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scala

Enumeration

abstract class Enumeration extends Serializable

Defines a finite set of values specific to the enumeration. Typically these values enumerate all possible forms something can take and provide a lightweight alternative to case classes.

Each call to a Value method adds a new unique value to the enumeration. To be accessible, these values are usually defined as val members of the enumeration.

All values in an enumeration share a common, unique type defined as the Value type member of the enumeration (Value selected on the stable identifier path of the enumeration instance).

Values SHOULD NOT be added to an enumeration after its construction; doing so makes the enumeration thread-unsafe. If values are added to an enumeration from multiple threads (in a non-synchronized fashion) after construction, the behavior of the enumeration is undefined.

Self Type
Enumeration
Annotations
@SerialVersionUID()
Source
Enumeration.scala
Examples:
  1. // Define a new enumeration with a type alias and work with the full set of enumerated values
    object WeekDay extends Enumeration {
      type WeekDay = Value
      val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value
    }
    import WeekDay._
    
    def isWorkingDay(d: WeekDay) = ! (d == Sat || d == Sun)
    
    WeekDay.values filter isWorkingDay foreach println
    // output:
    // Mon
    // Tue
    // Wed
    // Thu
    // Fri
  2. ,
  3. // Example of adding attributes to an enumeration by extending the Enumeration.Val class
    object Planet extends Enumeration {
      protected case class Val(mass: Double, radius: Double) extends super.Val {
        def surfaceGravity: Double = Planet.G * mass / (radius * radius)
        def surfaceWeight(otherMass: Double): Double = otherMass * surfaceGravity
      }
      import scala.language.implicitConversions
      implicit def valueToPlanetVal(x: Value): Val = x.asInstanceOf[Val]
    
      val G: Double = 6.67300E-11
      val Mercury = Val(3.303e+23, 2.4397e6)
      val Venus   = Val(4.869e+24, 6.0518e6)
      val Earth   = Val(5.976e+24, 6.37814e6)
      val Mars    = Val(6.421e+23, 3.3972e6)
      val Jupiter = Val(1.9e+27, 7.1492e7)
      val Saturn  = Val(5.688e+26, 6.0268e7)
      val Uranus  = Val(8.686e+25, 2.5559e7)
      val Neptune = Val(1.024e+26, 2.4746e7)
    }
    
    println(Planet.values.filter(_.radius > 7.0e6))
    // output:
    // Planet.ValueSet(Jupiter, Saturn, Uranus, Neptune)
Linear Supertypes
Known Subclasses
Type Hierarchy
Ordering
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  2. By Inheritance
Inherited
  1. Enumeration
  2. Serializable
  3. AnyRef
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new Enumeration()
  2. new Enumeration(initial: Int)

    initial

    The initial value from which to count the integers that identifies values at run-time.

Type Members

  1. class Val extends Value with Serializable

    A class implementing the scala.Enumeration.Value type.

    A class implementing the scala.Enumeration.Value type. This class can be overridden to change the enumeration's naming and integer identification behaviour.

    Attributes
    protected
    Annotations
    @SerialVersionUID()
  2. abstract class Value extends Ordered[Value] with Serializable

    The type of the enumerated values.

    The type of the enumerated values.

    Annotations
    @SerialVersionUID()
  3. class ValueSet extends AbstractSet[Value] with SortedSet[Value] with SortedSetOps[Value, SortedSet, ValueSet] with StrictOptimizedIterableOps[Value, Set, ValueSet] with Serializable

    A class for sets of values.

    A class for sets of values. Iterating through this set will yield values in increasing order of their ids.

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: String): String
    Implicit
    This member is added by an implicit conversion from Enumeration toany2stringadd[Enumeration] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Enumeration, B)
    Implicit
    This member is added by an implicit conversion from Enumeration toArrowAssoc[Enumeration] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. 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
  6. final def Value(i: Int, name: String): Value

    Creates a fresh value, part of this enumeration, called name and identified by the integer i.

