Variability: Added syntax check for feature named

Feature names are now also checked for equality of keywords.

Issue-Ref: 3862
Issue-Url: af3#3862

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

org.fortiss.variability/src/org/fortiss/variability/util/.ratings

 FeatureModelTransformationUtils.java b38702296dcb48ff311b382bb9c05d2590e2dfac GREEN
 Pair.java 2dfd7dc65f7b9ba09a120f1a6058d1e8e9556a37 GREEN
-VariabilityUtils.java 1d84b70a1f26ee7b9df697fdc96b8e226762cb5d GREEN
+VariabilityUtils.java 68a8b79a3a6317a62a1ddaa048f127aec323d553 YELLOW
 VariabilityUtilsInternal.java 43d150214dd32e71f163bece306ad7661c2d5b4a GREEN

org.fortiss.variability/src/org/fortiss/variability/util/VariabilityUtils.java

@@ -156,8 +156,12 @@ public class VariabilityUtils {
 	 * @return Whether the given name is compatible with the presence condition systax.
 	 */
 	public static boolean isNameLegalInPresenceCondition(String literalName) {
+		if(literalName.equals("OR") || literalName.equals("AND") || literalName.equals("NOT") ||
+				literalName.equals("DEFAULT")) {
+			return false;
+		}
+
 		return literalName.matches(FEATURE_LITERAL_LEGAL_CHAR_REGEX + "*");
-		// TODO (#3862): Check for keywords.
 	}
 
 	/**