Jimbo.Cheerlights.MQTTListener.java Source code

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Here is the source code for Jimbo.Cheerlights.MQTTListener.java

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/*
 * Copyright (C) 2017 Jim Darby.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see
 * <http://www.gnu.org/licenses/>.
 */

package Jimbo.Cheerlights;

import Jimbo.MQTT.MQTTClient;
import Jimbo.MQTT.MQTTMessageRecipient;

import java.io.IOException;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;

import java.util.logging.Level;
import java.util.logging.Logger;

import org.apache.commons.cli.ParseException;

import org.eclipse.paho.client.mqttv3.MqttException;

import org.json.JSONObject;
import org.json.JSONException;

/**
 * Class to listen to MQTT CheerLights tweets and process them. In
 * other words it's an adaptor that turns a MQTTMessageRecipient into a
 * CheerListener.
 * 
 * @author Jim Darby
 */
public class MQTTListener implements MQTTMessageRecipient {
    private static final Logger LOG = Logger.getLogger("MQTTListener");

    /**
     * Create a MQTTListener, listen, parse and then feed the results
     * (if correct) into the target.
     * 
     * @param broker The URI of the MQTT broker
     * @param client Our client name for the broker
     * @param topic The topic name to listen to
     * @param target The CheerListener to feed to results to
     * 
     * @throws ParseException In case of error
     * @throws MqttException In case of error
     */
    public MQTTListener(String broker, String client, String topic, CheerListener target)
            throws ParseException, MqttException {
        MQTTClient listener = new MQTTClient(broker, client, topic, this);

        this.target = target;

        listener.run();
    }

    /**
     * Receive an MQTT message.
     * 
     * @param topic The topic it's on
     * @param message The message itself
     */
    @Override
    public void receive(String topic, String message) {
        try {
            JSONObject j = new JSONObject(message);

            final Instant instant = Instant.ofEpochMilli(j.getLong("sent")).truncatedTo(ChronoUnit.SECONDS);
            final LocalDateTime stamp = LocalDateTime.ofInstant(instant, ZONE);
            final String when = stamp.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);

            LOG.log(Level.INFO, "{0} (@{1}) sent {2}: {3}",
                    new Object[] { j.getString("name"), j.getString("screen"), when, j.getString("text") });
            target.update(j.getInt("colour"));
        }

        catch (JSONException | IOException e) {
            LOG.log(Level.WARNING, "Unable to parse: \"{0}\": {1}",
                    new Object[] { message, e.getLocalizedMessage() });
        }
    }

    /** The listener we forward the new colour to. */
    private final CheerListener target;
    /** Time time zone we're in. Used to format logging information. */
    private static final ZoneId ZONE = ZoneOffset.systemDefault();
}