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.jface/src/org/eclipse/jface/viewers/CellLabelProvider.java
/**
	 * The time in milliseconds until the tool tip is displaued.
	 * 
	 * @param object
	 *            the {@link Object} for which the tool tip is shown
	 * @return int
	 */
	public int getToolTipDisplayDelayTime(Object object) {
		return 0;
	}
	/**
	 * The {@link SWT} style used to create the {@link CLabel} (see there for supported styles). 
	 * By default {@link SWT#SHADOW_NONE} is used.
	 * 
	 * @param object
	 *            the element for which the tool tip is shown
	 * @return int
	 * @see CLabel
	 */
	public int getToolTipStyle(Object object) {
		return SWT.SHADOW_NONE;
	}
	/**
	 * Update the label for cell.
	 * 
	 * @param cell {@link ViewerCell}
	 */
	public abstract void update(ViewerCell cell);
}