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 (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:

    import scala.concurrent._

    When using things like Futures, it is often required to have an implicit ExecutionContext in scope. The general advice for these implicits are as follows.

    If the code in question is a class or method definition, and no ExecutionContext is available, request one from the caller by adding an implicit parameter list:

    def myMethod(myParam: MyType)(implicit ec: ExecutionContext) = …
//Or
class MyClass(myParam: MyType)(implicit ec: ExecutionContext) { … }

    This allows the caller of the method, or creator of the instance of the class, to decide which ExecutionContext should be used.

    For typical REPL usage and experimentation, importing the global ExecutionContext is often desired.

    import scala.concurrent.ExcutionContext.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
Ordering
  1. Alphabetic
  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
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. All

Instance Constructors

  1. new DurationDouble(d: Double)

Value Members

  1. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    Any
  2. final def ##(): Int

    Equivalent to x.hashCode except for boxed numeric types and null.

    Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

    returns

    a hash value consistent with ==

    Definition Classes
    Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from DurationDouble to any2stringadd[DurationDouble] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (DurationDouble, B)
    Implicit
    This member is added by an implicit conversion from DurationDouble to ArrowAssoc[DurationDouble] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean

    Test two objects for equality.

    Test two objects for equality. The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    Any
  6. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown

    ClassCastException if the receiver object is not an instance of the erasure of type T0.

  7. def day[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  8. def day: FiniteDuration
    Definition Classes
    DurationConversions
  9. def days[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  10. def days: FiniteDuration
    Definition Classes
    DurationConversions
  11. def durationIn(unit: TimeUnit): FiniteDuration
    Attributes
    protected
    Definition Classes
    DurationDouble → DurationConversions
  12. def ensuring(cond: (DurationDouble) ⇒ Boolean, msg: ⇒ Any): DurationDouble
    Implicit
    This member is added by an implicit conversion from DurationDouble to Ensuring[DurationDouble] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: (DurationDouble) ⇒ Boolean): DurationDouble
    Implicit
    This member is added by an implicit conversion from DurationDouble to Ensuring[DurationDouble] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. def ensuring(cond: Boolean, msg: ⇒ Any): DurationDouble
    Implicit
    This member is added by an implicit conversion from DurationDouble to Ensuring[DurationDouble] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. def ensuring(cond: Boolean): DurationDouble
    Implicit
    This member is added by an implicit conversion from DurationDouble to Ensuring[DurationDouble] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  16. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

    Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

    Implicit
    This member is added by an implicit conversion from DurationDouble to StringFormat[DurationDouble] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  17. 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
  18. def hour[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  19. def hour: FiniteDuration
    Definition Classes
    DurationConversions
  20. def hours[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  21. def hours: FiniteDuration
    Definition Classes
    DurationConversions
  22. final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is T0.

    Test whether the dynamic type of the receiver object is T0.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    Definition Classes
    Any
  23. def micro[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  24. def micro: FiniteDuration
    Definition Classes
    DurationConversions
  25. def micros[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  26. def micros: FiniteDuration
    Definition Classes
    DurationConversions
  27. def microsecond[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  28. def microsecond: FiniteDuration
    Definition Classes
    DurationConversions
  29. def microseconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  30. def microseconds: FiniteDuration
    Definition Classes
    DurationConversions
  31. def milli[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  32. def milli: FiniteDuration
    Definition Classes
    DurationConversions
  33. def millis[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  34. def millis: FiniteDuration
    Definition Classes
    DurationConversions
  35. def millisecond[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  36. def millisecond: FiniteDuration
    Definition Classes
    DurationConversions
  37. def milliseconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  38. def milliseconds: FiniteDuration
    Definition Classes
    DurationConversions
  39. def minute[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  40. def minute: FiniteDuration
    Definition Classes
    DurationConversions
  41. def minutes[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  42. def minutes: FiniteDuration
    Definition Classes
    DurationConversions
  43. def nano[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  44. def nano: FiniteDuration
    Definition Classes
    DurationConversions
  45. def nanos[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  46. def nanos: FiniteDuration
    Definition Classes
    DurationConversions
  47. def nanosecond[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  48. def nanosecond: FiniteDuration
    Definition Classes
    DurationConversions
  49. def nanoseconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  50. def nanoseconds: FiniteDuration
    Definition Classes
    DurationConversions
  51. def second[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  52. def second: FiniteDuration
    Definition Classes
    DurationConversions
  53. def seconds[C](c: C)(implicit ev: Classifier[C]): R
    Definition Classes
    DurationConversions
  54. def seconds: FiniteDuration
    Definition Classes
    DurationConversions
  55. def toString(): String

    Returns a string representation of the object.

    Returns a string representation of the object.

    The default representation is platform dependent.

    returns

    a string representation of the object.

    Definition Classes
    Any
  56. def →[B](y: B): (DurationDouble, B)
    Implicit
    This member is added by an implicit conversion from DurationDouble to ArrowAssoc[DurationDouble] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Inherited from DurationConversions

Inherited from AnyVal

Inherited from Any

Inherited by implicit conversion any2stringadd from DurationDouble to any2stringadd[DurationDouble]

Inherited by implicit conversion StringFormat from DurationDouble to StringFormat[DurationDouble]

Inherited by implicit conversion Ensuring from DurationDouble to Ensuring[DurationDouble]

Inherited by implicit conversion ArrowAssoc from DurationDouble to ArrowAssoc[DurationDouble]

Ungrouped