Correct doSet() signature in UpdateValueStrategy

The "value" that is passed as to the doSet() method must match the
source type, not the target type. Otherwise a ClassCastException is
thrown when a typified UpdateValueStrategy is used.

Example:

IObservableValue<Integer> source = ...
IObservableValue<Boolean> target = ...
UpdateValueStrategy<Integer, Boolean> strategy = ...

context.bindValue(target, source, null, strategy);

A change to "source" will always produce a ClassCastException, because
an Integer is passed to the doSet() method, which is then casted to a
Boolean by the Java runtime. This renders the strategy unusable, unless
raw types are used.

Closes #3008

Author: ptziegler

bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/UpdateValueStrategy.java

@@ -476,9 +476,10 @@ public IStatus validateBeforeSet(D value) {
 	 * @param value           new value to set
 	 * @return status
 	 */
-	protected IStatus doSet(IObservableValue<? super D> observableValue, D value) {
+	@SuppressWarnings("unchecked")
+	protected IStatus doSet(IObservableValue<? super D> observableValue, S value) {
 		try {
-			observableValue.setValue(value);
+			observableValue.setValue((D) value);
 		} catch (Exception ex) {
 			return logErrorWhileSettingValue(ex);
 		}

bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/ValueBinding.java

@@ -203,7 +203,7 @@ private <S, D1, D2 extends D1> void doUpdate(final IObservableValue<S> source,
 						updatingModel = true;
 					}
 					try {
-						IStatus setterStatus = updateValueStrategy.doSet(destination, convertedValue);
+						IStatus setterStatus = updateValueStrategy.doSet(destination, value);
 
 						mergeStatus(multiStatus, setterStatus);
 					} finally {

examples/org.eclipse.jface.examples.databinding/src/org/eclipse/jface/examples/databinding/nestedselection/TestMasterDetail.java

@@ -59,7 +59,7 @@ public class TestMasterDetail {
 	 */
 	private static final class CustomUpdateValueStrategy<S, D> extends UpdateValueStrategy<S, D> {
 		@Override
-		protected IStatus doSet(IObservableValue<? super D> observableValue, D value) {
+		protected IStatus doSet(IObservableValue<? super D> observableValue, S value) {
 			IStatus result = super.doSet(observableValue, value);
 			if (result.isOK()) {
 				Object changed = observableValue;

tests/org.eclipse.jface.tests.databinding/src/org/eclipse/core/tests/databinding/UpdateValueStrategyTest.java

@@ -15,6 +15,7 @@
 
 package org.eclipse.core.tests.databinding;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertThrows;
@@ -25,6 +26,7 @@
 import java.util.Date;
 
 import org.eclipse.core.databinding.BindingException;
+import org.eclipse.core.databinding.DataBindingContext;
 import org.eclipse.core.databinding.UpdateValueStrategy;
 import org.eclipse.core.databinding.observable.value.IObservableValue;
 import org.eclipse.core.databinding.observable.value.WritableValue;
@@ -44,6 +46,8 @@
 import org.eclipse.core.internal.databinding.validation.StringToIntegerValidator;
 import org.eclipse.core.internal.databinding.validation.StringToLongValidator;
 import org.eclipse.core.internal.databinding.validation.StringToShortValidator;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.tests.databinding.AbstractDefaultRealmTestCase;
 import org.junit.Test;
 
@@ -181,6 +185,43 @@ public void testDefaultValidatorForNumberToBigDecimal() throws Exception {
 				NumberToUnboundedNumberValidator.class);
 	}
 
+	@Test
+	public void testUpdateValueWithStrategy() throws Exception {
+		WritableValue<Integer> model = WritableValue.withValueType(Integer.class);
+		WritableValue<Boolean> target = WritableValue.withValueType(Boolean.class);
+
+		/*
+		UpdateValueStrategy strategy1 = new UpdateValueStrategy() {
+			@Override
+			protected IStatus doSet(IObservableValue observableValue, Object value) {
+				Integer modelValue = (Integer) value;
+				if (modelValue != null && modelValue != 0) {
+					return super.doSet(observableValue, true);
+				}
+				return super.doSet(observableValue, false);
+			}
+		};
+		*/
+
+		UpdateValueStrategy<Integer, Boolean> strategy2 = new UpdateValueStrategy<>() {
+			@Override
+			protected IStatus doSet(IObservableValue<? super Boolean> observableValue, Integer value) {
+				if (value != null && value != 0) {
+					observableValue.setValue(true);
+				} else {
+					observableValue.setValue(false);
+				}
+				return Status.OK_STATUS;
+			}
+		};
+
+		DataBindingContext context = new DataBindingContext();
+		context.bindValue(target, model, null, strategy2);
+
+		model.setValue(1);
+		assertEquals(target.getValue(), true);
+	}
+
 	@Test
 	public void testCachesDefaultedValidators() throws Exception {
 		WritableValue<String> source = WritableValue.withValueType(String.class);

tests/org.eclipse.jface.tests.databinding/src/org/eclipse/core/tests/databinding/ValueBindingTest.java

@@ -189,7 +189,7 @@ public void testCancelStatusInValidationDoesNotUpdateModel()
 	public void testStatusesFromEveryPhaseAreReturned() throws Exception {
 		UpdateValueStrategy<Object, String> strategy = new UpdateValueStrategy<>() {
 			@Override
-			protected IStatus doSet(IObservableValue<? super String> observableValue, String value) {
+			protected IStatus doSet(IObservableValue<? super String> observableValue, Object value) {
 				super.doSet(observableValue, value);
 				return ValidationStatus.info("");
 			}