Play Framework/Scala example source code file (ClosableLazySpec.scala)

This example Play Framework source code file (ClosableLazySpec.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Play Framework (and Scala) source code examples by using tags.

All credit for the original source code belongs to Play Framework; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Play Framework tags/keywords

atomicinteger, closablelazy, closablelazyspec, concurrent, core, duration, future, minutes, play, play framework, promise, specification, time

The ClosableLazySpec.scala Play Framework example source code

/*
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */
package play.core

import java.util.concurrent.atomic.AtomicInteger
import org.specs2.mutable.Specification
import scala.concurrent.{ Await, Future, Promise }
import scala.concurrent.duration._

object ClosableLazySpec extends Specification {

  "ClosableLazy" should {

    "create a value when first accessed" in {
      val createCount = new AtomicInteger()
      val cl = new ClosableLazy[String] {
        protected def create() = {
          createCount.incrementAndGet()
          ("hello", () => ())
        }
      }
      createCount.get must_== 0
      cl.get must_== "hello"
      createCount.get must_== 1
      cl.get must_== "hello"
      createCount.get must_== 1
      cl.close()
      createCount.get must_== 1
    }

    "call the close function when first closed" in {
      val closeCount = new AtomicInteger()

      val cl = new ClosableLazy[String] {
        protected def create() = {
          ("hat", () => closeCount.incrementAndGet())
        }
      }
      closeCount.get must_== 0
      cl.get must_== "hat"
      closeCount.get must_== 0
      cl.get must_== "hat"
      closeCount.get must_== 0
      cl.close()
      closeCount.get must_== 1
      cl.close()
      closeCount.get must_== 1

    }

    "be closable before the first call to get" in {
      val closeCount = new AtomicInteger()

      val cl = new ClosableLazy[String] {
        protected def create() = {
          ("sock", () => closeCount.incrementAndGet())
        }
      }
      closeCount.get must_== 0
      cl.close()
      closeCount.get must_== 0
      cl.get must throwAn[IllegalStateException]
      closeCount.get must_== 0
      cl.close()
      closeCount.get must_== 0

    }

    "throw an exception when accessed after being closed" in {
      val cl = new ClosableLazy[String] {
        protected def create() = ("oof", () => ())
      }
      cl.get must_== "oof"
      cl.close()
      cl.get must throwAn[IllegalStateException]
    }

    "not deadlock when get is called during the close function" in {

      val getResultPromise = Promise[String]
      val test = Future {
        lazy val cl: ClosableLazy[String] = new ClosableLazy[String] {
          protected def create() = {
            ("banana", { () =>
              val getResult = Future[String] {
                cl.get()
              }
              getResultPromise.completeWith(getResult)
              Await.result(getResult, Duration(2, MINUTES))
            })
          }
        }
        cl.get must_== "banana"
        cl.close() must_== (())
      }

      // Our get result should happen immediately and throw an IllegalStateException
      // because the ClosableLazy is closed. Use a long duration so this will work
      // on slow machines.
      Await.result(getResultPromise.future, Duration(1, MINUTES)) must throwAn[IllegalStateException]
    }

  }

}