Treating an SQL ResultSet like a Scala Stream

Question

When I query a database and receive a (forward-only, read-only) ResultSet back, the ResultSet acts like a list of database rows.

I am trying to find some way to trea

Answer 1

Here is an alternative, similar to Sergey Alaev's and thoredge's solutions, for when we need a solution which honors the Iterator contract where hasNext is side-effect free.

Assuming a function f: ResultSet => T:

Iterator.unfold(resultSet.next()) { hasNext =>
  Option.when(hasNext)(f(resultSet), resultSet.next())
}

I've found it useful to have as map "extension method" on ResultSet.

implicit class ResultSetOps(resultSet: ResultSet) {
    def map[T](f: ResultSet => T): Iterator[T] = {
      Iterator.unfold(resultSet.next()) { hasNext =>
        Option.when(hasNext)(f(resultSet), resultSet.next())
      }
    }
  }