Added tooltip for feature model

Issue-ref: 4277
Issue-URL: #4277



Signed-off-by: Andreas Bayha <bayha@fortiss.org>

org.fortiss.af3.variability.featuremodel.ui/src/org/fortiss/af3/variability/featuremodel/ui/editor/fx/FeatureModelFXEditorUIProvider.java

@@ -33,6 +33,7 @@ import org.fortiss.af3.variability.featuremodel.model.CompositionalFeature;
 import org.fortiss.af3.variability.featuremodel.model.CrossFeatureConstraint;
 import org.fortiss.tooling.common.ui.javafx.control.treetableview.DynamicTreeTableUIProviderBase;
 import org.fortiss.tooling.kernel.model.INamedCommentedElement;
+import org.fortiss.tooling.kernel.model.INamedElement;
 import org.fortiss.tooling.kernel.service.ICommandStackService;
 import org.fortiss.tooling.kernel.ui.service.IModelElementHandlerService;
 import org.fortiss.variability.model.IHasName;
@@ -279,4 +280,43 @@ public class FeatureModelFXEditorUIProvider extends DynamicTreeTableUIProviderBa
 				newValue == null ? EMPTY : new StructuredSelection(newValue);
 		editor.getSite().getSelectionProvider().setSelection(selection);
 	}
+
+	/** {@inheritDoc} */
+	@Override
+	public String getTooltip(IHasName element, int column) {
+		if(column == COL_IDX_FEATURE_NAME) {
+			if(element instanceof CompositionalFeature) {
+				final String parentName = ((INamedElement)element.eContainer()).getName();
+
+				if(element.eContainer() instanceof AlternativeFeature) {
+					return "This is one alternative that can be selected for \"" + parentName +
+							"\" for the instantiation of the SPL.";
+				}
+
+				String tip = "";
+
+				final CompositionalFeature feature = (CompositionalFeature)element;
+				if(feature.getSubFeatures().size() > 0) {
+					tip = "This OR feature enables an arbitrary number of optional sub-features to be selected for the instantiation of the SPL. ";
+				}
+				if(feature.isOptional()) {
+					tip += "\nThis feature can optionally be selected for the instantiation of the SPL. ";
+				} else {
+					tip += "\nThis feature is mandatroy for all configurations in which the parent feature \"" +
+							parentName +
+							"\" is selected. Select \"isOptional\" in the Properties view to make it optional. ";
+				}
+
+				return tip;
+			}
+			if(element instanceof AlternativeFeature) {
+				return "This XOR feature requires to select exactly one sub-feature to be selected for the instantiation of the SPL.";
+			}
+			if(element instanceof CrossFeatureConstraint) {
+				return "This constraint restricts which combination with another feature is a legal selection for the instantiation of the SPL.";
+			}
+		}
+
+		return super.getTooltip(element, column);
+	}
 }