Bug 169637 [DataBinding] Multiple validation statuses per binding
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/ValueBinding.java
private final UpdateValueStrategy targetToModel;
	private final UpdateValueStrategy modelToTarget;
	private WritableValue validationStatusObservable;
	private IObservableValue target;
	private IObservableValue model;
	private boolean updatingTarget;
	private boolean updatingModel;
	private IValueChangeListener targetChangeListener = new IValueChangeListener() {
		public void handleValueChange(ValueChangeEvent event) {
			if (!updatingTarget) {
				doUpdate(target, model, targetToModel, false, false);
			}
		}
	};
	private IValueChangeListener modelChangeListener = new IValueChangeListener() {
		public void handleValueChange(ValueChangeEvent event) {
			if (!updatingModel) {
				doUpdate(model, target, modelToTarget, false, false);
			}
		}
	};
	/**
	 * @param targetObservableValue
	 * @param modelObservableValue
	 * @param targetToModel
	 * @param modelToTarget
	 */
	public ValueBinding(IObservableValue targetObservableValue,
			IObservableValue modelObservableValue,
			UpdateValueStrategy targetToModel, UpdateValueStrategy modelToTarget) {