chore: minor improvements

Author: zepfred

core/src/main/java/ai/timefold/solver/core/impl/domain/valuerange/ValueRangeCache.java

@@ -82,8 +82,7 @@ public Iterator<Value_> iterator(Random workingRandom) {
      * @param sorter never null, the sorter
      */
     public ValueRangeCache<Value_> sort(ValueRangeSorter<Value_> sorter) {
-        var valuesWithFastRandomAccessSorted = new ArrayList<>(valuesWithFastRandomAccess);
-        sorter.sort(valuesWithFastRandomAccessSorted);
+        var valuesWithFastRandomAccessSorted = sorter.sort(valuesWithFastRandomAccess);
         return switch (cacheType) {
             case USER_VALUES -> Builder.FOR_USER_VALUES.buildCache(valuesWithFastRandomAccessSorted);
             case TRUSTED_VALUES -> Builder.FOR_TRUSTED_VALUES.buildCache(valuesWithFastRandomAccessSorted);

core/src/main/java/ai/timefold/solver/core/impl/domain/valuerange/buildin/collection/ListValueRange.java

@@ -1,6 +1,5 @@
 package ai.timefold.solver.core.impl.domain.valuerange.buildin.collection;
 
-import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Random;
@@ -60,9 +59,8 @@ public boolean contains(@Nullable T value) {
 
     @Override
     public ValueRange<T> sort(ValueRangeSorter<T> sorter) {
-        var newList = new ArrayList<>(list);
-        sorter.sort(newList);
-        return new ListValueRange<>(newList, isValueImmutable);
+        var sortedList = sorter.sort(list);
+        return new ListValueRange<>(sortedList, isValueImmutable);
     }
 
     @Override

core/src/main/java/ai/timefold/solver/core/impl/domain/valuerange/buildin/composite/CompositeCountableValueRange.java

@@ -41,8 +41,8 @@ public CompositeCountableValueRange(List<? extends AbstractCountableValueRange<T
     }
 
     private CompositeCountableValueRange(ValueRangeCache<T> cache, boolean isValueImmutable) {
-        this.isValueImmutable = isValueImmutable;
         this.cache = cache;
+        this.isValueImmutable = isValueImmutable;
     }
 
     @Override

core/src/main/java/ai/timefold/solver/core/impl/domain/valuerange/sort/SelectionSorterAdapter.java

@@ -1,5 +1,7 @@
 package ai.timefold.solver.core.impl.domain.valuerange.sort;
 
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
@@ -18,8 +20,10 @@ public static <Solution_, T> ValueRangeSorter<T> of(Solution_ solution, Selectio
     }
 
     @Override
-    public void sort(List<T> selectionList) {
-        selectionSorter.sort(solution, selectionList);
+    public List<T> sort(List<T> selectionList) {
+        var newList = new ArrayList<>(selectionList);
+        selectionSorter.sort(solution, newList);
+        return Collections.unmodifiableList(newList);
     }
 
     @Override

core/src/main/java/ai/timefold/solver/core/impl/domain/valuerange/sort/ValueRangeSorter.java

@@ -15,11 +15,11 @@
 public interface ValueRangeSorter<T> {
 
     /**
-     * Apply an in-place sorting operation.
+     * Creates a copy of the provided list and sort the data.
      * 
-     * @param selectionList never null, a {@link List} of value that will be sorted.
+     * @param selectionList never null, a {@link List} of values that will be used as input for sorting.
      */
-    void sort(List<T> selectionList);
+    List<T> sort(List<T> selectionList);
 
     /**
      * Creates a copy of the provided set and sort the data.