Add message parameters to discovery method, and add close method

build.gradle

@@ -17,6 +17,7 @@ javafx {
 }
 
 dependencies {
+    implementation 'org.jetbrains:annotations:20.1.0'
     runtimeOnly "org.openjfx:javafx-graphics:$javafx.version:win"
     runtimeOnly "org.openjfx:javafx-graphics:$javafx.version:linux"
     runtimeOnly "org.openjfx:javafx-graphics:$javafx.version:mac"

src/main/java/fr/insa/clavardator/MainApp.java

@@ -1,6 +1,8 @@
 package fr.insa.clavardator;
 
+import fr.insa.clavardator.network.NetDiscoverer;
 import fr.insa.clavardator.ui.MainController;
+import fr.insa.clavardator.util.ErrorHandler;
 import javafx.application.Application;
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Parent;
@@ -32,6 +34,19 @@ public class MainApp extends Application {
 		stage.setMinWidth(800);
 		stage.setMaximized(true);
 		stage.show();
+
+		// Network discovery test
+		ErrorHandler.getInstance().addObserver(evt -> ((Exception)evt.getNewValue()).printStackTrace());
+
+		NetDiscoverer.discoverActiveUsers("Broadcast",
+				(ipAddr, data) -> System.out.println("User detected at address : " + ipAddr.toString())
+		);
+		NetDiscoverer.startDiscoveryListening("Yohan", null);
 	}
 
+	@Override
+	public void stop() throws Exception {
+		NetDiscoverer.stopDiscovery();
+		super.stop();
+	}
 }

src/main/java/fr/insa/clavardator/network/NetDiscoverer.java

@@ -1,6 +1,7 @@
 package fr.insa.clavardator.network;
 
 import fr.insa.clavardator.util.ErrorHandler;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.IOException;
 import java.net.*;
@@ -12,8 +13,12 @@ import java.util.Objects;
 public class NetDiscoverer {
 	private static final short DISCOVERY_PORT = 31593;
 	private static final short RESPONSE_PORT = 31594;
-	public static final int BROADCAST_BUFFER_SIZE = 50;
+	private static final int BROADCAST_BUFFER_SIZE = 50;
-	public static final int RESPONSE_BUFFER_SIZE = 50;
+	private static final int RESPONSE_BUFFER_SIZE = 50;
+
+	private static DatagramSocket broadcastListener;
+	private static DatagramSocket responseListener;
+	private static boolean shouldStop = false;
 
 	private NetDiscoverer() {
 	}
@@ -23,9 +28,9 @@ public class NetDiscoverer {
 	 *
 	 * @param callback function to call when a new user is discovered
 	 */
-	public static void discoverActiveUsers(ResponseReceivedCallback callback) {
+	public static void discoverActiveUsers(String broadcastMessage, ResponseReceivedCallback callback) {
 		ResponseListener receiver = new ResponseListener(callback);
-		BroadcastSender sender = new BroadcastSender("USER_DISCOVERY_BROADCAST");
+		BroadcastSender sender = new BroadcastSender(broadcastMessage);
 		receiver.start();
 		sender.start();
 	}
@@ -33,13 +38,24 @@ public class NetDiscoverer {
 	/**
 	 * Starts to listen for discovery broadcasts and answers them
 	 */
-	public static void startDiscoveryListening() {
+	public static void startDiscoveryListening(String responseMessage, @Nullable BroadcastReceivedCallback onBroadcastReceived) {
-		BroadcastListener listener = new BroadcastListener(
+		BroadcastListener listener = new BroadcastListener((ipAddr, data) -> {
-				(ipAddr, data) -> new ResponseSender(ipAddr, "USER_DISCOVERY_RESPONSE").start()
+			if (onBroadcastReceived != null)
+				onBroadcastReceived.onBroadcastReceived(ipAddr, data);
+			new ResponseSender(ipAddr, responseMessage).start();
+		}
 		);
 		listener.start();
 	}
 
