Fix Missing rule verifier for string values

dmnverifierapi/src/main/java/de/unikoblenz/fgbks/base/utils/boundary/bicreater/BiCreaterStringLowerBounds.java

 package de.unikoblenz.fgbks.base.utils.boundary.bicreater;
 
 import static de.unikoblenz.fgbks.base.utils.boundary.checker.BoundaryCheckType.IS_EQUAL;
-import static de.unikoblenz.fgbks.base.utils.boundary.checker.BoundaryCheckType.IS_NOT_IN_CONTACT;
+import static de.unikoblenz.fgbks.base.utils.boundary.checker.BoundaryCheckType.SUBSUMES;
 
 import de.unikoblenz.fgbks.base.utils.boundary.impl.StringBoundary;
 import java.util.Arrays;
@@ -11,8 +11,11 @@ import java.util.Set;
 
 /**
  * The lower bound creator implementation of {@link BoundaryBiCreaterType#LOWER_BOUNDS} for {@link
- * StringBoundary}. <br> The result is a new boundary with the lower bounds, or an empty optional,
- * if the creation is not possible. <br> In: {@code b1: "a","b"; b2: "a"}<br> Out: {@code "b"} <br>
+ * StringBoundary}. <br>
+ * The result is a new boundary with the lower bounds, or an empty optional, if the creation is not
+ * possible. <br>
+ * In: {@code b1: "a"; b2: "a", "b"}<br>
+ * Out: {@code "b"} <br>
  */
 public class BiCreaterStringLowerBounds extends AbstractBoundaryBiCreater<StringBoundary> {
 
@@ -38,17 +41,47 @@ public class BiCreaterStringLowerBounds extends AbstractBoundaryBiCreater<String
 
   @Override
   public Optional<StringBoundary> create(StringBoundary b1, StringBoundary b2) {
-    if (b1.checkWith(IS_NOT_IN_CONTACT, b2) || b1.checkWith(IS_EQUAL, b2)) {
+    if (b2.matchesAny()) {
       return Optional.empty();
     }
-    if (b1.matchesAny() || b1.matchesNoneOfValues()) {
+    if (b1.matchesAny()) {
+      return Optional.of(
+          StringBoundary.getBuilder()
+              .matchesNoneOfValues(!b2.matchesNoneOfValues())
+              .addValues(b2.getValues())
+              .build());
+    }
+
+    if (b2.checkWith(IS_EQUAL, b1) || b2.checkWith(SUBSUMES, b1)) {
+      return Optional.empty();
+    }
+
+    if (b1.matchesNoneOfValues()) {
+      if (b2.matchesNoneOfValues()) {
+        Set<String> values = new HashSet<>(Arrays.asList(b2.getValues()));
+        values.removeAll(Arrays.asList(b1.getValues()));
+        if (values.size() == 0) {
+          return Optional.empty();
+        }
+        return Optional.of(StringBoundary.getBuilder().addValues(values).build());
+      } else {
+        return Optional.of(
+            StringBoundary.getBuilder()
+                .matchesNoneOfValues(true)
+                .addValues(b1.getValues())
+                .addValues(b2.getValues())
+                .build());
+      }
+    }
+
+    if (b2.matchesNoneOfValues()) {
       return Optional.of(
           StringBoundary.getBuilder()
               .addValues(b1.getValues())
               .addValues(b2.getValues())
-              .matchesNoneOfValues(!b2.matchesNoneOfValues())
               .build());
     }
+
     Set<String> values = new HashSet<>(Arrays.asList(b1.getValues()));
     values.removeAll(Arrays.asList(b2.getValues()));
     return Optional.of(StringBoundary.getBuilder().addValues(values).build());