Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/ValueBinding.java
validator = bindSpec.getValidator();
		if (validator == null) {
			throw new BindingException("Missing validator"); 
		}
		domainValidator = bindSpec.getDomainValidator();
		target.addChangeListener(targetChangeListener);
		model.addChangeListener(modelChangeListener);
	}
	private final IChangeListener targetChangeListener = new IChangeListener() {
		public void handleChange(ChangeEvent changeEvent) {
			if (updating) 
				return;
			if (changeEvent.getChangeType() == ChangeEvent.VERIFY) {
				
				
				Object value = changeEvent.getNewValue();
				String partialValidationError = validator
						.isPartiallyValid(value);
				context.updatePartialValidationError(this,
						partialValidationError);
				if (partialValidationError != null) {
					changeEvent.setVeto(true);
				}
			} else if (changeEvent.getChangeType() == ChangeEvent.CHANGE) {
				
				
				updateModelFromTarget(changeEvent);
			}
		}
	};