Bug 118429 [DataBinding] Validation should use IStatus, not just Strings
In order to use data binding in Workbench or IDE dialogs and preference pages, we need validation in terms of IStatus objects. Using strings is too simplistic. For example, look at the wizard for creating a new class. You will get a warning if the class name does not start with an uppercase letter, or if you don't provide a package name, but you will still be able to click "Finish" to proceed anyway. (Note that IStatus is currently not on the classpath, we need to re-introduce the dependency on org.eclipse.equinox.common, which contains IStatus etc.)
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/observable/Diffs.java
}
	/**
	 * @param oldValue
	 * @param newValue
	 * @return a value diff
	 */
	public static ValueDiff createValueDiff(final Object oldValue,
			final Object newValue) {
		return new ValueDiff() {
			public Object getOldValue() {
				return oldValue;
			}
			public Object getNewValue() {
				return newValue;
			}
		};
	}
	/**
	 * @param additions
	 * @param removals
	 * @return a set diff
	 */
	public static SetDiff createSetDiff(Set additions, Set removals) {
		final Set unmodifiableAdditions = Collections
				.unmodifiableSet(additions);
		final Set unmodifiableRemovals = Collections.unmodifiableSet(removals);
		return new SetDiff() {
			public Set getAdditions() {
				return unmodifiableAdditions;
			}