MqttHandler.jadd

import java.io.IOException;
import java.util.ArrayList;
import java.util.concurrent.TimeUnit;

aspect MqttHandler {
public class MqttServerHandler {
  private final java.util.Map<String, MqttHandler> handlers = new java.util.HashMap<>();
  private final java.util.Map<ConnectToken, Object> tokensForRemoval = new java.util.HashMap<>();
  private long time;
  private java.util.concurrent.TimeUnit unit;
  private String name;

  public MqttServerHandler() {
    this("RagConnect");
  }

  public MqttServerHandler(String name) {
    this.name = name;
    setupWaitUntilReady(1, TimeUnit.SECONDS);
  }

  public void setupWaitUntilReady(long time, java.util.concurrent.TimeUnit unit) {
    this.time = time;
    this.unit = unit;
  }

  public MqttHandler resolveHandler(java.net.URI uri) throws IOException {
    MqttHandler handler = handlers.get(uri.getHost());
    if (handler == null) {
      // first connect to that server
      handler = new MqttHandler();
      if (uri.getPort() == -1) {
        handler.setHost(uri.getHost());
      } else {
        handler.setHost(uri.getHost(), uri.getPort());
      }
      handlers.put(uri.getHost(), handler);
    }
    handler.waitUntilReady(this.time, this.unit);
    return handler;
  }

  public ConnectToken newConnection(java.net.URI uri, java.util.function.Consumer<byte[]> callback) throws IOException {
    ConnectToken connectToken = new ConnectToken(uri);
    resolveHandler(uri).newConnection(extractTopic(uri), callback);
    tokensForRemoval.put(connectToken, callback);
    return connectToken;
  }

  public boolean disconnect(ConnectToken connectToken) throws IOException {
    MqttHandler handler = resolveHandler(connectToken.uri);
    return handler != null ? handler.disconnect(extractTopic(connectToken.uri), tokensForRemoval.get(connectToken)) : false;
  }

  public void publish(java.net.URI uri, byte[] bytes) throws IOException {
    resolveHandler(uri).publish(extractTopic(uri), bytes);
  }

  public void publish(java.net.URI uri, byte[] bytes, boolean retain) throws IOException {
    resolveHandler(uri).publish(extractTopic(uri), bytes, retain);
  }

  public void publish(java.net.URI uri, byte[] bytes,
                      org.fusesource.mqtt.client.QoS qos, boolean retain) throws IOException {
    resolveHandler(uri).publish(extractTopic(uri), bytes, qos, retain);
  }

  public static String extractTopic(java.net.URI uri) {
    String path = uri.getPath();
    if (path.charAt(0) == '/') {
      path = path.substring(1);
    }
    return path;
  }

  public void close() {
    for (MqttHandler handler : handlers.values()) {
      handler.close();
    }
  }

}
/**
 * Helper class to receive updates via MQTT and use callbacks to handle those messages.
 *
 * @author rschoene - Initial contribution
 */
public class MqttHandler {
  private static final int DEFAULT_PORT = 1883;

  private final org.apache.logging.log4j.Logger logger;
  private final String name;

  /** The host running the MQTT broker. */
  private java.net.URI host;
  /** The connection to the MQTT broker. */
  private org.fusesource.mqtt.client.CallbackConnection connection;
  /** Whether we are connected yet */
  private final java.util.concurrent.CountDownLatch readyLatch;
  private boolean sendWelcomeMessage = true;
  private org.fusesource.mqtt.client.QoS qos;
  /** Dispatch knowledge */
  private final java.util.Map<String, java.util.List<java.util.function.Consumer<byte[]>>> callbacks;

  public MqttHandler() {
    this("RagConnect");
  }

  public MqttHandler(String name) {
    this.name = java.util.Objects.requireNonNull(name, "Name must be set");
    this.logger = org.apache.logging.log4j.LogManager.getLogger(MqttHandler.class);
    this.callbacks = new java.util.HashMap<>();
    this.readyLatch = new java.util.concurrent.CountDownLatch(1);
    this.qos = org.fusesource.mqtt.client.QoS.AT_LEAST_ONCE;
  }

  public MqttHandler dontSendWelcomeMessage() {
    this.sendWelcomeMessage = false;
    return this;
  }

