Postmaster Class for PHP Event Bus Using RabbitMQ

postmaster.php

<?php

class Postmaster {

    private $connection;
    private $channel;

    /**
    * Factory method for creating and instance of Postmaster
    */
    public static function create() {
        return new Postmaster();
    }

    public function __construct() {

        /* get a connection and channel reference */
        $this->connection = new AMQPStreamConnection('127.0.0.1', 5672, 'guest', 'guest');
        $this->channel = $this->connection->channel();

        /*  Make sure the queues we need are set up */
        $this->channel->queue_declare(LETTER_PARCEL_QUEUE_ID,false, false, false , false);
    }

    /**
     * This ensures the channel and connection reference are cleaned up appropriately.
     */
    public function __destruct()
    {
        $this->channel->close();
        $this->connection->close();
    }

    /**
     * This is called by the producers when they want to send a parcel to a Carrier
     */
    public function send(Parcel $parcel) {

        if (null === $parcel) {
            throw new \InvalidArgumentException('You can not provide a null parcel!');
        }

        return $this->pushToQueue($parcel);
    }

    private function pushToQueue(Parcel $parcel) {

        $queueName = null;
        $queueMessage = new AMQPMessage(serialize($parcel));

        /* Only push certain types of parcels to certain queues */
        switch (true) {

            /* Provided cases for matching queueName */
            case $parcel instanceof Letter:
              $queueName = LETTER_PARCEL_QUEUE_ID
        }

        /* Check if the queueName is set - if not - drop on the floor */
        if ($queueName) {
            try {
                $this->channel->basic_publish($queueMessage, '', $queueName);
            } catch (Exception $e) {
                return false;
            }
            return true;
        }

        return false;
    }
}