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:

    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 https://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 words = Files.readAllLines("/etc/dictionaries-common/words").asScala
  words.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

case class Deadline extends Ordered[Deadline] with Product with Serializable

This class stores a deadline, as obtained via Deadline.now or the duration DSL:

import scala.concurrent.duration._
3.seconds.fromNow

Its main purpose is to manage repeated attempts to achieve something (like awaiting a condition) by offering the methods hasTimeLeft and timeLeft. All durations are measured according to System.nanoTime; this does not take into account changes to the system clock (such as leap seconds).

Source
Deadline.scala
Linear Supertypes
java.io.Serializable, Product, Equals, math.Ordered[Deadline], Comparable[Deadline], AnyRef, Any
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Deadline
  2. Serializable
  3. Product
  4. Equals
  5. Ordered
  6. Comparable
  7. AnyRef
  8. Any
Implicitly
  1. by orderingToOrdered
  2. by any2stringadd
  3. by StringFormat
  4. by Ensuring
  5. by ArrowAssoc
  1. Hide All
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Visibility
  1. Public
  2. Protected

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
    AnyRef → 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
    AnyRef → Any
  3. def +(other: FiniteDuration): Deadline

    Return a deadline advanced (i.e., moved into the future) by the given duration.

  4. def -(other: Deadline): FiniteDuration

    Calculate time difference between this and the other deadline, where the result is directed (i.e., may be negative).

  5. def -(other: FiniteDuration): Deadline

    Return a deadline moved backwards (i.e., towards the past) by the given duration.

  6. def ->[B](y: B): (Deadline, B)
    Implicit
    This member is added by an implicit conversion from Deadline toArrowAssoc[Deadline] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  7. def <(that: Deadline): Boolean

    Returns true if this is less than that

    Returns true if this is less than that

    Definition Classes
    Ordered
  8. def <=(that: Deadline): Boolean

    Returns true if this is less than or equal to that.

    Returns true if this is less than or equal to that.

    Definition Classes
    Ordered
  9. final def ==(arg0: Any): Boolean

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    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
    AnyRef → Any
  10. def >(that: Deadline): Boolean

    Returns true if this is greater than that.

    Returns true if this is greater than that.

    Definition Classes
    Ordered
  11. def >=(that: Deadline): Boolean

    Returns true if this is greater than or equal to that.

    Returns true if this is greater than or equal to that.

    Definition Classes
    Ordered
  12. 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.

  13. def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
    Note

    not specified by SLS as a member of AnyRef

  14. def compare(other: Deadline): Int

    The natural ordering for deadline is determined by the natural order of the underlying (finite) duration.

    The natural ordering for deadline is determined by the natural order of the underlying (finite) duration.

    Definition Classes
    Deadline → Ordered
  15. def compareTo(that: Deadline): Int

    Result of comparing this with operand that.

    Result of comparing this with operand that.

    Definition Classes
    Ordered → Comparable
  16. def ensuring(cond: (Deadline) => Boolean, msg: => Any): Deadline
    Implicit
    This member is added by an implicit conversion from Deadline toEnsuring[Deadline] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  17. def ensuring(cond: (Deadline) => Boolean): Deadline
    Implicit
    This member is added by an implicit conversion from Deadline toEnsuring[Deadline] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  18. def ensuring(cond: Boolean, msg: => Any): Deadline
    Implicit
    This member is added by an implicit conversion from Deadline toEnsuring[Deadline] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  19. def ensuring(cond: Boolean): Deadline
    Implicit
    This member is added by an implicit conversion from Deadline toEnsuring[Deadline] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  20. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (that) is a reference to the receiver object (this).

    Tests whether the argument (that) is a reference to the receiver object (this).

    The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
    • null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    returns

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

    Definition Classes
    AnyRef
  21. def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
    Note

    not specified by SLS as a member of AnyRef

  22. final def getClass(): Class[_ <: AnyRef]

    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
    AnyRef → Any
    Annotations
    @native()
  23. def hasTimeLeft(): Boolean

    Determine whether the deadline still lies in the future at the point where this method is called.

    Determine whether the deadline still lies in the future at the point where this method is called.

    Note that on some systems this operation is costly because it entails a system call. Check System.nanoTime for your platform.

  24. final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object has the same erasure as T0.

    Test whether the dynamic type of the receiver object has the same erasure as T0.

    Depending on what T0 is, the test is done in one of the below ways:

    • T0 is a non-parameterized class type, e.g. BigDecimal: this method returns true if the value of the receiver object is a BigDecimal or a subtype of BigDecimal.
    • T0 is a parameterized class type, e.g. List[Int]: this method returns true if the value of the receiver object is some List[X] for any X. For example, List(1, 2, 3).isInstanceOf[List[String]] will return true.
    • T0 is some singleton type x.type or literal x: this method returns this.eq(x). For example, x.isInstanceOf[1] is equivalent to x.eq(1)
    • T0 is an intersection X with Y or X & Y: this method is equivalent to x.isInstanceOf[X] && x.isInstanceOf[Y]
    • T0 is a union X | Y: this method is equivalent to x.isInstanceOf[X] || x.isInstanceOf[Y]
    • T0 is a type parameter or an abstract type member: this method is equivalent to isInstanceOf[U] where U is T0's upper bound, Any if T0 is unbounded. For example, x.isInstanceOf[A] where A is an unbounded type parameter will return true for any value of x.

