function Client(brokerUrl, clientId) {
  var Callback = org.walterhiggins.scriptcraft.ScriptCraftMqttCallback;
  var MqttClient = org.eclipse.paho.client.mqttv3.MqttClient;

  var callback = new Callback(
    function(err) {
      console.log('connectionLost: ' + err);
    },
    function(topic, message) {
      console.log('messageArrived ' + topic + '> ' + message);
    },
    function(token) {
      console.log('deliveryComplete:' + token);
    }
  );

  if (!brokerUrl) {
    brokerUrl = 'tcp://localhost:1883';
  }
  if (!clientId) {
    clientId = 'scriptcraft' + new Date().getTime();
  }
  var client = new MqttClient(brokerUrl, clientId, null);
  client.setCallback(callback);
  return {
    connect: function(options) {
      if (typeof options === 'undefined') {
        client.connect();
      } else {
        client.connect(options);
      }
      return client;
    },

    disconnect: function(quiesceTimeout) {
      if (typeof quiesceTimeout == 'undefined') {
        client.disconnect();
      } else {
        client.disconnect(quiesceTimeout);
      }
      return client;
    },

    publish: function(topic, message, qos, retained) {
      if (typeof message == 'string') {
        message = new java.lang.String(message).bytes;
      }
      if (typeof qos == 'undefined') {
        qos = 1;
      }
      if (typeof retained == 'undefined') {
        retained = false;
      }
      client.publish(topic, message, qos, retained);
      return client;
    },

    subscribe: function(topic) {
      client.subscribe(topic);
      return client;
    },

    unsubscribe: function(topic) {
      client.unsubscribe(topic);
      return client;
    },

    onMessageArrived: function(fn) {
      callback.setMesgArrived(fn);
      return client;
    },

    onDeliveryComplete: function(fn) {
      callback.setDeliveryComplete(fn);
      return client;
    },

    onConnectionLost: function(fn) {
      callback.setConnLost(fn);
      return client;
    }
  };
}
**********************************************************************
## sc-mqtt module

This module provides a simple way to communicate with devices (such as Arduino)
using the popular lightweight [MQTT protocol][mqtt].

### Usage

This module can only be used if the separate `sc-mqtt.jar` file is
present in the CraftBukkit classpath. To use this module, you should
...

 1. Download sc-mqtt.jar from <https://scriptcraftjs.org/download/extras/>
 2. Save the file to the same directory where craftbukkit.jar resides.
 3. Create a new batch file (windows-only) called
    craftbukkit-sc-mqtt.bat and edit it to include the following
    command...

    ```sh
    java -classpath sc-mqtt.jar;craftbukkit.jar org.bukkit.craftbukkit.Main
    ```

    If you're using Mac OS, create a new craftbukkit-sc-mqtt.command
    file and edit it (using TextWrangler or another text editor) ...

    ```sh
    java -classpath sc-mqtt.jar:craftbukkit.jar org.bukkit.craftbukkit.Main
    ```

 4. Execute the craftbukkit-sc-mqtt batch file / command file to start
    Craftbukkit. You can now begin using this module to send and receive
    messages to/from a Net-enabled Arduino or any other device which uses
    the [MQTT protocol][mqtt]
  
    ```javascript
    var mqtt = require('sc-mqtt');
    // create a new client
    var client = mqtt.client( 'tcp://localhost:1883', 'uniqueClientId' );
    // connect to the broker 
    client.connect( { keepAliveInterval: 15 } );
    //  publish a message to the broker
    client.publish( 'minecraft', 'loaded' );
    // subscribe to messages on 'arduino' topic 
    client.subscribe( 'arduino' );
    //  do something when an incoming message arrives...
    client.onMessageArrived( function( topic, message ) {
        console.log( 'Message arrived: topic=' + topic + ', message=' + message );
    });

    ```

The `sc-mqtt` module provides a very simple minimal wrapper around the
[Eclipse Paho MQTT Version 3 Client][pahodocs] java-based MQTT
library.

[pahodocs]: http://pic.dhe.ibm.com/infocenter/wmqv7/v7r5/index.jsp?topic=/com.ibm.mq.javadoc.doc/WMQMQxrClasses/org/eclipse/paho/client/mqttv3/package-summary.html
[mqtt]: http://mqtt.org/
*