replace ConditionEvent.addInvertedTo(..) by invert()

I do not see the advantage of encapsulating adding the event inside the `ConditionEvent`. On the other hand it provides a more flexible API if it is possible to simply retrieve the inverted event from a `ConditionEvent` and then decide as the caller what to do with it.

Signed-off-by: Peter Gafert <peter.gafert@tngtech.com>

archunit/src/main/java/com/tngtech/archunit/lang/ConditionEvent.java

@@ -27,8 +27,8 @@
 
 /**
  * An event that occurred while checking an {@link ArchCondition}. This can either be a {@link #isViolation() violation}
- * or be allowed. An event that is allowed will turn into a violation if it is
- * {@link #addInvertedTo(ConditionEvents) added inverted} to {@link ConditionEvents} (e.g. for negation of the rule).
+ * or be allowed. An event that is allowed will turn into a violation if it is {@link #invert() inverted}
+ * (e.g. for negation of the rule).
  */
 @PublicAPI(usage = INHERITANCE)
 public interface ConditionEvent {
@@ -38,15 +38,13 @@ public interface ConditionEvent {
     boolean isViolation();
 
     /**
-     * Adds the 'opposite' of the event. <br>
-     * E.g. <i>The event is a violation, if some conditions A and B are both true?</i>
-     * <br> {@literal ->} <i>The 'inverted' event is a violation if either A or B (or both) are not true</i><br>
-     * In the most simple case, this is just an equivalent event evaluating {@link #isViolation()}
-     * inverted.
-     *
-     * @param events The events to add the 'inverted self' to
+     * @return the 'opposite' of the event. <br>
+     *         Assume e.g. <i>The event is a violation, if some conditions A and B are both true</i>
+     *         <br> {@literal =>} <i>The 'inverted' event is a violation if either A or B (or both) are not true</i><br>
+     *         In the most simple case, this is just an equivalent event evaluating {@link #isViolation()}
+     *         inverted.
      */
-    void addInvertedTo(ConditionEvents events);
+    ConditionEvent invert();
 
     /**
      * @return A textual description of this event as a list of lines

archunit/src/main/java/com/tngtech/archunit/lang/EvaluationResult.java

@@ -184,8 +184,8 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
-            delegate.addInvertedTo(events);
+        public ConditionEvent invert() {
+            return new FilteredEvent(delegate.invert(), linePredicate);
         }
 
         @Override

archunit/src/main/java/com/tngtech/archunit/lang/SimpleConditionEvent.java

@@ -44,8 +44,8 @@ public boolean isViolation() {
     }
 
     @Override
-    public void addInvertedTo(ConditionEvents events) {
-        events.add(new SimpleConditionEvent(correspondingObject, !conditionSatisfied, message));
+    public ConditionEvent invert() {
+        return new SimpleConditionEvent(correspondingObject, !conditionSatisfied, message);
     }
 
     @Override

archunit/src/main/java/com/tngtech/archunit/lang/conditions/AndCondition.java

@@ -44,8 +44,8 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
-            events.add(new OrConditionEvent<>(correspondingObject, invert(evaluatedConditions)));
+        public ConditionEvent invert() {
+            return new OrConditionEvent<>(correspondingObject, invert(evaluatedConditions));
         }
 
         @Override

archunit/src/main/java/com/tngtech/archunit/lang/conditions/ContainAnyCondition.java

@@ -72,8 +72,8 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
-            events.add(new OnlyConditionEvent(correspondingObjects, violating, allowed));
+        public ConditionEvent invert() {
+            return new OnlyConditionEvent(correspondingObjects, violating, allowed);
         }
 
         @Override

archunit/src/main/java/com/tngtech/archunit/lang/conditions/ContainsOnlyCondition.java

@@ -71,8 +71,8 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
-            events.add(new AnyConditionEvent(correspondingObjects, violating, allowed));
+        public ConditionEvent invert() {
+            return new AnyConditionEvent(correspondingObjects, violating, allowed);
         }
 
         @Override

archunit/src/main/java/com/tngtech/archunit/lang/conditions/JoinCondition.java

@@ -132,7 +132,7 @@ private ConditionWithEvents<T> invert(ConditionWithEvents<T> evaluation) {
             Stream.concat(
                     evaluation.events.getAllowed().stream(),
                     evaluation.events.getViolating().stream()
-            ).forEach(event -> event.addInvertedTo(invertedEvents));
+            ).forEach(event -> invertedEvents.add(event.invert()));
             return new ConditionWithEvents<>(evaluation.condition, invertedEvents);
         }
     }

archunit/src/main/java/com/tngtech/archunit/lang/conditions/NeverCondition.java

@@ -56,7 +56,7 @@ private static class InvertingConditionEvents extends DelegatingConditionEvents
 
         @Override
         public void add(ConditionEvent event) {
-            event.addInvertedTo(delegate);
+            delegate.add(event.invert());
         }
     }
 }

archunit/src/main/java/com/tngtech/archunit/lang/conditions/OrCondition.java

@@ -20,7 +20,9 @@
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableList;
 import com.tngtech.archunit.lang.ArchCondition;
+import com.tngtech.archunit.lang.ConditionEvent;
 import com.tngtech.archunit.lang.ConditionEvents;
+import com.tngtech.archunit.lang.conditions.AndCondition.AndConditionEvent;
 
 import static java.util.Collections.singleton;
 
@@ -45,8 +47,8 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
-            events.add(new AndCondition.AndConditionEvent<>(correspondingObject, invert(evaluatedConditions)));
+        public ConditionEvent invert() {
+            return new AndConditionEvent<>(correspondingObject, invert(evaluatedConditions));
         }
 
         @Override

archunit/src/test/java/com/tngtech/archunit/lang/EvaluationResultTest.java

@@ -169,7 +169,7 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
+        public ConditionEvent invert() {
             throw new UnsupportedOperationException("Implement me");
         }
 

archunit/src/test/java/com/tngtech/archunit/library/freeze/FreezingArchRuleTest.java

@@ -629,7 +629,7 @@ public boolean isViolation() {
         }
 
         @Override
-        public void addInvertedTo(ConditionEvents events) {
+        public ConditionEvent invert() {
             throw new UnsupportedOperationException("Implement me");
         }