Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/updatables/IdentityFunction.java
public static IUpdatableFunctionFactory getFactory() {
		if (factory == null) {
			factory = new IUpdatableFunctionFactory() {
				public IUpdatableFunction createFunction(IReadableSet domain) {
					return getInstance();
				}
			};
		}
		return factory;
	}
	
	public Object calculate(Object input) {
		return input;
	}
	public void addChangeListener(IChangeListener changeListener) {
	}
	public void removeChangeListener(IChangeListener changeListener) {
	}
	public void dispose() {
	}
	public boolean isStale() {
		return false;
	}
	
	public boolean isDisposed() {
		return false;
	}
}