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/TableViewer.java
* Returns the column properties of this table viewer. The properties must
	 * correspond with the columns of the table control. They are used to
	 * identify the column in a cell modifier.
	 * 
	 * @return the list of column properties
	 */
	public Object[] getColumnProperties() {
		return tableViewerImpl.getColumnProperties();
	}
	/*
	 *  (non-Javadoc)
	 * @see org.eclipse.jface.viewers.Viewer#getControl()
	 */
	public Control getControl() {
		return table;
	}
	/**
	 * Returns the element with the given index from this table viewer. Returns
	 * <code>null</code> if the index is out of range.
	 * <p>
	 * This method is internal to the framework.
	 * </p>
	 * 
	 * @param index
	 *            the zero-based index
	 * @return the element at the given index, or <code>null</code> if the
	 *         index is out of range
	 */
	public Object getElementAt(int index) {
		if (index >= 0 && index < table.getItemCount()) {