MID-7008: Added early exit to diff* methods in case they are used via…

… equals

In order to determine if objects are equals, we do not need full diff of objects
only to know that they are different.
Adds optional exit of diff methods on first occurence of different value.

infra/prism-impl/src/main/java/com/evolveum/midpoint/prism/impl/ItemImpl.java

@@ -586,8 +586,18 @@ public ItemDelta<V,D> diff(Item<V,D> other, @NotNull ParameterizedEquivalenceStr
 
     void diffInternal(Item<V, D> other, Collection<? extends ItemDelta> deltas, boolean rootValuesOnly,
             ParameterizedEquivalenceStrategy strategy) {
+        diffInternal(other, deltas, rootValuesOnly, strategy, false);
+    }
+
+    boolean diffInternal(Item<V, D> other, Collection<? extends ItemDelta> deltas, boolean rootValuesOnly,
+            ParameterizedEquivalenceStrategy strategy, boolean exitOnDiff) {
         ItemDelta delta = createDelta();
         if (other == null) {
+            // Early exit for equals use case
+            if (exitOnDiff) {
+                return true;
+            }
+
             if (delta.getDefinition() == null && this.getDefinition() != null) {
                 delta.setDefinition(this.getDefinition().clone());
             }
@@ -611,7 +621,11 @@ void diffInternal(Item<V, D> other, Collection<? extends ItemDelta> deltas, bool
                     if (!rootValuesOnly && thisValue.representsSameValue(otherValue, true)) {
                         found = true;
                         // Matching IDs, look inside to figure out internal deltas
-                        ((PrismValueImpl) thisValue).diffMatchingRepresentation(otherValue, deltas, strategy);
+                        boolean different = ((PrismValueImpl) thisValue).diffMatchingRepresentation(otherValue, deltas, strategy, exitOnDiff);
+                        if (exitOnDiff && different) {
+                            return true;
+                        }
+
                         // No need to process this value again
                         iterator.remove();
                         break;
@@ -624,12 +638,18 @@ void diffInternal(Item<V, D> other, Collection<? extends ItemDelta> deltas, bool
                     }
                 }
                 if (!found) {
+                    if (exitOnDiff) {
+                        return true;
+                    }
                     // We have the value and the other does not, this is delete of the entire value
                     delta.addValueToDelete(thisValue.clone());
                 }
             }
             // outstandingOtherValues are those values that the other has and we could not
             // match them to any of our values. These must be new values to add
+            if (exitOnDiff && !outstandingOtherValues.isEmpty()) {
+                return true;
+            }
             for (PrismValue outstandingOtherValue : outstandingOtherValues) {
                 delta.addValueToAdd(outstandingOtherValue.clone());
             }
@@ -640,6 +660,7 @@ void diffInternal(Item<V, D> other, Collection<? extends ItemDelta> deltas, bool
         if (delta != null && !delta.isEmpty()) {
             ((Collection)deltas).add(delta);
         }
+        return !delta.isEmpty();
     }
 
     protected ItemDelta<V,D> fixupDelta(ItemDelta<V, D> delta, Item<V, D> other) {