Experiment: bulk clear for ifExists

Author: triceo

core/src/main/java/ai/timefold/solver/core/impl/bavet/common/AbstractIfExistsNode.java

@@ -113,8 +113,8 @@ protected void decrementCounterRight(ExistsCounter<LeftTuple_> counter) {
 
     IndexedSet<ExistsCounterHandle<LeftTuple_>> updateRightHandleSet(UniTuple<Right_> rightTuple) {
         IndexedSet<ExistsCounterHandle<LeftTuple_>> rightHandleSet = rightTuple.getStore(inputStoreIndexRightHandleSet);
-        rightHandleSet.forEach(handle -> {
-            handle.remove();
+        rightHandleSet.clear(handle -> {
+            handle.removeByRight();
             decrementCounterRight(handle.counter);
         });
         return rightHandleSet;

core/src/main/java/ai/timefold/solver/core/impl/bavet/common/AbstractIndexedJoinNode.java

@@ -82,8 +82,8 @@ public final void updateLeft(LeftTuple_ leftTuple) {
             // Prefer an update over retract-insert if possible
             innerUpdateLeft(leftTuple, consumer -> indexerRight.forEach(oldIndexKeys, consumer));
         } else {
-            IndexedSet<OutTuple_> outTupleSetLeft = leftTuple.getStore(inputStoreIndexLeftOutTupleSet);
             indexerLeft.remove(oldIndexKeys, leftTuple);
+            IndexedSet<OutTuple_> outTupleSetLeft = leftTuple.getStore(inputStoreIndexLeftOutTupleSet);
             outTupleSetLeft.forEach(this::retractOutTuple);
             // outTupleSetLeft is now empty, no need for leftTuple.setStore(...);
             indexAndPropagateLeft(leftTuple, newIndexKeys);

core/src/main/java/ai/timefold/solver/core/impl/bavet/common/ExistsCounter.java

@@ -21,7 +21,7 @@ public final class ExistsCounter<Tuple_ extends AbstractTuple>
     }
 
     public void clearWithoutCount() {
-        leftHandleSet.forEach(ExistsCounterHandle::remove);
+        leftHandleSet.clear(ExistsCounterHandle::removeByLeft);
     }
 
     public void clearIncludingCount() {

core/src/main/java/ai/timefold/solver/core/impl/bavet/common/ExistsCounterHandle.java

@@ -28,9 +28,12 @@ final class ExistsCounterHandle<LeftTuple_ extends AbstractTuple> {
         rightHandleSet.add(this);
     }
 
-    public void remove() {
-        counter.leftHandleSet.remove(this);
+    public void removeByLeft() {
         rightHandleSet.remove(this);
     }
 
+    public void removeByRight() {
+        counter.leftHandleSet.remove(this);
+    }
+
 }

core/src/main/java/ai/timefold/solver/core/impl/bavet/common/index/IndexedSet.java

@@ -104,14 +104,20 @@ public void remove(T element) {
 
     private boolean clearIfPossible() {
         if (gapCount > 0 && lastElementPosition + 1 == gapCount) { // All positions are gaps. Clear the list entirely.
-            elementList.clear();
-            gapCount = 0;
-            lastElementPosition = -1;
+            forceClear();
             return true;
         }
         return false;
     }
 
+    private void forceClear() {
+        if (elementList != null) {
+            elementList.clear();
+        }
+        gapCount = 0;
+        lastElementPosition = -1;
+    }
+
     public boolean isEmpty() {
         return size() == 0;
     }
@@ -300,4 +306,30 @@ private void forceCompaction() {
         }
     }
 
+    public void clear(Consumer<T> elementConsumer) {
+        var nonGapCount = size();
+        if (nonGapCount == 0) {
+            forceClear();
+            return;
+        }
+        var oldLastElementPosition = lastElementPosition;
+        for (var i = 0; i <= oldLastElementPosition; i++) {
+            var element = elementList.get(i);
+            if (element == null) {
+                continue;
+            }
+            elementConsumer.accept(element);
+            if (lastElementPosition != oldLastElementPosition) {
+                throw new IllegalStateException("Impossible state: the IndexedSet was modified while being cleared.");
+            }
+            elementPositionTracker.clearPosition(element);
+            // We can stop early once all non-gap elements have been processed.
+            nonGapCount--;
+            if (nonGapCount == 0) {
+                break;
+            }
+        }
+        forceClear();
+    }
+
 }