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
*/
	protected void mapElement(Object element, Widget item) {
		if (elementMap != null) {
			Object widgetOrWidgets = elementMap.get(element);
			if (widgetOrWidgets == null) {
				elementMap.put(element, item);
			} else if (widgetOrWidgets instanceof Widget) {
				if (widgetOrWidgets != item) {
					elementMap.put(element, new Widget[] {
							(Widget) widgetOrWidgets, item });
				}
			} else {
				Widget[] widgets = (Widget[]) widgetOrWidgets;
				int indexOfItem = Arrays.asList(widgets).indexOf(item);
				if (indexOfItem == -1) {
					int length = widgets.length;
					System.arraycopy(widgets, 0,
							widgets = new Widget[length + 1], 0, length);
					widgets[length] = item;
					elementMap.put(element, widgets);
				}
			}
		}
	}
	/**
	 * Determines whether a change to the given property of the given element
	 * would require refiltering and/or resorting.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.