chore: less changes

core/src/main/java/ai/timefold/solver/core/impl/domain/variable/ExternalizedListVariableStateSupply.java

@@ -8,7 +8,6 @@
 import ai.timefold.solver.core.impl.domain.variable.nextprev.PreviousElementShadowVariableDescriptor;
 import ai.timefold.solver.core.impl.score.director.InnerScoreDirector;
 import ai.timefold.solver.core.preview.api.domain.metamodel.ElementLocation;
-import ai.timefold.solver.core.preview.api.domain.metamodel.LocationInList;
 
 import org.jspecify.annotations.NonNull;
 
@@ -129,11 +128,6 @@ public ElementLocation getLocationInList(Object planningValue) {
         return listVariableState.getLocationInList(planningValue);
     }
 
-    @Override
-    public LocationInList getNextLocationInList(Object planningValue) {
-        return listVariableState.getNextLocationInList(planningValue);
-    }
-
     @Override
     public Integer getIndex(Object planningValue) {
         return listVariableState.getIndex(planningValue);

core/src/main/java/ai/timefold/solver/core/impl/domain/variable/ListVariableState.java

@@ -222,24 +222,6 @@ public ElementLocation getLocationInList(Object planningValue) {
         }
     }
 
-    public LocationInList getNextLocationInList(Object planningValue) {
-        if (requiresLocationMap) {
-            var mutableLocationInList = elementLocationMap.get(planningValue);
-            if (mutableLocationInList == null) {
-                throw new IllegalArgumentException("The element (%s) is not assigned (%s)."
-                        .formatted(planningValue, sourceVariableDescriptor));
-            }
-            return ElementLocation.of(mutableLocationInList.getEntity(), mutableLocationInList.getIndex() + 1);
-        } else { // At this point, both inverse and index are externalized.
-            var inverse = externalizedInverseProcessor.getInverseSingleton(planningValue);
-            if (inverse == null) {
-                throw new IllegalArgumentException("The element (%s) is not assigned (%s)."
-                        .formatted(planningValue, sourceVariableDescriptor));
-            }
-            return ElementLocation.of(inverse, externalizedIndexProcessor.getIndex(planningValue) + 1);
-        }
-    }
-
     public Integer getIndex(Object planningValue) {
         if (externalizedIndexProcessor == null) {
             var elementLocation = elementLocationMap.get(planningValue);

core/src/main/java/ai/timefold/solver/core/impl/domain/variable/ListVariableStateSupply.java

@@ -11,7 +11,6 @@
 import ai.timefold.solver.core.impl.domain.variable.nextprev.NextElementShadowVariableDescriptor;
 import ai.timefold.solver.core.impl.domain.variable.nextprev.PreviousElementShadowVariableDescriptor;
 import ai.timefold.solver.core.preview.api.domain.metamodel.ElementLocation;
-import ai.timefold.solver.core.preview.api.domain.metamodel.LocationInList;
 
 /**
  * Single source of truth for all information about elements inside {@link PlanningListVariable list variables}.
@@ -67,18 +66,6 @@ public interface ListVariableStateSupply<Solution_> extends
      */
     ElementLocation getLocationInList(Object value);
 
-    /**
-     * Serves as a short-hand for {@link #getLocationInList(Object)} + 1.
-     * This way, we can only allocate the location instance for the next element,
-     * whereas {@link #getLocationInList(Object)} would allocate the location instance for the current element as well.
-     * This is a micro-optimization, but this code lives on the hot path.
-     *
-     * @param value never null
-     * @return never null
-     * @throws IllegalArgumentException if the value is not in the list
-     */
-    LocationInList getNextLocationInList(Object value);
-
     /**
      * Consider calling this before {@link #isAssigned(Object)} to eliminate some map accesses.
      * If unassigned count is 0, {@link #isAssigned(Object)} is guaranteed to return true.

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/list/ElementDestinationSelector.java

@@ -129,7 +129,8 @@ public Iterator<ElementLocation> iterator() {
             // Simplify tests.
             stream = Stream.concat(stream,
                     StreamSupport.stream(valueSelector.spliterator(), false)
-                            .map(v -> listVariableStateSupply.getNextLocationInList(v)));
+                            .map(v -> listVariableStateSupply.getLocationInList(v).ensureAssigned())
+                            .map(locationInList -> ElementLocation.of(locationInList.entity(), locationInList.index() + 1)));
             // If the list variable allows unassigned values, add the option of unassigning.
             if (listVariableDescriptor.allowsUnassignedValues()) {
                 stream = Stream.concat(stream, Stream.of(ElementLocation.unassigned()));

core/src/main/java/ai/timefold/solver/core/impl/heuristic/selector/list/ElementLocationRandomIterator.java

@@ -84,8 +84,10 @@ public ElementLocation next() {
                     var randomIndex = workingRandom.nextInt(unpinnedSize + 1);
                     return ElementLocation.of(entity, listVariableDescriptor.getFirstUnpinnedIndex(entity) + randomIndex);
                 }
-            } else { // Include the destination after the final element in the list.
-                return listVariableStateSupply.getNextLocationInList(value);
+            } else { // +1 to include the destination after the final element in the list.
+                var elementLocation = listVariableStateSupply.getLocationInList(value)
+                        .ensureAssigned();
+                return ElementLocation.of(elementLocation.entity(), elementLocation.index() + 1);
             }
         }
     }