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
if (!newSelection.equals(oldSelection))
				handleInvalidSelection(oldSelection, newSelection);
		}
	}
	/*
	 * Non-Javadoc. Method declared on Viewer.
	 */
	public void refresh() {
		refresh(getRoot());
	}
	/**
	 * Refreshes this viewer with information freshly obtained from this
	 * viewer's model. If <code>updateLabels</code> is <code>true</code>
	 * then labels for otherwise unaffected elements are updated as well.
	 * Otherwise, it assumes labels for existing elements are unchanged, and
	 * labels are only obtained as needed (for example, for new elements).
	 * <p>
	 * Calling <code>refresh(true)</code> has the same effect as
	 * <code>refresh()</code>.
	 * <p>
	 * Note that the implementation may still obtain labels for existing
	 * elements even if <code>updateLabels</code> is false. The intent is
	 * simply to allow optimization where possible.
	 * 
	 * @param updateLabels
	 *            <code>true</code> to update labels for existing elements,
	 *            <code>false</code> to only update labels as needed, assuming
	 *            that labels for existing elements are unchanged.
	 * 
	 * @since 2.0