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Overriding equals method in Scala


Overriding equals method in Scala

By : RajC
Date : November 16 2020, 06:23 AM
Hope that helps email is only a constructor parameter and not a member of the class itself. You can make it as such by preceding it with val
code :
class Player(val email: String) {
  override def equals(player: Any): Boolean = {
    player match {
      case p: Player => email.equals(p.email)
      case _ => false
    }
  }
}
class Player(e: String) {
  val email: String = e
  ...
}
class Player(e: String) {
   def email: String = e
   ...
}
class Player(private val email: String) 


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Scala: Problems with erasure on overriding equals function for parametrized classes

Scala: Problems with erasure on overriding equals function for parametrized classes


By : polymagnus
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , You can't fix it. Welcome to the joys of smooth interoperation with java. The only way to improve equals from def equals(x: Any): Boolean is to write a different method.
I'm always trying to convince martin that we should implement == desugaring differently, aiming at something like "def decentEquals[T](x: T)(implicit equiv: Equiv[T])" with default implicits and bridge methods to make it seamless unless you care, but he thinks equality tests shouldn't get any slower.
Scala: Overriding equals for value classes

Scala: Overriding equals for value classes


By : Geir Ole Aagedal
Date : March 29 2020, 07:55 AM
it should still fix some issue I don't think == can be made to work in this situation. What you might do is define a different comparison operation.
code :
case class Name(value: String) extends AnyVal {
  def is(n: Name): Boolean = value == n.value
}
implicit def toName(something:String): Name = Name(something) // not in object
val somebody = Person("Pete", "Street 1")
somebody.move(Address("Street 2")) // allowed
somebody.move("Street 2") // allowed by convenience
somebody.name is "Pete"   // true
"Pete" is somebody.name   // true
Overriding equals and hashCode methods for a JavaBeans implemented in Scala

Overriding equals and hashCode methods for a JavaBeans implemented in Scala


By : user3806821
Date : March 29 2020, 07:55 AM
will be helpful for those in need If the properties are var, and are expected to change, and you want to change hashCode because it is used for caching, then, my friend, you have a problem.
If you base your hashCode on something that will change, the next time you try to look it up it will most likely fail to find your object, as the hashCode will have changed, and it will look for it on the wrong place.
Overriding the Equals in Scala

Overriding the Equals in Scala


By : Pab.ol
Date : March 29 2020, 07:55 AM
hope this fix your issue I need to have a custom equal method for a few of case classes. After some online searching, I haven't see any definite solution. Shall I write my own method of equality check? , Yes. You will need to define your own equals method:
scala: overriding equals of basic types

scala: overriding equals of basic types


By : demented hedgehog
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further How it can possibly be done with implicits (note that neither == nor equals can be used here):
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