public function set_url() {

		$plugins_url = plugins_url();
		$this_url    = trim( substr( trailingslashit( plugin_dir_url( __FILE__ ) ), strlen( $plugins_url ) ), '/' );

		if ( false !== strpos( $this_url, '/' ) ) {
			$url_path = explode( '/', $this_url );
			// generic 3 path depth: classes/namespace/ui|data.
			array_splice( $url_path, count( $url_path ) - 3 );
			$this_url = implode( '/', $url_path );
		}
		// setup the base URL.
		$this->url = trailingslashit( $plugins_url . '/' . $this_url );
	}