Bug 151205 [Viewers] Add setFilters() to change multiple filters at once efficiently
When one needs to add more than one filter after every request a refresh command is issued which is not desired an API-Function where the user could control whether the refresh is called or not would be a great performance improvement.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
* 				not an instance of ViewerSorter
	 */
	public ViewerSorter getSorter() {
		if (sorter instanceof ViewerSorter)
			return (ViewerSorter)sorter;
		return null;
	}
	/**
	 * Return this viewer's comparator used to sort elements.
	 * This method should be used instead of <code>getSorter()</code>.
	 * 
	 * @return a viewer comparator, or <code>null</code> if none
     *
	 * @since 3.2
	 */
	public ViewerComparator getComparator(){
		return sorter;
	}
	
	/**
	 * Handles a double-click select event from the widget.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.
	 * </p>
	 * 
	 * @param event
	 *            the SWT selection event
	 */
	protected void handleDoubleSelect(SelectionEvent event) {