Bug 153993 [Viewers] Common Baseclass for Tree/TableEditorImpl
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TableTreeViewer.java
return getTableTree().getTable().getColumnCount();
        }
        Item[] getSelection() {
            return getTableTree().getSelection();
        }
        void setEditor(Control w, Item item, int columnNumber) {
            tableTreeEditor.setEditor(w, (TableTreeItem) item, columnNumber);
        }
        void setSelection(StructuredSelection selection, boolean b) {
            TableTreeViewer.this.setSelection(selection, b);
        }
        void showSelection() {
            getTableTree().showSelection();
        }
        void setLayoutData(CellEditor.LayoutData layoutData) {
            tableTreeEditor.horizontalAlignment = layoutData.horizontalAlignment;
            tableTreeEditor.grabHorizontal = layoutData.grabHorizontal;
            tableTreeEditor.minimumWidth = layoutData.minimumWidth;
        }
        void handleDoubleClickEvent() {
            Viewer viewer = getViewer();
            fireDoubleClick(new DoubleClickEvent(viewer, viewer.getSelection()));
            fireOpen(new OpenEvent(viewer, viewer.getSelection()));
        }
    }
    /**
     * Creates a table tree viewer on the given table tree control.
     * The viewer has no input, no content provider, a default label provider, 
     * no sorter, and no filters.