  /**
   * Sets the host (with default port) to receive messages from, and connects to it.
   * @throws IOException if could not connect, or could not subscribe to a topic
   * @return self
   */
  public MqttHandler setHost(String host) throws java.io.IOException {
    return setHost(host, DEFAULT_PORT);
  }

  /**
   * Sets the host to receive messages from, and connects to it.
   * @throws IOException if could not connect, or could not subscribe to a topic
   * @return self
   */
  public MqttHandler setHost(String host, int port) throws java.io.IOException {
    java.util.Objects.requireNonNull(host, "Host need to be set!");

    this.host = java.net.URI.create("tcp://" + host + ":" + port);
    logger.debug("Host for {} is {}", this.name, this.host);

    org.fusesource.mqtt.client.MQTT mqtt = new org.fusesource.mqtt.client.MQTT();
    mqtt.setHost(this.host);
    connection = mqtt.callbackConnection();
    java.util.concurrent.atomic.AtomicReference<Throwable> error = new java.util.concurrent.atomic.AtomicReference<>();

    // add the listener to dispatch messages later
    connection.listener(new org.fusesource.mqtt.client.ExtendedListener() {
      public void onConnected() {
        logger.debug("Connected");
      }

      @Override
      public void onDisconnected() {
        logger.debug("Disconnected");
      }

      @Override
      public void onPublish(org.fusesource.hawtbuf.UTF8Buffer topic,
                            org.fusesource.hawtbuf.Buffer body,
                            org.fusesource.mqtt.client.Callback<org.fusesource.mqtt.client.Callback<Void>> ack) {
        // this method is called, whenever a MQTT message is received
        String topicString = topic.toString();
        // TODO: maybe copy list here to avoid concurrent modification. or use a concurrent list.
        java.util.List<java.util.function.Consumer<byte[]>> callbackList = new java.util.ArrayList<>(callbacks.get(topicString));
        if (callbackList == null || callbackList.isEmpty()) {
          logger.debug("Got a message at {}, but no callback to call. Forgot to subscribe?", topic);
        } else {
          byte[] message = body.toByteArray();
          logger.debug("initial: {}", callbackList);
          for (java.util.function.Consumer<byte[]> callback : callbackList) {
            logger.debug("before: {}", callbackList);
            callback.accept(message);
            logger.debug("after: {}", callbackList);
          }
        }
        ack.onSuccess(null);  // always acknowledge message
      }

      @Override
      public void onPublish(org.fusesource.hawtbuf.UTF8Buffer topicBuffer,
                            org.fusesource.hawtbuf.Buffer body,
                            Runnable ack) {
        // not used by this type of connection
        logger.warn("onPublish should not be called");
      }

      @Override
      public void onFailure(Throwable cause) {
        error.set(cause);
      }
    });
    throwIf(error);

    // actually establish the connection
    connection.connect(new org.fusesource.mqtt.client.Callback<Void>() {
      @Override
      public void onSuccess(Void value) {
        if (MqttHandler.this.sendWelcomeMessage) {
          connection.publish("components",
                             (name + " is connected").getBytes(),
                             org.fusesource.mqtt.client.QoS.AT_LEAST_ONCE,
                             false,
                             new org.fusesource.mqtt.client.Callback<Void>() {
            @Override
            public void onSuccess(Void value) {
              logger.debug("success sending welcome message");
              setReady();
            }

            @Override
            public void onFailure(Throwable value) {
              logger.debug("failure sending welcome message", value);
            }
          });
        } else {
          setReady();
        }
      }

      @Override
      public void onFailure(Throwable cause) {
        error.set(cause);
      }
    });
    throwIf(error);
    return this;
  }

  public java.net.URI getHost() {
    return host;
  }

  private void setReady() {
    readyLatch.countDown();
  }

  private void throwIf(java.util.concurrent.atomic.AtomicReference<Throwable> error) throws java.io.IOException {
    if (error.get() != null) {
      throw new java.io.IOException(error.get());
    }
  }

  public void setQoSForSubscription(org.fusesource.mqtt.client.QoS qos) {
    this.qos = qos;
  }

  public boolean newConnection(String topic, java.util.function.Consumer<byte[]> callback) {
    if (readyLatch.getCount() > 0) {
      System.err.println("Handler not ready");
      return false;
    }
    // register callback
    logger.debug("new connection for {}", topic);
    if (callbacks.get(topic) == null || callbacks.get(topic).isEmpty()) {
      callbacks.put(topic, new java.util.ArrayList<>());

