private function hook_plugin_action_links() {
            $this->_logger->entrance();

            $this->_action_links_hooked = true;

            $this->_logger->log( 'Adding action links hooks.' );

            // Add action link to settings page.
            add_filter( 'plugin_action_links_' . $this->_plugin_basename, array(
                &$this,
                '_modify_plugin_action_links_hook'
            ), WP_FS__DEFAULT_PRIORITY, 2 );
            add_filter( 'network_admin_plugin_action_links_' . $this->_plugin_basename, array(
                &$this,
                '_modify_plugin_action_links_hook'
            ), WP_FS__DEFAULT_PRIORITY, 2 );
        }