/**
  * Initialize the plugin by setting localization and loading public scripts
  * and styles.
  *
  * @since     1.0.0
  */
 private function __construct()
 {
     // Load plugin text domain
     add_action('init', array($this, 'load_plugin_textdomain'));
     // Activate plugin when new blog is added
     add_action('wpmu_new_blog', array($this, 'activate_new_site'));
     // Load public-facing style sheet and JavaScript.
     add_action('wp_enqueue_scripts', array($this, 'enqueue_styles'));
     self::$default_options = array('sa_source_posttypes' => array('post' => 1), 'sa_source_title' => 'Source :', 'sa_source_style' => 'COMMA', 'sa_source_open_style' => 'BLANK', 'sa_source_position' => 'APPEND');
     $this->_setDefaultOptions();
     //get current options
     $this->_getCurrentOptions();
     /**
      * Define custom functionality.
      */
     add_filter('the_content', array($this, 'source_affix_affix_sa_source'));
 }