private void setAndValidateOrderSpec()

in flink-connector-hive/src/main/java/org/apache/flink/table/planner/delegation/hive/copy/HiveParserWindowingSpec.java [90:131]
39 lines of code
17 McCabe index (conditional complexity)

    private void setAndValidateOrderSpec(WindowFunctionSpec wFn) throws SemanticException {
        WindowSpec wdwSpec = wFn.getWindowSpec();
        wdwSpec.ensureOrderSpec(wFn);
        WindowFrameSpec wFrame = wdwSpec.getWindowFrame();
        OrderSpec order = wdwSpec.getOrder();

        BoundarySpec start = wFrame.getStart();
        BoundarySpec end = wFrame.getEnd();

        if (wFrame.getWindowType() == WindowType.RANGE) {
            if (order == null || order.getExpressions().size() == 0) {
                throw new SemanticException(
                        "Range based Window Frame needs to specify ORDER BY clause");
            }

            boolean currentRange =
                    start.getDirection() == Direction.CURRENT
                            && end.getDirection() == Direction.CURRENT;
            boolean defaultPreceding =
                    start.getDirection() == Direction.PRECEDING
                            && start.getAmt() == BoundarySpec.UNBOUNDED_AMOUNT
                            && end.getDirection() == Direction.CURRENT;
            boolean defaultFollowing =
                    start.getDirection() == Direction.CURRENT
                            && end.getDirection() == Direction.FOLLOWING
                            && end.getAmt() == BoundarySpec.UNBOUNDED_AMOUNT;
            boolean defaultPrecedingFollowing =
                    start.getDirection() == Direction.PRECEDING
                            && start.getAmt() == BoundarySpec.UNBOUNDED_AMOUNT
                            && end.getDirection() == Direction.FOLLOWING
                            && end.getAmt() == BoundarySpec.UNBOUNDED_AMOUNT;
            boolean multiOrderAllowed =
                    currentRange
                            || defaultPreceding
                            || defaultFollowing
                            || defaultPrecedingFollowing;
            if (order.getExpressions().size() != 1 && !multiOrderAllowed) {
                throw new SemanticException(
                        "Range value based Window Frame can have only 1 Sort Key");
            }
        }
    }