Imported code from secret source for websockets (@tommi27 you don't know anything about it, right?)

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/socket/SensorSocketConfig.java

@@ -0,0 +1,26 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.socket;
+
+import javax.websocket.server.ServerEndpointConfig;
+
+public class SensorSocketConfig extends ServerEndpointConfig.Configurator {
+
+    public static SensorSocketEndpoint getInstance() {
+        return instance;
+    }
+
+    private static SensorSocketEndpoint instance = new SensorSocketEndpoint();
+
+    @Override
+    public <T> T getEndpointInstance(Class<T> endpointClass) throws InstantiationException {
+        try {
+            @SuppressWarnings("unchecked")
+            final T instance = (T) SensorSocketConfig.instance;
+            return instance;
+        } catch (ClassCastException e) {
+            final var e2 =
+                    new InstantiationException("Cannot cast SensorSocketEndpoint to desired type");
+            e2.initCause(e);
+            throw e2;
+        }
+    }
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/socket/SensorSocketDecoder.java

@@ -0,0 +1,32 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.socket;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonSyntaxException;
+import javax.websocket.*;
+
+public class SensorSocketDecoder implements Decoder.Text<JsonObject> {
+    private Gson decoder;
+
+    @Override
+    public void init(EndpointConfig endpointConfig) {
+        decoder = new Gson();
+    }
+
+    @Override
+    public void destroy() {}
+
+    @Override
+    public JsonObject decode(String s) throws DecodeException {
+        try {
+            return decoder.fromJson(s, JsonObject.class);
+        } catch (JsonSyntaxException e) {
+            throw new DecodeException(s, "Cannot decode sensor message", e);
+        }
+    }
+
+    @Override
+    public boolean willDecode(String s) {
+        return true;
+    }
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/socket/SensorSocketEncoder.java

@@ -0,0 +1,24 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.socket;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import javax.websocket.EncodeException;
+import javax.websocket.Encoder;
+import javax.websocket.EndpointConfig;
+
+public class SensorSocketEncoder implements Encoder.Text<JsonObject> {
+    private Gson encoder;
+
+    @Override
+    public String encode(JsonObject object) throws EncodeException {
+        return encoder.toJson(object);
+    }
+
+    @Override
+    public void init(EndpointConfig endpointConfig) {
+        encoder = new Gson();
+    }
+
+    @Override
+    public void destroy() {}
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/socket/SensorSocketEndpoint.java

@@ -0,0 +1,41 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.socket;
+
+import com.google.gson.JsonObject;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import javax.websocket.*;
+import javax.websocket.server.ServerEndpoint;
+
+@ServerEndpoint(
+        value = "/service",
+        configurator = SensorSocketConfig.class,
+        encoders = SensorSocketEncoder.class,
+        decoders = SensorSocketDecoder.class)
+public class SensorSocketEndpoint {
+
+    private Set<Session> clients = Collections.synchronizedSet(new HashSet<>());
+
+    public Set<Session> getClients() {
+        return clients;
+    }
+
+    @OnOpen
+    public void onOpen(Session userSession) {
+        clients.add(userSession);
+    }
+
+    @OnClose
+    public void onClose(Session userSession) {
+        clients.remove(userSession);
+    }
+
+    public int broadcast(JsonObject message) throws IOException, EncodeException {
+        for (Session session : clients) {
+            System.out.println(message);
+            session.getBasicRemote().sendObject(message);
+        }
+        return clients.size();
+    }
+}