Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/updatables/ListToSetAdapter.java
Object added = changeEvent.getNewValue();
				if (!elements.contains(added)) {
					elements.add(added);
					fireAdded(Collections.singleton(added));
				}
				break;
			case ChangeEvent.REMOVE:
				Object removed = changeEvent.getNewValue();
				if (elements.contains(removed)) {
					elements.remove(removed);
					fireRemoved(Collections.singleton(removed));
				}
				break;
				
			case ChangeEvent.STALE:
				fireStale(input.isStale());
				break;
			}
		}
	};
	
	public ListToSetAdapter(IReadableList input) {
		Assert.isNotNull(input);
		this.input = input;
	}
	
	public boolean isStale() {
		return input.isStale();
	}