/**
 * <p style="text-indent: 2em;">
 * An interface of <code>component</code> classes requiring the user's focus. For example, the [[ContextMenu]] which that it requires the user to focus on itself
 * all the time it is being displayed. Once the user click on anywhere else outside its area (losing its focus), the [[ContextMenu]] will be disappeared. For this
 * kind of requirement, the [[ContextMenu]] must implement this interface and register itself as a <code>focusing component</code> to [[NeedFocusService]] (via
 * [[NeedFocusService.setFocusingComponent]] method). Then, [[NeedFocusService]] will automatically call [[onFocus]] callback method on the <code>focusing
 * component</code>. Once the component loses its focus, [[NeedFocusService]] will automatically call [[onLostFocus]] callback method.
 * </p>
 *
 * @author shiorin, tee4cute
 * @see [[NeedFocusService]]
 */
export interface INeedFocus {
    /**
     * <p style="text-indent: 1em;">
     * A callback method automatically called by [[NeedFocusService]] when <code>this</code> component loses its focus.
     * </p>
     *
     * @param event The source UI <code>event</code> causing <code>this</code> component to lose its focus.
     */
    onLostFocus(event: any): void;
    /**
     * <p style="text-indent: 1em;">
     * A callback method automatically called by [[NeedFocusService]] when <code>this</code> component gains the focus.
     * </p>
     *
     * @param event The source UI <code>event</code> causing <code>this</code> component to gain the focus.
     */
    onFocus(event: any): void;
}