Annotations: Simplify value retrieval

* The intended way to obtain annotation values by providers requires
  lots of boilerplate code.
* Provide a util method therefore.
* Remove the exception marker for the getAnnotatedValue method as it
  has not been used since ~3 years...

Issue-Ref: 3750
Issue-Url: https://af3-developer.fortiss.org/issues/3750


Signed-off-by: Alexander Diewald <diewald@fortiss.org>

org.fortiss.tooling.base/src/org/fortiss/tooling/base/annotation/valueprovider/.ratings

 AnnotationInstSpec.java b4f2ed47a8984e751e04049de5bdb3cad2c0a933 GREEN
-DerivedAnnotationValueProviderBase.java 15da44b7b92b7fd351aa48422ff5957a2ce34e35 GREEN
+DerivedAnnotationValueProviderBase.java afedd21d3469127bbb20adb34c191b5c9c980f6c YELLOW
 EStructuralFeatureDescriptor.java 2e14df3830d854bc1693382727b2033b23d0051c GREEN
-EStructuralFeatureValueProviderBase.java 71c418486bc6c46bc468e18c92b21f6b537706db GREEN
-IAnnotationValueProvider.java d093cb522e7c484420331f0c77690bebe7e131b4 GREEN
+EStructuralFeatureValueProviderBase.java 287facbbce47c16d892bae82a214f64ceeef2263 YELLOW
+IAnnotationValueProvider.java 08e0e5f66dc97865e9ac03e1ac646af332845e14 YELLOW
 ValueProviderBase.java e4e866840845346ec99a4304048f5327c4890996 GREEN

org.fortiss.tooling.base/src/org/fortiss/tooling/base/annotation/valueprovider/DerivedAnnotationValueProviderBase.java

@@ -98,7 +98,7 @@ public abstract class DerivedAnnotationValueProviderBase<T extends IDerivedAnnot
 	/** {@inheritDoc} */
 	@SuppressWarnings("unchecked")
 	@Override
-	public <U> U getAnnotationValue(T specification) throws Exception {
+	public <U> U getAnnotationValue(T specification) {
 		U calculatedValue = (U)specification.getValue();
 		if(calculatedValue != null) {
 			return calculatedValue;

org.fortiss.tooling.base/src/org/fortiss/tooling/base/annotation/valueprovider/EStructuralFeatureValueProviderBase.java

@@ -280,7 +280,7 @@ public abstract class EStructuralFeatureValueProviderBase<T extends IAnnotatedSp
 	/** {@inheritDoc} */
 	@SuppressWarnings("unchecked")
 	@Override
-	public <U> U getAnnotationValue(T specification) throws Exception {
+	public <U> U getAnnotationValue(T specification) {
 		return (U)specification
 				.eGet(getEStructuralFeatureDescriptor().getEStructuralFeature(specification));
 	}

org.fortiss.tooling.base/src/org/fortiss/tooling/base/annotation/valueprovider/IAnnotationValueProvider.java

@@ -64,10 +64,10 @@ public interface IAnnotationValueProvider<T extends IAnnotatedSpecification>
 	public class AnnotationActionEntry {
 		/** Scope defining the {@link AnnotationEntry}s to apply the corresponding action to. */
 		public enum ActionScope {
-		/** All {@link AnnotationEntry}s that are matching the selected filter. */
-		ALL_VISIBLE_ITEMS,
-		/** Apply the action only to the selected item. */
-		SINGLE_ITEM
+			/** All {@link AnnotationEntry}s that are matching the selected filter. */
+			ALL_VISIBLE_ITEMS,
+			/** Apply the action only to the selected item. */
+			SINGLE_ITEM
 		}
 
 		/** Name of the associated action, i.e. its entry. */
@@ -292,7 +292,7 @@ public interface IAnnotationValueProvider<T extends IAnnotatedSpecification>
 	public boolean canEdit(T specification);
 
 	/** Returns the value of the annotation. */
-	public <U> U getAnnotationValue(T specification) throws Exception;
+	public <U> U getAnnotationValue(T specification);
 
 	/**
 	 * Sets a new value for the annotation.

org.fortiss.tooling.base/src/org/fortiss/tooling/base/utils/.ratings

 AngleUtils.java 462551eae71738ff51f92c9906bff9a21a375d2b GREEN
-AnnotationUtils.java 41e25bcdd2906f7fa511223a20cbd09a1391a23c GREEN
+AnnotationUtils.java 1da750d19d92658b0bdf6bc18ceb18aa667e557b YELLOW
 BaseMathUtils.java 65f6c39b641cba3c984a38f42b1bbf7dbf3287a3 GREEN
 BaseModelElementUtils.java b8775b7a462efc168cf79a017aa3377a782d10f6 GREEN
 ConstraintsBaseUtils.java bba938b43756ce6f35c338f6cef21c3ab5d49a9d GREEN

org.fortiss.tooling.base/src/org/fortiss/tooling/base/utils/AnnotationUtils.java

@@ -85,6 +85,24 @@ public class AnnotationUtils {
 		modelElement.getSpecifications().add(newAnnotation);
 	}
 
+	/**
+	 * Returns the value of type {@code U} specified for the given {@link IModelElement} by the
+	 * given annotation {@code clazz}.
+	 */
+	public static <T extends IAnnotatedSpecification, U> U
+			getAnnotationValue(IModelElement modelElement, Class<T> clazz, Class<U> valueType) {
+		IAnnotationValueProvider<T> annValProvider =
+				getAnnotationValueProvider(modelElement, clazz);
+		T annotation = getAnnotation(modelElement, clazz);
+		U value = annValProvider.getAnnotationValue(annotation);
+		if(value != null && !valueType.isAssignableFrom(value.getClass())) {
+			throw new IllegalArgumentException("The value of the annotation " +
+					clazz.getSimpleName() + " of the model element " + modelElement +
+					" is not of the expected type " + valueType.getSimpleName());
+		}
+		return value;
+	}
+
 	/**
 	 * <p>
 	 * Returns the annotation of a given {@code Class<T>} from a given {@code modelElement}. If the
@@ -150,10 +168,11 @@ public class AnnotationUtils {
 	 *            Annotation type.
 	 * @return The corresponding value provider or {@code null} if none is found.
 	 */
-	public static IAnnotationValueProvider<IAnnotatedSpecification> getAnnotationValueProvider(
-			IModelElement element, Class<IAnnotatedSpecification> annotationType) {
+	@SuppressWarnings("unchecked")
+	public static <T extends IAnnotatedSpecification> IAnnotationValueProvider<T>
+			getAnnotationValueProvider(IModelElement element, Class<T> annotationType) {
 		AnnotationEntry annEntry = AnnotationValueService.getInstance().getAnnotationEntry(element);
-		return annEntry.getAnnotationValueProvider(annotationType);
+		return (IAnnotationValueProvider<T>)annEntry.getAnnotationValueProvider(annotationType);
 	}
 
 	/**