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
/**
	 * Updates the given elements' presentation when one or more of their
	 * properties change. Only the given elements are updated.
	 * <p>
	 * This does not handle structural changes (e.g. addition or removal of
	 * elements), and does not update any other related elements (e.g. child
	 * elements). To handle structural changes, use the <code>refresh</code>
	 * methods instead.
	 * </p>
	 * <p>
	 * This should be called when an element has changed in the model, in order
	 * to have the viewer accurately reflect the model. This method only affects
	 * the viewer, not the model.
	 * </p>
	 * <p>
	 * Specifying which properties are affected may allow the viewer to optimize
	 * the update. For example, if the label provider is not affected by changes
	 * to any of these properties, an update may not actually be required.
	 * Specifing <code>properties</code> as <code>null</code> forces a full
	 * update of the given elements.
	 * </p>
	 * <p>
	 * If the viewer has a sorter which is affected by a change to one of the
	 * properties, the elements' positions are updated to maintain the sort
	 * order.
	 * </p>
	 * <p>
	 * If the viewer has a filter which is affected by a change to one of the
	 * properties, elements may appear or disappear if the change affects
	 * whether or not they are filtered out.