I have a class which parses CSV file. This CSV file doesn't have header. Also it mus contain only 1 column.

I want to add validation for columns count.

My current code is:

    CsvSchema csvSchema = CsvSchema.builder().addColumn("MY_COLUMN").build();
    try (MappingIterator<Map<String, String>> iter = csvMapper.readerFor(Map.class)
            .with(schema)
            .readValues(new InputStreamReader(inputStream))) {
            ....
           while (iter.hasNextValue()) {
               Map<String, String> map = iter.next();
               ...
           }

    }

At this case map contains only 1 key/pair so it sees only first column. If there are 2, 3 or more columns - all of them are ignored. So this code doesn't allow me to understand amount of columns.

I tried to use another schema:

CsvSchema csvSchema = CsvSchema.emptySchema()
                .withUseHeader(false)
                .withComments()
                .withColumnSeparator(columnSeparator);

But it lead to the parsing error:

Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.Object,java.lang.Object>` from Array value (token `JsonToken.START_ARRAY`)
 at [Source: (InputStreamReader); line: UNKNOWN, column: UNKNOWN]

Could you please give me a hint how to achieve my aim ?