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
* </p>
	 * 
	 * @param item
	 * @param element element
	 * @param fullMap
	 *            <code>true</code> if mappings are added and removed, and
	 *            <code>false</code> if only the new map gets installed
	 */
	protected abstract void doUpdateItem(Widget item, Object element, boolean fullMap);
	/**
	 * Compares two elements for equality. Uses the element comparer if one has
	 * been set, otherwise uses the default <code>equals</code> method on the
	 * elements themselves.
	 * 
	 * @param elementA
	 *            the first element
	 * @param elementB
	 *            the second element
	 * @return whether elementA is equal to elementB
	 */
	protected boolean equals(Object elementA, Object elementB) {
		if (comparer == null)
			return elementA == null ? elementB == null : elementA.equals(elementB);
		else
			return elementA == null ? elementB == null : comparer.equals(elementA, elementB);
	}
	/**
	 * Returns the result of running the given elements through the filters.
	 * 
	 * @param elements