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From "Gary Gregory (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CSV-213) CSVParser#iterator()#hasNext() fails
Date Fri, 21 Jul 2017 03:29:00 GMT

    [ https://issues.apache.org/jira/browse/CSV-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16095718#comment-16095718
] 

Gary Gregory commented on CSV-213:
----------------------------------

This is normal behavior with the current architecture: The {{iterator()}} API presents an
object that is backed by data in the {{CSVParser}} as the parser is _streaming_ over the file.
The {{CSVParser}} is like a forward-only stream.

When you create a new {{Iterator}} you are only created a new view on the same position in
the parser's stream.

For the behavior you want, you need to open a new {{CSVParser}}.

You can also abreviate the parser creation like this:

{code:java}
CSVParser parser = csvFormat.parse(new InputStreamReader(new FileInputStream(csvFile), StandardCharsets.UTF_8));
{code}

> CSVParser#iterator()#hasNext() fails
> ------------------------------------
>
>                 Key: CSV-213
>                 URL: https://issues.apache.org/jira/browse/CSV-213
>             Project: Commons CSV
>          Issue Type: Bug
>          Components: Parser
>    Affects Versions: 1.4
>         Environment: linux/osx
>            Reporter: Lukas Vasek
>            Priority: Blocker
>         Attachments: 999751170.patch.csv
>
>
> Hello,
> with class sample below and attached fail the program fails. Problem is that iterator
wrongly computes the records. If hasNext is true then next record should be fetched.
> + wouldn't it be better to provide currentRecord also?
> {code:java}
> public class Test {
>     private static final CSVFormat csvFormat =
>             CSVFormat.DEFAULT
>                     .withDelimiter(';')
>                     .withFirstRecordAsHeader()
>                     .withRecordSeparator('\n')
>                     .withQuoteMode(QuoteMode.ALL);
>     private static Optional<String[]> createEndChannel(File csvFile) {
>         try (Reader reader = new InputStreamReader(new FileInputStream(csvFile), StandardCharsets.UTF_8);
>              CSVParser parser = new CSVParser(reader, csvFormat)) {
>             if (parser.iterator().hasNext()) {
>                 System.out.println(parser.getCurrentLineNumber());
>                 System.out.println(parser.getRecordNumber());
>                 // get only first record we don't need other's
>                 CSVRecord firstRecord = parser.iterator().next(); // this fails
>                 return Optional.of(null);
>             }
>         } catch (IOException e) {
>             throw new RuntimeException("Error while adding end channel to csv", e);
>         }
>         return Optional.empty();
>     }
>     public static void main(String[] args) {
>         createEndChannel(new File("/tmp/999751170.patch.csv"));
>         //createEndChannel(new File("/tmp/129441.csv"));
>     }
> }
> {code}



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