protected function configure(array $options)
    {
        $this->options = array_merge(array(
            'server_name'      => null,
            'pid'              => null,
            'ps'               => '/bin/ps',
            'ps_args'          => array('-o', 'pid,state', '-p'),
            'id_format'        => '%s:%d:%s',
            'id_location_preg' => '/^([^:]+?):([0-9]+):/',
            'shuffle_queues'   => true,
            'sort_queues'      => false
        ), $options);

        if (!$this->options['server_name']) {
            $this->options['server_name'] = function_exists('gethostname') ? gethostname() : php_uname('n');
        }

        if (!$this->options['pid']) {
            $this->options['pid'] = getmypid();
        }
    }