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
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/DataBindingContext.java
import org.eclipse.jface.databinding.observable.list.IObservableList;
import org.eclipse.jface.databinding.observable.list.ObservableList;
import org.eclipse.jface.databinding.observable.list.WritableList;
import org.eclipse.jface.databinding.observable.value.ComputedValue;
import org.eclipse.jface.databinding.observable.value.IObservableValue;
import org.eclipse.jface.internal.databinding.internal.ListBinding;
import org.eclipse.jface.internal.databinding.internal.ValidationErrorList;
import org.eclipse.jface.internal.databinding.internal.ValueBinding;
import org.eclipse.jface.internal.databinding.provisional.conversion.IConverter;
import org.eclipse.jface.internal.databinding.provisional.factories.BindSupportFactory;
import org.eclipse.jface.internal.databinding.provisional.factories.DefaultBindSupportFactory;
import org.eclipse.jface.internal.databinding.provisional.validation.IDomainValidator;
import org.eclipse.jface.internal.databinding.provisional.validation.IValidator;
import org.eclipse.jface.internal.databinding.provisional.validation.ValidationError;
/**
 * A context for binding observable objects. This class is not intended to be
 * subclassed by clients.
 * 
 * <p>
 * <strong>EXPERIMENTAL</strong>. This class or interface has been added as
 * part of a work in progress. There is no guarantee that this API will remain
 * unchanged during the 3.2 release cycle. Please do not use this API without
 * consulting with the Platform/UI team.
 * </p>
 * 
 * @since 1.1
 * 
 */
public class DataBindingContext {
	/**