Bug 82240 [Viewers] Need a content provider for tables that gets elements lazily
Currently all of our viewers assume that all of the elements are avialble. In the case of a virtual table we also want to be able to load elements as they become visible rather than all at once (common issue for databases). Here are some of the issues 1) Need to setItemCount on the table from the content provider 2) Need a getElements(start,finish) method on the content provider 3) Need to decide how to handle staleness. If there are a million items and the viewer just sits there scrolled to the bottom that is a million TableItems and a million Objects represented. How do we manage memory for this?
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
*/
	public void refresh(boolean updateLabels) {
		refresh(getRoot(), updateLabels);
	}
	/**
	 * Refreshes this viewer starting with the given element.
	 * <p>
	 * Unlike the <code>update</code> methods, this handles structural changes
	 * to the given element (e.g. addition or removal of children). If only the
	 * given element needs updating, it is more efficient to use the
	 * <code>update</code> methods.
	 * </p>
	 * 
	 * @param element
	 *            the element
	 */
	public void refresh(final Object element) {
		preservingSelection(new Runnable() {
			public void run() {
				internalRefresh(element);
			}
		});
	}
	/**
	 * Refreshes this viewer starting with the given element. Labels are updated
	 * as described in <code>refresh(boolean updateLabels)</code>.
	 * <p>
	 * Unlike the <code>update</code> methods, this handles structural changes
	 * to the given element (e.g. addition or removal of children). If only the
	 * given element needs updating, it is more efficient to use the