Enumeration
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 aValue method adds a new unique value to the enumeration. To be accessible, these values are usually defined asval members of the enumeration.
All values in an enumeration share a common, unique type defined as theValue 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.
Value parameters
- initial
The initial value from which to count the integers that identifies values at run-time.
Attributes
- Example
// Define a new enumeration with a type alias and work with the full set of enumerated valuesobject 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// Example of adding attributes to an enumeration by extending the Enumeration.Val classobject Planet extends Enumeration { protected case class PlanetVal(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): PlanetVal = x.asInstanceOf[PlanetVal] val G: Double = 6.67300E-11 val Mercury = PlanetVal(3.303e+23, 2.4397e6) val Venus = PlanetVal(4.869e+24, 6.0518e6) val Earth = PlanetVal(5.976e+24, 6.37814e6) val Mars = PlanetVal(6.421e+23, 3.3972e6) val Jupiter = PlanetVal(1.9e+27, 7.1492e7) val Saturn = PlanetVal(5.688e+26, 6.0268e7) val Uranus = PlanetVal(8.686e+25, 2.5559e7) val Neptune = PlanetVal(1.024e+26, 2.4746e7)}println(Planet.values.filter(_.radius > 7.0e6))// output:// Planet.ValueSet(Jupiter, Saturn, Uranus, Neptune)- Source
- Enumeration.scala
- Graph
- Supertypes
- Known subtypes
- objectRoundingMode
- Self type
Members list
Type members
Classlikes
A class implementing thescala.Enumeration.Value type.
A class implementing thescala.Enumeration.Value type. This class can be overridden to change the enumeration's naming and integer identification behaviour.
Attributes
- Source
- Enumeration.scala
- Supertypes
The type of the enumerated values.
The type of the enumerated values.
Attributes
- Source
- Enumeration.scala
- Supertypes
- Known subtypes
An ordering by id for values of this set
An ordering by id for values of this set
Attributes
- Source
- Enumeration.scala
- Supertypes
- Self type
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 parameters
- nnIds
The set of ids of values (adjusted so that the lowest value does not fall below zero), organized as a
BitSet.
Attributes
- Companion
- object
- Source
- Enumeration.scala
- Supertypes
A factory object for value sets
A factory object for value sets
Attributes
- Companion
- class
- Source
- Enumeration.scala
- Supertypes
- Self type
Value members
Constructors
Attributes
- Source
- Enumeration.scala
Concrete methods
Creates a fresh value, part of this enumeration.
Creates a fresh value, part of this enumeration, identified by the integeri.
Creates a fresh value, part of this enumeration, identified by the integeri.
Value parameters
- i
An integer that identifies this value at run-time. It must be unique amongst all values of the enumeration.
Attributes
- Returns
Fresh value identified by
i.- Source
- Enumeration.scala
Creates a fresh value, part of this enumeration, calledname.
Creates a fresh value, part of this enumeration, calledname.
Value parameters
- name
A human-readable name for that value.
Attributes
- Returns
Fresh value called
name.- Source
- Enumeration.scala
Creates a fresh value, part of this enumeration, calledname and identified by the integeri.
Creates a fresh value, part of this enumeration, calledname and identified by the integeri.
Value parameters
- 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.
Attributes
- Returns
Fresh value with the provided identifier
iand namename.- Source
- Enumeration.scala
The value of this enumeration with given idx
The one higher than the highest integer amongst those used to identify values in this enumeration.
The one higher than the highest integer amongst those used to identify values in this enumeration.
Attributes
- Source
- Enumeration.scala
Attributes
- Source
- Enumeration.scala
The name of this enumeration.
The values of this enumeration as a set.
Return aValue from thisEnumeration whose name matches the arguments.
Return aValue from thisEnumeration whose name matches the arguments. The names are determined automatically via reflection.
Value parameters
- s
an
Enumerationname
Attributes
- Returns
the
Valueof thisEnumerationif its name matchess- Throws
NoSuchElementExceptionif no
Valuewith a matching name is in thisEnumeration- Source
- Enumeration.scala
Concrete fields
The integer to use to identify the next created value.
The string to use to name the next created value.