    This is exactly equivalent to the type pattern _: T0

    returns

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

    Definition Classes
    Any
    Note

    due to the unexpectedness of List(1, 2, 3).isInstanceOf[List[String]] returning true and x.isInstanceOf[A] where A is a type parameter or abstract member returning true, these forms issue a warning.

  25. def isOverdue(): Boolean

    Determine whether the deadline lies in the past at the point where this method is called.

    Determine whether the deadline lies in the past at the point where this method is called.

    Note that on some systems this operation is costly because it entails a system call. Check System.nanoTime for your platform.

  26. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

    true if the argument is not a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  27. final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  28. final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  29. def productElementNames: Iterator[String]

    An iterator over the names of all the elements of this product.

    An iterator over the names of all the elements of this product.

    Definition Classes
    Product
  30. final def synchronized[T0](arg0: => T0): T0

    Executes the code in body with an exclusive lock on this.

    Executes the code in body with an exclusive lock on this.

    returns

    the result of body

    Definition Classes
    AnyRef
  31. val time: FiniteDuration
  32. def timeLeft: FiniteDuration

    Calculate time difference between this duration and now; the result is negative if the deadline has passed.

    Calculate time difference between this duration and now; the result is negative if the deadline has passed.

    Note that on some systems this operation is costly because it entails a system call. Check System.nanoTime for your platform.

  33. final def wait(): Unit

    See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--.

    See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--.

    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
    Note

    not specified by SLS as a member of AnyRef

  34. final def wait(arg0: Long, arg1: Int): Unit

    See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-

    See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-

    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
    Note

    not specified by SLS as a member of AnyRef

  35. final def wait(arg0: Long): Unit

    See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-.

    See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-.

    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
    Note

    not specified by SLS as a member of AnyRef

Shadowed Implicit Value Members

  1. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from Deadline toany2stringadd[Deadline] performed by method any2stringadd in scala.Predef.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: any2stringadd[Deadline]).+(other)
    Definition Classes
    any2stringadd
  2. def <(that: Deadline): Boolean

    Returns true if this is less than that

    Returns true if this is less than that

    Implicit
    This member is added by an implicit conversion from Deadline tomath.Ordered[Deadline] performed by method orderingToOrdered in scala.math.Ordered.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: math.Ordered[Deadline]).<(that)
    Definition Classes
    Ordered
  3. def <=(that: Deadline): Boolean

    Returns true if this is less than or equal to that.

    Returns true if this is less than or equal to that.

    Implicit
    This member is added by an implicit conversion from Deadline tomath.Ordered[Deadline] performed by method orderingToOrdered in scala.math.Ordered.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: math.Ordered[Deadline]).<=(that)
    Definition Classes
    Ordered
  4. def >(that: Deadline): Boolean

    Returns true if this is greater than that.

    Returns true if this is greater than that.

    Implicit
    This member is added by an implicit conversion from Deadline tomath.Ordered[Deadline] performed by method orderingToOrdered in scala.math.Ordered.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: math.Ordered[Deadline]).>(that)
    Definition Classes
    Ordered
  5. def >=(that: Deadline): Boolean

    Returns true if this is greater than or equal to that.

    Returns true if this is greater than or equal to that.

    Implicit
    This member is added by an implicit conversion from Deadline tomath.Ordered[Deadline] performed by method orderingToOrdered in scala.math.Ordered.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: math.Ordered[Deadline]).>=(that)
    Definition Classes
    Ordered
  6. def compare(that: Deadline): Int

    Result of comparing this with operand that.

    Result of comparing this with operand that.

    Implement this method to determine how instances of A will be sorted.

    Returns x where:

    • x < 0 when this < that
    • x == 0 when this == that
    • x > 0 when this > that
    Implicit
    This member is added by an implicit conversion from Deadline tomath.Ordered[Deadline] performed by method orderingToOrdered in scala.math.Ordered.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: math.Ordered[Deadline]).compare(that)
    Definition Classes
    Ordered
  7. def compareTo(that: Deadline): Int

    Result of comparing this with operand that.

    Result of comparing this with operand that.

    Implicit
    This member is added by an implicit conversion from Deadline tomath.Ordered[Deadline] performed by method orderingToOrdered in scala.math.Ordered.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (deadline: math.Ordered[Deadline]).compareTo(that)
    Definition Classes
    Ordered → Comparable

Deprecated Value Members

  1. 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 Deadline toStringFormat[Deadline] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  2. def →[B](y: B): (Deadline, B)
    Implicit
    This member is added by an implicit conversion from Deadline toArrowAssoc[Deadline] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from java.io.Serializable

Inherited from Product

Inherited from Equals

Inherited from math.Ordered[Deadline]

Inherited from Comparable[Deadline]

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion orderingToOrdered fromDeadline to math.Ordered[Deadline]

Inherited by implicit conversion any2stringadd fromDeadline to any2stringadd[Deadline]

Inherited by implicit conversion StringFormat fromDeadline to StringFormat[Deadline]

Inherited by implicit conversion Ensuring fromDeadline to Ensuring[Deadline]

Inherited by implicit conversion ArrowAssoc fromDeadline to ArrowAssoc[Deadline]

Ungrouped