      // subscribe at broker
      org.fusesource.mqtt.client.Topic[] topicArray = { new org.fusesource.mqtt.client.Topic(topic, this.qos) };
      connection.getDispatchQueue().execute(() -> {
        connection.subscribe(topicArray, new org.fusesource.mqtt.client.Callback<byte[]>() {
          @Override
          public void onSuccess(byte[] qoses) {
            logger.debug("Subscribed to {}, qoses: {}", topic, qoses);
          }

          @Override
          public void onFailure(Throwable cause) {
            logger.error("Could not subscribe to {}", topic, cause);
          }
        });
      });
    }
    callbacks.get(topic).add(callback);
    return true;
  }

  public boolean disconnect(String topic, Object callback) {
    java.util.List<java.util.function.Consumer<byte[]>> callbackList = callbacks.get(topic);
    if (callbackList == null) {
      logger.warn("Disconnect for not connected topic '{}'", topic);
      return false;
    }
    java.util.concurrent.atomic.AtomicReference<Boolean> success = new java.util.concurrent.atomic.AtomicReference<>();
    success.set(callbackList.remove(callback));
    if (callbackList.isEmpty()) {
      // no callbacks anymore for this topic, unsubscribe from mqtt
      connection.getDispatchQueue().execute(() -> {
        org.fusesource.hawtbuf.UTF8Buffer topicBuffer = org.fusesource.hawtbuf.Buffer.utf8(topic);
        org.fusesource.hawtbuf.UTF8Buffer[] topicArray = new org.fusesource.hawtbuf.UTF8Buffer[]{topicBuffer};
        connection.unsubscribe(topicArray, new org.fusesource.mqtt.client.Callback<Void>() {
          @Override
          public void onSuccess(Void value) {
            // empty, all good
          }

          @Override
          public void onFailure(Throwable cause) {
            success.set(false);
          }
        });
      });
    }
    return success.get();
  }

  /**
   * Waits until this updater is ready to receive MQTT messages.
   * If it already is ready, return immediately with the value <code>true</code>.
   * Otherwise waits for the given amount of time, and either return <code>true</code> within the timespan,
   * if it got ready, or <code>false</code> upon a timeout.
   * @param time the maximum time to wait
   * @param unit the time unit of the time argument
   * @return whether this updater is ready
   */
  public boolean waitUntilReady(long time, java.util.concurrent.TimeUnit unit) {
    try {
      return readyLatch.await(time, unit);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    return false;
  }

  public void close() {
    if (connection == null) {
      logger.warn("Stopping without connection. Was setHost() called?");
      return;
    }
    connection.getDispatchQueue().execute(() -> {
      connection.disconnect(new org.fusesource.mqtt.client.Callback<Void>() {
        @Override
        public void onSuccess(Void value) {
          logger.info("Disconnected {} from {}", name, host);
        }

        @Override
        public void onFailure(Throwable ignored) {
          // Disconnects never fail. And we do not care either.
        }
      });
    });
  }

  public void publish(String topic, byte[] bytes) {
    publish(topic, bytes, false);
  }

  public void publish(String topic, byte[] bytes, boolean retain) {
    publish(topic, bytes, this.qos, retain);
  }

  public void publish(String topic, byte[] bytes, org.fusesource.mqtt.client.QoS qos, boolean retain) {
    connection.getDispatchQueue().execute(() -> {
      connection.publish(topic, bytes, qos, retain, new org.fusesource.mqtt.client.Callback<Void>() {
        @Override
        public void onSuccess(Void value) {
          logger.debug("Published some bytes to {}", topic);
        }

        @Override
        public void onFailure(Throwable value) {
          logger.warn("Could not publish on topic '{}'", topic, value);
        }
      });
    });
  }
}
}