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
* <code>null</code> if there is no item at that location.
	 * <p>
	 * The default implementation of this method returns <code>null</code>.
	 * </p>
	 * 
	 * @param x
	 *            horizontal coordinate
	 * @param y
	 *            vertical coordinate
	 * @return the item, or <code>null</code> if there is no item at the given
	 *         coordinates
	 */
	protected Item getItem(int x, int y) {
		return null;
	}
	/**
	 * Returns the children of the given parent without sorting and filtering
	 * them. The resulting array must not be modified, as it may come directly
	 * from the model's internal state.
	 * <p>
	 * Returns an empty array if the given parent is <code>null</code>.
	 * </p>
	 * 
	 * @param parent
	 *            the parent element
	 * @return the child elements
	 */
	protected Object[] getRawChildren(Object parent) {
		Object[] result = null;
		if (parent != null) {