@Override
    public Object parse(SourceData sourceData, int rowIndex, Context context) {
        int num = 0;
        for (ValueParser valueParser : nodeList) {
            if (valueParser == null) {
                num++;
                continue;
            }
            Object value = valueParser.parse(sourceData, rowIndex, context);
            if (value == null) {
                num++;
            }
        }
        return num;
    }
NumNullsFunction  ->  num_nulls(expr1,expr2,...)
description:
- Return the number of null arguments.
inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/arithmetic/NumNullsFunction.java