CODEWITHSUNDEEP
scalajdbcplayframeworkplayframework-2.0
ps0604
ps0604

Reputation: 1071

Play, Scala, JDBC and concurrency

I have a Scala class that accesses a database through JDBC:

class DataAccess {

  def select = {

    val driver = "com.mysql.jdbc.Driver"
    val url = "jdbc:mysql://localhost:3306/db"
    val username = "root"
    val password = "xxxx"

    var connection:Connection = null

    try {
      // make the connection
      Class.forName(driver)
      connection = DriverManager.getConnection(url, username, password)

      // create the statement, and run the select query
      val statement = connection.createStatement()
      val resultSet = statement.executeQuery("SELECT name, descrip FROM table1")
      while ( resultSet.next() ) {
        val name = resultSet.getString(1)
        val descrip = resultSet.getString(2)
        println("name, descrip = " + name + ", " + descrip)
      }
    } catch {
      case e => e.printStackTrace
    }
    connection.close()
  }

}

I access this class in my Play application, like so:

  def testSql = Action { 
       val da = new DataAccess
       da.select()
       Ok("success")
  }

The method testSql may be invoked by several users. Question is: could there be a race condition in the while ( resultSet.next() ) loop (or in any other part of the class)?

Note: I need to use JDBC as the SQL statement will be dynamic.

Upvotes: 0

Views: 137

Answers (1)

Jean Logeart
Jean Logeart

Reputation: 53819

No there cannot.

Each thread is working with a distinct local instance of ResultSet so there cannot be concurrent access to the same object.

Upvotes: 2

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