Bug 140644 [DataBinding] Binding to ValidationError of DataBindingContext is broken
Hello, I wanted to bind the ValidationError Observable to a Widget, and it doesn't seem to work. I tested with Jface Databinding sample and in TestMasterDetails.java example, instead of binding the simple date error to a label, I bound the ValidationError of DBC to the Label (with a simple converter). dbc.bind(validationError, dbc.getValidationError(), new BindSpec().setUpdateModel(false).setModelToTargetConverter(new IConverter() { public Object convert(Object fromObject) { // TODO Auto-generated method stub if (fromObject == null) return null; return ((ValidationError) fromObject).message; } public Object getFromType() { // TODO Auto-generated method stub return Object.class; } public Object getToType() { // TODO Auto-generated method stub return String.class; } })); After investigating, I saw the ValidationError is a computed value (very interesting concept and useful) on the ValidationErrorList. 1. The ComputedValue mechanism seems to use the StateListener to the Object, but I don't see any management of staleness in ValidationErrorList (or ObservableList). 2. When one of the field gets an error, I debug and saw the ChangedListener on my binding was null (whereas the ValidationErrorList registers listeners on them). At the beginning, it's registered, the removed and not added again when needed. I have not enough time to go deeper in the mechanism, could you help me to understand what I'm doing wrong with this simple binding (With previous releases I was already binding with that mechanism and it worked). Is there an other way to do this? (My workaround is a listener on DBC, but I would prefer to use ValidationError Computed value). Thanks in advance
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/jface/tests/databinding/DatabindingContextTest.java
assertEquals(
				"Both binding events should be called the same number of times",
				calls[0], calls[1]);
		assertEquals(o2, settableValue1.getValue());
		
		binding.addBindingEventListener(new BindingAdapter() {
			public ValidationError bindingEvent(BindingEvent e) {
				if (e.pipelinePosition == org.eclipse.jface.databinding.BindingEvent.PIPELINE_AFTER_CONVERT) {
					return ValidationError.error("error");
				}
				return null;
			}
		});
		settableValue1.setValue(o1);
		settableValue2.setValue(o2);
		assertEquals(
				"Both binding events should be called the same number of times",
				calls[0], calls[1]);
		assertEquals("binding events should be called at least once", true,
				calls[0] > 0);
	}
	public void testCollectionBindingListeners() {
		WritableList v1 = new WritableList();
		WritableList v2 = new WritableList();
		Binding binding = dbc.bind(v1, v2, null);
		final int[] calls = new int[] { 0 };
		binding.addBindingEventListener(new BindingAdapter() {
			public ValidationError bindingEvent(BindingEvent e) {
				calls[0]++;
				return null;