    Creates a fresh value, part of this enumeration, called name and identified by the integer i.

    i

    An integer that identifies this value at run-time. It must be unique amongst all values of the enumeration.

    name

    A human-readable name for that value.

    returns

    Fresh value with the provided identifier i and name name.

    Attributes
    protected
  7. final def Value(name: String): Value

    Creates a fresh value, part of this enumeration, called name.

    Creates a fresh value, part of this enumeration, called name.

    name

    A human-readable name for that value.

    returns

    Fresh value called name.

    Attributes
    protected
  8. final def Value(i: Int): Value

    Creates a fresh value, part of this enumeration, identified by the integer i.

    Creates a fresh value, part of this enumeration, identified by the integer i.

    i

    An integer that identifies this value at run-time. It must be unique amongst all values of the enumeration.

    returns

    Fresh value identified by i.

    Attributes
    protected
  9. final def Value: Value

    Creates a fresh value, part of this enumeration.

    Creates a fresh value, part of this enumeration.

    Attributes
    protected
  10. final def apply(x: Int): Value

    The value of this enumeration with given id x

  11. 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.

  12. 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

  13. def ensuring(cond: (Enumeration) => Boolean, msg: => Any): Enumeration
    Implicit
    This member is added by an implicit conversion from Enumeration toEnsuring[Enumeration] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. def ensuring(cond: (Enumeration) => Boolean): Enumeration
    Implicit
    This member is added by an implicit conversion from Enumeration toEnsuring[Enumeration] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. def ensuring(cond: Boolean, msg: => Any): Enumeration
    Implicit
    This member is added by an implicit conversion from Enumeration toEnsuring[Enumeration] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  16. def ensuring(cond: Boolean): Enumeration
    Implicit
    This member is added by an implicit conversion from Enumeration toEnsuring[Enumeration] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  17. 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
  18. def equals(arg0: AnyRef): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to eq.

    See also equals in scala.Any.

    returns

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

    Definition Classes
    AnyRef → Any
  19. 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

  20. 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 Enumeration toStringFormat[Enumeration] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  21. 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()
  22. def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  23. 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
  24. final def maxId: Int

    The one higher than the highest integer amongst those used to identify values in this enumeration.

  25. 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
  26. var nextId: Int

    The integer to use to identify the next created value.

    The integer to use to identify the next created value.

    Attributes
    protected
  27. var nextName: Iterator[String]

    The string to use to name the next created value.

    The string to use to name the next created value.

    Attributes
    protected
  28. 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

  29. 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

  30. def readResolve(): AnyRef
    Attributes
    protected
  31. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  32. def toString(): String

    The name of this enumeration.

    The name of this enumeration.

    returns

    a String representation of the object.

    Definition Classes
    Enumeration → AnyRef → Any
  33. def values: ValueSet

    The values of this enumeration as a set.

  34. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  35. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  36. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  37. final def withName(s: String): Value

    Return a Value from this Enumeration whose name matches the argument s.

    Return a Value from this Enumeration whose name matches the argument s. The names are determined automatically via reflection.

    s

    an Enumeration name

    returns

    the Value of this Enumeration if its name matches s

    Exceptions thrown

    NoSuchElementException if no Value with a matching name is in this Enumeration

  38. implicit object ValueOrdering extends Ordering[Value]

    An ordering by id for values of this set

  39. object ValueSet extends SpecificIterableFactory[Value, ValueSet] with java.io.Serializable

    A factory object for value sets

    A factory object for value sets

    Annotations
    @SerialVersionUID()

Deprecated Value Members

  1. def [B](y: B): (Enumeration, B)
    Implicit
    This member is added by an implicit conversion from Enumeration toArrowAssoc[Enumeration] 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 AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromEnumeration to any2stringadd[Enumeration]

Inherited by implicit conversion StringFormat fromEnumeration to StringFormat[Enumeration]

Inherited by implicit conversion Ensuring fromEnumeration to Ensuring[Enumeration]

Inherited by implicit conversion ArrowAssoc fromEnumeration to ArrowAssoc[Enumeration]

Ungrouped