@Override
    public Object parse(SourceData sourceData, int rowIndex, Context context) {
        Object valueObj = valueParser.parse(sourceData, rowIndex, context);
        if (valueObj instanceof ArrayList) {
            ArrayList<?> array = (ArrayList<?>) valueObj;
            if (array.isEmpty()) {
                return null;
            } else if (array.size() == 1) {
                return array.get(0);
            } else {
                log.warn("Array contains more than one element", new IllegalArgumentException());
                return null;
            }
        }
        return null;
    }
ElementFunction  ->  ELEMENT(array)
description:
- Return NULL if 'array' is empty or NULL;
- Return the sole element of 'array' (whose cardinality should be one).
Note: Throws an exception if array has more than one element.
inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/collection/ElementFunction.java