Bug 315281 update copyrights for 3.6
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/viewers/ViewersObservables.java
}
	/**
	 * Returns an observable set that tracks the checked elements of the given
	 * viewer. Assumes that the viewer implements {@link ICheckable}.
	 * 
	 * @param viewer
	 *            {@link CheckboxTableViewer} containing the checked elements to
	 *            track.
	 * @param elementType
	 *            element type of the returned set
	 * @return an observable set that tracks the checked elements of the given
	 *         viewer.
	 * @since 1.2
	 */
	public static IViewerObservableSet observeCheckedElements(
			CheckboxTableViewer viewer, Object elementType) {
		checkNull(viewer);
		return ViewerProperties.checkedElements(elementType).observe(viewer);
	}
	/**
	 * Returns an observable set that tracks the checked elements of the given
	 * viewer. Assumes that the viewer implements {@link ICheckable}.
	 * 
	 * @param viewer
	 *            {@link CheckboxTreeViewer} containing the checked elements to
	 *            track.
	 * @param elementType
	 *            element type of the returned set
	 * @return an observable set that tracks the checked elements of the given
	 *         viewer.