I have a question, which one of these 2 code block...

# coroutines

[Hong Phuc]

I have a question, which one of these 2 code blocks is better in term of closing resources and coroutine structure? Thanks in advance

override suspend fun getId(email: String): String? = withContext(Dispatchers.IO) {
        dataSource.connection.use { connection ->
            connection.prepareStatement("SELECT id FROM users WHERE email = ?;").use { statement ->
                statement.setString(1, email)
                statement.executeQuery().use { resultSet ->
                    if (resultSet.next()) {
                        resultSet.getString("id")
                    } else {
                        null
                    }
                }
            }
        }
    }

override suspend fun getId(email: String): String? {

    var userId: String? = null

    withContext(Dispatchers.IO) {

        val dbconnection = dataSource.connection

        val statement: PreparedStatement = dbconnection.prepareStatement("SELECT * FROM users WHERE email = ?;")

        statement.setString(1, email)

        val resultSet: ResultSet = statement.executeQuery()



        while(resultSet.next()) {
            userId =  resultSet.getString("id")

            statement.close()
            dbconnection.close()

            return@withContext userId
        }



    }

[Joffrey]

The second snippet doesn't use a `try`/`finally` block to close the resources, so they won't be closed if an exception is thrown. The approach with use is more correct (at least at a quick glance, I didn't dissect the code).

[Joffrey]

Also, why declare userId so far from its usage in the second snippet?

[Hong Phuc]

I couldn’t remember why userId was there actually

[Hong Phuc]

Does using use affect the testability of the code, since one statement flow into another, I wouldn’t be able to test them separately?

[Joffrey]

Not sure what you mean here. You only have one function, so from the outside use will look the same as with finally

[Hong Phuc]

I see. Thanks Joffrey