 +96,10 @@ public class Stop extends Thread {
 	}
 
 	// return all passenger that stops at a stop in the list
-	public ArrayList<Passenger> getPassengerByDest(Trip t, int indexStart) {
+	public ArrayList<Passenger> getPassengerByDest(Line l, int indexStart) {
 		ArrayList<Passenger> res = new ArrayList<Passenger>();
 		// for all given stop
-		for (Stop s : t.getStops(indexStart)) {
+		for (Stop s : l.getStops(indexStart)) {
 			// for all passenger at this stop
 			for (Passenger p : passengers) {
 				// if they stop at this stop, add to res
@@ -124,11 +146,13 @@ public class Stop extends Thread {
 		printDetails(0);
 	}
 
-	public synchronized void removePassenger(Passenger p) {
+	public void removePassenger(Passenger p) throws IOException {
-		if(passengers.remove(p))
+		if(passengers.remove(p)) {
 			synchronized (p) {
 				p.notify();
 			}
+		}
+		sendCurrentCapacity();
 	}
 
 	public void setIndent(int indent) {
@@ -142,4 +166,8 @@ public class Stop extends Thread {
 	public void setThreadPool(ExecutorService threads) {
 		this.threads = threads;
 	}
+
+	public void setSocketPort(int port) {
+		socketPort = port;
+	}
 }