/** * For an expression (left side or right side), finds the values * (grouped by attribute option combo). * * @param expression left or right side expression. * @param slidingWindow whether to use sliding window. * @return the values grouped by attribute option combo. */ private Map<String, Double> getValuesForExpression( Expression expression, boolean slidingWindow ) { if ( expression == null ) { return new HashMap<>(); } else if ( slidingWindow ) { return getExpressionValueMap( expression, slidingWindowEventMap ); } else { return getExpressionValueMap( expression, dataMap ); } }