referencing columns

[Lukas Eder]

 2018-05-04 17:39 GMT+02:00 Douglas Surber <douglas.surber at oracle.com>:

> Your alternative does not include the motion methods directly. In order to
> get to next the app would have to call iterator. Having gotten an iterator
> so it can call next it cannot get back to Row.
>

Added a row() method, which would be useful regardless of the final design.
Akin to JDBC's ResultSet.getStatement() and Statement.getConnection()

  public interface Column {
    public <T> T get(Class<T> type);
    public SqlType sqlType();
    public <T> Class<T> javaType();
    public String id();
    public int index();
    public Row row();
  }


> No doubt you can write some odd things, but with a little care in the spec
> I think it would all be well and simply defined.
>

Sure, this can be specified. But I don't really see the value of the type
yet, compared to possible alternatives. E.g. slice (probably not such a
frequent use-case) could be achieved by adding columnStream() method:

  public interface Row extends Iterable<Column>{
    public long rowNumber();
    public Row cancel();
    public Column at(String id);
    public Column at(int index);
    public Stream<Column> columnStream(); // Added this method
    // forEach, iterator, spliterator
  }

Now you could call

  row.columnStream().skip(3).limit(5).forEach(c -> { ... });

"Luckily", the skip() method looks as if it were 1-based, too :)

Of course, I wish Iterable itself had a stream() method, so we would get
this for "free", but that decision has been postponed since Java 8 for a
couple of times - I forgot why. Something related to generic specialisation
/ Valhalla.

Lukas