@Override
    public void notifyMerge(RelationalPath<?> entity, QueryMetadata md, List<Path<?>> keys,
                            List<Path<?>> columns, List<Expression<?>> values, SubQueryExpression<?> subQuery) {
        if (parent != null) {
            parent.notifyMerge(entity, md, keys, columns, values, subQuery);
        }
        for (SQLListener listener : listeners) {
            listener.notifyMerge(entity, md, keys, columns, values, subQuery);
        }
    }
{@code SQLListeners} is a {@link SQLListener} implementation which dispatches the
notifications to a list of SQLListener instances

@author tiwe
querydsl-sql/src/main/java/com/querydsl/sql/SQLListeners.java