Integrated MQTT clients

api/src/main/java/be/naaturel/boardmateapi/services/MqttService.java

@@ -0,0 +1,60 @@
+package be.naaturel.boardmateapi.services;
+
+import be.naaturel.boardmateapi.common.exceptions.ServiceException;
+import be.naaturel.boardmateapi.common.helpers.Logger;
+import org.eclipse.paho.client.mqttv3.*;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.stereotype.Service;
+
+@Service
+public class MqttService {
+
+    private final MqttClient publisher;
+    private final MqttClient subscriber;
+
+    public MqttService(
+            @Qualifier("mqttPublisher") MqttClient publisher,
+            @Qualifier("mqttSubscriber") MqttClient subscriber
+            ) {
+        this.publisher = publisher;
+        this.subscriber = subscriber;
+    }
+
+    public void publish(String topic, String payload) throws ServiceException {
+        try {
+            MqttMessage message = new MqttMessage(payload.getBytes());
+            message.setQos(1);
+            if(!publisher.isConnected()){
+                publisher.connect();
+            }
+            publisher.publish(topic, message);
+            Logger.displayInfo("Published message: " + payload);
+        } catch (MqttException e) {
+            throw new ServiceException("Unable to publish message", e);
+        } finally {
+            try{
+                if (publisher.isConnected()) publisher.disconnect();
+            } catch (MqttException e){
+                Logger.displayError("Failed to disconnect MQTT client: " + e.getMessage());
+            }
+        }
+    }
+
+    public void subscribe(String topic) throws ServiceException {
+        try {
+            MqttConnectOptions options = new MqttConnectOptions();
+            options.setAutomaticReconnect(true);
+            options.setCleanSession(true);
+
+            if(!subscriber.isConnected()){
+                subscriber.connect(options);
+            }
+            subscriber.subscribe(topic, 1);
+            Logger.displayInfo("Subscribed to topic: " + topic);
+
+        } catch (MqttException e) {
+            throw new ServiceException("Unable to subscribe", e);
+        }
+    }
+
+}