Packages

  • package root

    This is the documentation for the Scala standard library.

    This is the documentation for the Scala standard library.

    Package structure

    The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports.

    Notable packages include:

    Other packages exist. See the complete list on the right.

    Additional parts of the standard library are shipped as separate libraries. These include:

    • scala.reflect - Scala's reflection API (scala-reflect.jar)
    • scala.xml - XML parsing, manipulation, and serialization (scala-xml.jar)
    • scala.swing - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)
    • scala.util.parsing - Parser combinators, including an example implementation of a JSON parser (scala-parser-combinators.jar)

    Automatic imports

    Identifiers in the scala package and the scala.Predef object are always in scope by default.

    Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, List is an alias for scala.collection.immutable.List.

    Other aliases refer to classes provided by the underlying platform. For example, on the JVM, String is an alias for java.lang.String.

    Definition Classes
    root
  • package scala

    Core Scala types.

    Core Scala types. They are always available without an explicit import.

    Definition Classes
    root
  • package concurrent

    This package object contains primitives for concurrent and parallel programming.

    This package object contains primitives for concurrent and parallel programming.

    Guide

    A more detailed guide to Futures and Promises, including discussion and examples can be found at http://docs.scala-lang.org/overviews/core/futures.html.

    Common Imports

    When working with Futures, you will often find that importing the whole concurrent package is convenient, furthermore you are likely to need an implicit ExecutionContext in scope for many operations involving Futures and Promises:

    import scala.concurrent._
import ExecutionContext.Implicits.global

    Specifying Durations

    Operations often require a duration to be specified. A duration DSL is available to make defining these easier:

    import scala.concurrent.duration._
val d: Duration = 10.seconds

    Using Futures For Non-blocking Computation

    Basic use of futures is easy with the factory method on Future, which executes a provided function asynchronously, handing you back a future result of that function without blocking the current thread. In order to create the Future you will need either an implicit or explicit ExecutionContext to be provided:

    import scala.concurrent._
import ExecutionContext.Implicits.global  // implicit execution context

val firstZebra: Future[Int] = Future {
  val source = scala.io.Source.fromFile("/etc/dictionaries-common/words")
  source.toSeq.indexOfSlice("zebra")
}

    Avoid Blocking

    Although blocking is possible in order to await results (with a mandatory timeout duration):

    import scala.concurrent.duration._
Await.result(firstZebra, 10.seconds)

    and although this is sometimes necessary to do, in particular for testing purposes, blocking in general is discouraged when working with Futures and concurrency in order to avoid potential deadlocks and improve performance. Instead, use callbacks or combinators to remain in the future domain:

    val animalRange: Future[Int] = for {
  aardvark <- firstAardvark
  zebra <- firstZebra
} yield zebra - aardvark

animalRange.onSuccess {
  case x if x > 500000 => println("It's a long way from Aardvark to Zebra")
}
    Definition Classes
    scala
  • package duration
    Definition Classes
    concurrent
  • Deadline
  • DoubleMult
  • Duration
  • DurationConversions
  • DurationDouble
  • DurationInt
  • DurationLong
  • FiniteDuration
  • IntMult
  • LongMult
  • fromNow
  • span
c

scala.concurrent.duration

DurationDouble

implicit final class DurationDouble extends AnyVal with DurationConversions

Source
package.scala
Linear Supertypes
DurationConversions, AnyVal, Any
Type Hierarchy
Ordering
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  2. By Inheritance
Inherited
  1. DurationDouble
  2. DurationConversions
  3. AnyVal
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new DurationDouble(d: Double)

Value Members

  1. def day[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  2. def day: FiniteDuration
    Definition Classes
    DurationConversions
  3. def days[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  4. def days: FiniteDuration
    Definition Classes
    DurationConversions
  5. def getClass(): Class[_ <: AnyVal]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

    a class object corresponding to the runtime type of the receiver.

    Definition Classes
    AnyVal → Any
  6. def hour[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  7. def hour: FiniteDuration
    Definition Classes
    DurationConversions
  8. def hours[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  9. def hours: FiniteDuration
    Definition Classes
    DurationConversions
  10. def micro[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  11. def micro: FiniteDuration
    Definition Classes
    DurationConversions
  12. def micros[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  13. def micros: FiniteDuration
    Definition Classes
    DurationConversions
  14. def microsecond[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  15. def microsecond: FiniteDuration
    Definition Classes
    DurationConversions
  16. def microseconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  17. def microseconds: FiniteDuration
    Definition Classes
    DurationConversions
  18. def milli[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  19. def milli: FiniteDuration
    Definition Classes
    DurationConversions
  20. def millis[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  21. def millis: FiniteDuration
    Definition Classes
    DurationConversions
  22. def millisecond[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  23. def millisecond: FiniteDuration
    Definition Classes
    DurationConversions
  24. def milliseconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  25. def milliseconds: FiniteDuration
    Definition Classes
    DurationConversions
  26. def minute[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  27. def minute: FiniteDuration
    Definition Classes
    DurationConversions
  28. def minutes[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  29. def minutes: FiniteDuration
    Definition Classes
    DurationConversions
  30. def nano[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  31. def nano: FiniteDuration
    Definition Classes
    DurationConversions
  32. def nanos[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  33. def nanos: FiniteDuration
    Definition Classes
    DurationConversions
  34. def nanosecond[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  35. def nanosecond: FiniteDuration
    Definition Classes
    DurationConversions
  36. def nanoseconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  37. def nanoseconds: FiniteDuration
    Definition Classes
    DurationConversions
  38. def second[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  39. def second: FiniteDuration
    Definition Classes
    DurationConversions
  40. def seconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  41. def seconds: FiniteDuration
    Definition Classes
    DurationConversions