+	public static void stopDiscovery() {
+		shouldStop = true;
+		if (broadcastListener != null)
+			broadcastListener.close();
+		if (responseListener != null)
+			responseListener.close();
+	}
+
 
 	private static class BroadcastSender extends Thread {
 		String broadcastMessage;
@@ -79,22 +95,23 @@ public class NetDiscoverer {
 
 		@Override
 		public void run() {
-			while (true) {      // TODO: add a stop condition
+			while (!shouldStop) {
 				try {
-					DatagramSocket listener = new DatagramSocket(null);
+					broadcastListener = new DatagramSocket(null);
-					listener.setOption(StandardSocketOptions.SO_REUSEPORT, true);
+					broadcastListener.setOption(StandardSocketOptions.SO_REUSEPORT, true);
-					listener.setOption(StandardSocketOptions.SO_REUSEADDR, true);
+					broadcastListener.setOption(StandardSocketOptions.SO_REUSEADDR, true);
-					listener.bind(new InetSocketAddress((InetAddress) null, DISCOVERY_PORT));
+					broadcastListener.bind(new InetSocketAddress((InetAddress) null, DISCOVERY_PORT));
 
 					byte[] buffer = new byte[BROADCAST_BUFFER_SIZE];
 					DatagramPacket receivedPacket = new DatagramPacket(buffer, BROADCAST_BUFFER_SIZE);
 
-					listener.receive(receivedPacket);
+					broadcastListener.receive(receivedPacket);
 //					System.out.println("broadcast received from " + receivedPacket.getAddress().toString());
 					callback.onBroadcastReceived(receivedPacket.getAddress(), new String(receivedPacket.getData()));
 				} catch (IOException e) {
-					e.printStackTrace();
+					if (!shouldStop) {
-					ErrorHandler.getInstance().notifyError(e);
+						ErrorHandler.getInstance().notifyError(e);
+					}
 				}
 			}
 		}
@@ -136,20 +153,22 @@ public class NetDiscoverer {
 
 		@Override
 		public void run() {
-			while (true) {      // TODO: add a stop condition
+			while (!shouldStop) {
 				try {
-					DatagramSocket listener = new DatagramSocket(null);
+					responseListener = new DatagramSocket(null);
-					listener.setOption(StandardSocketOptions.SO_REUSEPORT, true);
+					responseListener.setOption(StandardSocketOptions.SO_REUSEPORT, true);
-					listener.setOption(StandardSocketOptions.SO_REUSEADDR, true);
+					responseListener.setOption(StandardSocketOptions.SO_REUSEADDR, true);
-					listener.bind(new InetSocketAddress((InetAddress) null, RESPONSE_PORT));
+					responseListener.bind(new InetSocketAddress((InetAddress) null, RESPONSE_PORT));
 
 					byte[] buffer = new byte[RESPONSE_BUFFER_SIZE];
 					DatagramPacket receivedPacket = new DatagramPacket(buffer, RESPONSE_BUFFER_SIZE);
-					listener.receive(receivedPacket);
+					responseListener.receive(receivedPacket);
 //					System.out.println("response received from " + receivedPacket.getAddress().toString());
 					callback.onResponseReceived(receivedPacket.getAddress(), new String(receivedPacket.getData()));
 				} catch (IOException e) {
-					ErrorHandler.getInstance().notifyError(e);
+					if (!shouldStop) {
+						ErrorHandler.getInstance().notifyError(e);
+					}
 				}
 			}
 		}

src/main/java/fr/insa/clavardator/users/UserList.java

@@ -48,7 +48,7 @@ public class UserList {
 	 *
 	 */
 	public void discoverActiveUsers() {
-		NetDiscoverer.discoverActiveUsers((ipAddr, data) -> {
+		NetDiscoverer.discoverActiveUsers("CLAVARDATOR_BROADCAST", (ipAddr, data) -> {
 			ActiveUser newUser = new ActiveUser(ipAddr);
 			activeUsers.add(newUser);
 			pcs.firePropertyChange("activeUsers", null, newUser);