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
* model's internal state.
	 * 
	 * @param parent
	 *            the parent element
	 * @return a filtered array of child elements
	 */
	protected Object[] getFilteredChildren(Object parent) {
		Object[] result = getRawChildren(parent);
		if (filters != null) {
			for (Iterator iter = filters.iterator(); iter.hasNext();) {
				ViewerFilter f = (ViewerFilter) iter.next();
				result = f.filter(this, parent, result);
			}
		}
		return result;
	}
	/**
	 * Returns this viewer's filters.
	 * 
	 * @return an array of viewer filters
	 */
	public ViewerFilter[] getFilters() {
		if (filters == null)
			return new ViewerFilter[0];
		ViewerFilter[] result = new ViewerFilter[filters.size()];
		filters.toArray(result);
		return result;
	}
	/**
	 * Returns the item at the given display-relative coordinates, or