Here we discuss How Enum Function Work in Scala and Examples, along with the codes and outputs. We can also assign some default values to the enum constant that would be the id for enum values. Also, if we want to define enum values, we have to use the val keyword because to make it accessible.
There is also no attribute access either. What I notice is that enum is not yet a monad, so there is no flatMap and get, and there is no predefined apply and unapply function. Instead, we have an Enumeration class that we need to extend. enum Task: case CleaningTask () extends Task case CookingTask () extends Task case ShoppingTask () extends Task. In scala enum, we do not have any keyword named enum like other programming languages. For this, we are using the enum name followed by the values method. After that, we are printing out the values that we have assigned to the constant. In fact, Scala's Enumeration class supports the usual methods for working with collections, so we can easily iterate through the breeds with a for loop and. Once created we are assigning values to the enum by using the type and Values keyword. If we do not do this compile-time error will be generated. The first thing we need to keep in mind while creating enum is we have to extend the enumeration class. Lets’s take a look at its supertypes, subclass, and hierarchy īelow is one example which will explain its working what we are doing here is we are creating one enum with values like the name of the day. Therefore, all the values that we define inside the enum would be representing a common and share a common category. While defining the value of an enum, we are using the val keyword to make the value easily accessible.
The enum class starts with a compiler-generated import that imports the namesFor this scala, the enum provides methods to work with it. expands to a sealed abstract class that extends the trait and an associated companion object that contains the defined cases, expanded according to rules (2 - 8). The advantage of enum classes is that they can be serialized and deserialized out of the. Since those classes can be object declarations, we can use sealed classes to a certain degree instead of enums, but not the other way around. We can also fetch the value of an enum constant. Enum classes represent a concrete set of values, while sealed classes represent a concrete set of classes. This enum in the future will provide a lightweight alternative value to the requested classes. They are basically a set of finite values, and these values are an enumerated form of a defined enum can take. Scala enum is worked in the same way as any other programming language. In this, we are trying to create an enum that represents the month name.
Val Jan, Feb, Mar, Apr, May, Jun, Jul Aug, Sep, Oct, Nov, Dec = Value Enums are represented as sealed classes that extend the trait. In the test, the enums are defined in the MainScala.scala file and used from a Java source, Test.java.
After that, we can define values that will be part of the enum. For a more in-depth example of using Scala 3 enums from Java, see this test. While defining enum, we need to use type alias as well. For that, we need to extend this class and give a name to the enum. In scala, we have an enumeration class to create enum. Val constant1, constant2, constant3, and so on.
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While less succinct than a Java enum declaration, ADTs have more expressive power as members of the base type (in our example Shape) can be defined to take arbitrary arguments.Start Your Free Software Development Course Most people I know of instead chooses to create an algebraic datatype (commonly referred to as an ADT)Ĭase object Square(side: Int) extends ShapeĬase object Rectangle(width: Int, height: Int) extends Shape In the standard library you have scala.Enumeration, a trait which you may extend to create an enum-like type. default do double else enum extends final finally float for if implements. The truth is that Scala lacks language support for enums, and so users use different solutions based on their need. Java Abstraction Java Interface Java Enums Java User Input Java Date Java.