address review comments

h2/src/main/org/h2/command/dml/Select.java

@@ -115,7 +115,8 @@ public class Select extends Query {
     private int[] groupByCopies;
 
     /**
-     * Whether this query contains aggregate functions.
+     * This flag is set when SELECT statement contains (non-window) aggregate
+     * functions, GROUP BY clause or HAVING clause.
      */
     boolean isGroupQuery;
     private boolean isGroupSortedQuery;
@@ -176,7 +177,8 @@ public class Select extends Query {
     }
 
     /**
-     * Called if this query contains aggregate functions.
+     * Set when SELECT statement contains (non-window) aggregate functions,
+     * GROUP BY clause or HAVING clause.
      */
     public void setGroupQuery() {
         isGroupQuery = true;
@@ -484,7 +486,7 @@ public class Select extends Query {
     /**
      * Update any aggregate expressions with the query stage.
      * @param columnCount number of columns
-     * @param stage stage of query (window or normal)
+     * @param stage see STAGE_RESET/STAGE_GROUP/STAGE_WINDOW in DataAnalysisOperation
      */
     void updateAgg(int columnCount, int stage) {
         for (int i = 0; i < columnCount; i++) {

h2/src/main/org/h2/expression/aggregate/AbstractAggregate.java

@@ -31,7 +31,7 @@ public abstract class AbstractAggregate extends DataAnalysisOperation {
     protected final boolean distinct;
 
     /**
-     * FILTER condition for aggregate/window
+     * FILTER condition for aggregate
      */
     protected Expression filterCondition;
 

h2/src/main/org/h2/expression/analysis/DataAnalysisOperation.java

@@ -50,7 +50,7 @@ public abstract class DataAnalysisOperation extends Expression {
     protected final Select select;
 
     /**
-     * Window clause / OVER
+     * OVER clause
      */
     protected Window over;
 
@@ -426,7 +426,7 @@ public abstract class DataAnalysisOperation extends Expression {
             ArrayList<Value[]> ordered, int rowIdColumn);
 
     /**
-     * Used to create SQL for the OVER part of the command.
+     * Used to create SQL for the OVER and FILTER clauses.
      * 
      * @param builder string builder
      * @return the builder object

h2/src/main/org/h2/mvstore/tx/TransactionStore.java

@@ -729,7 +729,7 @@ public class TransactionStore {
                         VersionedValue existingValue, VersionedValue restoredValue);
     }
 
-    private static RollbackListener ROLLBACK_LISTENER_NONE = new RollbackListener() {
+    private static final RollbackListener ROLLBACK_LISTENER_NONE = new RollbackListener() {
         @Override
         public void onRollback(MVMap<Object, VersionedValue> map, Object key,
                                 VersionedValue existingValue, VersionedValue restoredValue) {