scala - Is it possible to update fields of any case class implementing a common trait -


Assume that we have a common property model. 

  Property Model {def id: string df update: date}   
 And we have 2 case classes to extend this case. Case class C1 (ID: string, updated: date, foo: string) Model Case Class C2 (ID: string, updated: date, bar: enter) model Enhance   
 Is it possible to write a utility function as below, which takes the model as a parameter and returns a copy with an update for the updated fields?  
  Object model {def update [T> << Model> (Model: T): T = {model.copy (updated = new date) // This code does not compile. There are two problems with your code:  
       
     
     is not defined on the  copy  attribute, so there is a need to define some of the properties that you can use.  
  1.  Return a  model  instead of  T  for  update , every  model  on its actual Subtype should know.   
     You can do the model: [T]] {DIF ID: string DEF UPDATE: with date DRF date (D: Date): T} Case Class C1 (for example ):  
      id: string, updated: date, foo: string) model [c1] {def withDate (d: date) = copy (updated = d)} case class C2 (id: String, updated: Date, bar: int) is extending model [C2] {def withDate (d: Date) = copy (updated = d)} Object model {def update [T>: Model [T]] ( Model: T): T = {model.withDate (new date)) // This code does not compile. }}   
     So now it works:  
      scala> Val C1 = C1 ("Exam", New Date, "FU") C1: C1 = C1 (Test, Mon 21 Apr 10:25:10 CDT 2014, FU) Scale & gt; Model.update (c1) res0: C1 = C1 (test, Mon 21 Apr 10:25:17 cdt 2014, af)    

     

    2.

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