Bug 163317 [Viewers] Take over SWT programming pattern to JFace Viewers
To open ColumnViewer for reusablility we should not make it final making the constructor protected forces people to subclass it and not directly creating instances from it.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/TableView.java
int[] columnOrder = tree.getColumnOrder();
		for (int i = 0; i < columnOrder.length; i++) {
			IMemento child = memento.createChild(TAG_COLUMN_ORDER);
			child.putInteger(TAG_COLUMN_ORDER_INDEX, columnOrder[i]);
		}
		
		Scrollable scrollable = (Scrollable) viewer.getControl();
		ScrollBar bar = scrollable.getVerticalBar();
		int position = (bar != null) ? bar.getSelection() : 0;
		memento.putInteger(TAG_VERTICAL_POSITION, position);
		
		bar = scrollable.getHorizontalBar();
		position = (bar != null) ? bar.getSelection() : 0;
		memento.putInteger(TAG_HORIZONTAL_POSITION, position);
	}
	private int[] restoreColumnOrder(IMemento memento) {
		if (memento == null) {
			return null;
		}
		IMemento children[] = memento.getChildren(TAG_COLUMN_ORDER);
		if (children != null) {
			int n = children.length;
			int[] values = new int[n];
			for (int i = 0; i < n; i++) {
				Integer val = children[i].getInteger(TAG_COLUMN_ORDER_INDEX);
				if (val != null) {
					values[i] = val.intValue();
				} else {
					
					return null;