Trait & Mixins : Example

Traits can be used as a replacement for Interfaces. We can also Define methods, as well as Create instance fields; which is not possible with Interfaces

//PS:96
//psn > a30 > a90
scala> // An example Class

scala> class Subject {
     |   def getMathMark() = {
     |     75  
     |   }
     | }
defined class Subject

scala> 

scala> // Trait with method Declaration

scala> trait Logger {
     |   def info (msg:String):Unit    
     | }
defined trait Logger

scala> 

scala> // Trait with method Definition

scala> trait StdoutLogger extends Logger {
     |   def info(msg:String):Unit = {
     |     println(s"INFO: $msg")  
     |   }
     | }
defined trait StdoutLogger

scala> 

scala> // Mixin Class with the Trait

scala> val subjectNlogger = new Subject() with StdoutLogger {
     |   override def getMathMark() = {
     |     info("Calling getMathMark()")
     |     val mark = super.getMathMark()
     |     info(s"Exitting getMathMark() : Result -> $mark")
     |     mark
     |   }
     | }
subjectNlogger: Subject with StdoutLogger = $anon$1@73a31cbb

scala> 

scala> subjectNlogger.getMathMark()
INFO: Calling getMathMark()
INFO: Exitting getMathMark() : Result -> 75
res12: Int = 75