MqttLogger.java

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package net.acesinc.data.json.generator.log;

import java.util.Map;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
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;

/**
 * Created by ygalblum on 11/24/16.
 */
public class MqttLogger implements EventLogger {
    private static final Logger log = LogManager.getLogger(MqttLogger.class);
    
    /* Constants fpr Properties names */
    private static final String PRODUCER_TYPE_NAME = "mqtt";
    private static final String BROKER_SERVER_PROP_NAME = "broker.server";
    private static final String BROKER_PORT_PROP_NAME = "broker.port";
    private static final String TOPIC_PROP_NAME = "topic";
    private static final String CLIENT_ID_PROP_NAME = "clientId";
    private static final String QOS_PROP_NAME = "qos";
    private static final String USERNAME_PROP_NAME = "username";
    private static final String PASSWORD_PROP_NAME = "password";

    /* Constants for default values */
    private static final String DEFAULT_CLIENT_ID     = "JsonGenerator";
    private static final int DEFAULT_QOS = 2;
    
    /* Instance properties */
    private final MqttClient mqttClient;
    private final String topic;
    private final int qos;
    
    public MqttLogger(Map<String, Object> props) throws MqttException {
        String brokerHost = (String) props.get(BROKER_SERVER_PROP_NAME);
        Integer brokerPort = (Integer) props.get(BROKER_PORT_PROP_NAME);
        String brokerAddress = brokerHost + ":" + brokerPort.toString();
        
        String clientId = (String) props.get(CLIENT_ID_PROP_NAME);
        String username = (String)props.get(USERNAME_PROP_NAME);
        String password = (String)props.get(PASSWORD_PROP_NAME);

        topic = (String) props.get(TOPIC_PROP_NAME);
        Integer _qos = (Integer) props.get(QOS_PROP_NAME);
        qos = null == _qos ? DEFAULT_QOS : _qos;
        
        mqttClient = new MqttClient(brokerAddress,
                null == clientId ? DEFAULT_CLIENT_ID : clientId);
        MqttConnectOptions connOpts = new MqttConnectOptions();
        connOpts.setCleanSession(true);
        if (null != username) {
            connOpts.setUserName(username);
            if (null != password) {
                connOpts.setPassword(password.toCharArray());
            }
        }

        log.debug("Connecting to broker: "+brokerAddress);
        mqttClient.connect(connOpts);
        log.debug("Connected");
    }

    @Override
    public void logEvent(String event, Map<String, Object> producerConfig) {
        String _topic = null;
        Integer _qos = null;
        Object value = producerConfig.get(PRODUCER_TYPE_NAME);
        if (null != value && Map.class.isAssignableFrom(value.getClass())) {
            Map<String, Object> config = (Map<String, Object>) value;
            _topic = (String) config.get(TOPIC_PROP_NAME);
            _qos = (Integer) config.get(QOS_PROP_NAME);
        }
        logEvent(event, null == _topic ? topic : _topic, null == _qos ? qos : _qos);
    }
    
    /**
     *
     * @param event the value of event
     * @param qos the value of qos
     * @param topic the value of topic
     */
    private void logEvent(String event, String topic, int qos) {
        MqttMessage message = new MqttMessage(event.getBytes());
        message.setQos(qos);
        try {
            mqttClient.publish(topic, message);
            log.debug("Message published");
        } catch (MqttException ex) {
            log.error("Failed to publish message", ex);
        }
    }

    @Override
    public void shutdown() {
        if (null != mqttClient) {
            try {
                mqttClient.disconnect();
                System.out.println("Disconnected");
            } catch (MqttException ex) {
                log.error("Error in disconnect", ex);
            }
        }
    }
}