Scala案例类

Question

Below is the code snippet:

package caseClassExp

sealed trait Resources  {
  def fullpath :String
}

case class Folder (name :String ,
    path :Option[String] = None) extends Resources {
    def fullpath :String = path match {
      case Some(p) => List(p, name).mkString("/")
      case None => s"./$name"
    }
}

case class File (name :String ,
      folder :Option[Folder] = None ) extends Resources {
  def fullpath :String = folder match {
    case Some(f) => List(f.fullpath, name).mkString("/")
    case None => s"./$name"    
  }
}

object caseClass {
  def main(agrs:Array[String]):Unit = {
 
val resources = Seq[Resources] (
File("ex1.Scala",Some(Folder("example",Some("~/Dev"))))
Folder("temp")
Folder("bin",Some("/usr"))
File(".Clouder")
)  

resources foreach {
  case f :File => println(s"File: ${f.fullpath}")
  case f:Folder  => println(s"FOlder : ${f.fullpath}")
 }
}
}

When I am calling File and Folder method (defined as case class) in main I am getting error, I am not sure what I am doing wrong.

Answer 1

So your sequence is incorrect.

You should put a comma after every element in your sequence.

val resources = Seq[Resources] (
  File("ex1.Scala",Some(Folder("example",Some("~/Dev")))),
  Folder("temp"),
  Folder("bin",Some("/usr")),
  File(".Clouder")
)

And the result:

File: ~/Dev/example/ex1.Scala
FOlder : ./temp
FOlder : /usr/bin
File: ./.Clouder

So everything is okay :) Except that commas

In your code, my proposal is to add type to resources and use only Seq to create a sequence. The code will be more readable.

val resources: Seq[Resources] = Seq(
  File("ex1.Scala",Some(Folder("example",Some("~/Dev")))),
  Folder("temp"),
  Folder("bin",Some("/usr")),
  File(".Clouder")
)