Gets compiled to the java code public class A1 extends implements scala. Generate companion object with the same name containing an appropriate apply() and unapply() method, which are basically just a convenience constructor allowing to instantiate without using the new keyword and an extractor which by default generates an option-wrapped tuple of the case class parameters.ĮDIT: Sample compiler output for (case) classes (copied from )Ī simple scala class definition like class A1(v1: Int, v2: Double).Generate the toString(), equals() and hashcode() methods using all constructor params for each method.Convert all constructor parameters to public readonly ( val) by default fields. 0 Derive Avro schema from Scala case class generated by ScalaPB. Defining a case class A minimal case class requires the keywords case class, an identifier, and a parameter list (which may be empty): Scala 2 and 3 case class Book(isbn: String) val frankenstein Book ( '978-0486282114' ) Notice how the keyword new was not used to instantiate the Book case class. Second, they dont allow matching a subset of the fields and skipping the rest. First, they dont support using the field names in the matches, forcing us to type out each of the field patterns in definition order. 0 Type mismatch, expected: CodedInputStream, actual: FileInputStream. Scalas case classes are a bit annoying to pattern match especially when they have more than two or three fields. By default case class parameters are immutable so in your example val is automatically inferred by the compiler for the myStringVal argument. 3 hours ago &0183 &32 Save a case class in Scala to a text file and recreate it without any modification to the case class. Note, that the default visibility in scala is public. In your example, the trait MyTrait has no use, except being able to function like a java interface. class AAA(i: Int, s: String, o: OptionInt, bbb: BBB) class BBB(l: ListInt) def explainTypeT: String. You might want to check out this blog article covering what case classes exactly are and why they are so useful.
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