A widget that implements this interface has the ability to override the document directionality for its root element.

Widgets that implement this interface should be leaf widgets. More specifically, they should not implement the {@link com.google.gwt.user.client.ui.HasWidgets} interface.

abstract class HasDirection {

 /**
  * Sets the directionality for a widget.
  *
  * @param value <code>RTL</code> if the directionality should be set to right-to-left,
  *                  <code>LTR</code> if the directionality should be set to left-to-right
  *                  <code>DEFAULT</code> if the directionality should not be explicitly set
  */
 void set direction(Direction value);

 /**
  * Gets the directionality of the widget.
  *
  * @return <code>RTL</code> if the directionality is right-to-left,
  *         <code>LTR</code> if the directionality is left-to-right, or
  *         <code>DEFAULT</code> if the directionality is not explicitly specified
  */
 Direction get direction;
}