IoT MQTT Übung Beispiel-Lösung Farbkreis

hue.java

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

public class Main {
    private static MqttClient client;
    private static int interval = 5;
    private static String topic  = "GGBB";

    private static void connect(String broker, String myId, MemoryPersistence persistence) throws MqttException {
        client = new MqttClient(broker, myId, persistence);
        MqttConnectOptions connOpts = new MqttConnectOptions();
        connOpts.setCleanSession(true);

        System.out.print("- Connecting to broker ");
        client.connect(connOpts);
        System.out.println(" [Ok]");
    }

    private static void hue() throws MqttException {
        System.out.println("- Start hue…");

        for(int i = 1; i <= 10; i += 1) {
            System.out.println("   - Round " + i);

            set("red", 100);
            set("blue", 0);

            for(int d = 0; d <= 100; d += interval) {
                set("green", d);
                sleep();
            }
            for(int d = 100; d >= 0; d -= interval) {
                set("red", d);
                sleep();
            }
            for(int d = 0; d <= 100; d += interval) {
                set("blue", d);
                sleep();
            }
            for(int d = 100; d >= 0; d -= interval) {
                set("green", d);
                sleep();
            }
            for(int d = 0; d <= 100; d += interval) {
                set("red", d);
                sleep();
            }
            for(int d = 100; d >= 0; d -= interval) {
                set("blue", d);
                sleep();
            }
        }
    }

    private static void set(String color, int value) throws MqttException {
        String content = color + ":" + value;

        MqttMessage message = new MqttMessage(content.getBytes());
        message.setQos(0);

        client.publish(topic, message);
    }

    private static void sleep() {
        try {
            Thread.sleep(50);
        }
        catch(InterruptedException e) {
            // ignore it for now :P
        }
    }

    public static void main(String[] args) {
        String broker = "tcp://iot.sebbo.net:1883";
        String myId   = "sebastian.pekarek";
        MemoryPersistence persistence = new MemoryPersistence();

        try {
            connect(broker, myId, persistence);
            hue();

            set("red", 0);
            set("green", 0);
            set("blue", 0);
            client.disconnect();

            System.out.println("- Done 🙌");
            System.exit(0);
        }
        catch(MqttException e) {
            System.out.println("## Ups, there was an MQTT error:");
            System.out.println("Reason: " + e.getReasonCode());
            System.out.println("Message: " + e.getMessage());
            System.out.println("Localized Message: " + e.getLocalizedMessage());
            System.out.println("Cause: " + e.getCause());
            System.out.println("Excpetion: " + e);
            e.printStackTrace();
        }
    }
}