在Scala中实现基于类型的行为的最佳方法

Question

In a friendly chat that I was having with a friend during a code review we notice that in the code there was a lot of:

unknownTypeVal match {
    case asStr: String => //DO SOMETHING FOR STRING
    case asInt: Integer => //DO SOMETHING FOR Integer
    case asMyOwnClass: MyOwnClass => //DO SOMETHING FOR MyOwnClass
}

problem that was initially generated by methods that return Any or Option and there is no way to remove that because we are using libraries as XPath, and JSONPath, which return instances of Any or Option for a provided path.

I don't want to get into discussions of "preference" , this is not an opinion question, I want to know either by standard defined preferably by Scala, or any other organization of impact, to do this kind of "type checking" in code in a more organized way, we think that this functionality can be reduced to a single function call to a method which contains a map of function and based on "something" (name of the class or something else that I do not know right now) determine how to process such parameter:

process(myAnnonimusVal: Any) = myMapOfFunct(myAnnonimusVal.getClass) //and based on the function that this will return execute such function pasing myAnnonimusVal

what is encouraged to do by Scala devs or Scala community

Answer 1

In principle, match is the cleanest way to execute code conditional on matching the Any type to something else. Any chain of if-else, instanceOf, etc is bound to turn out to be even more cumbersome and less elegant. A possible exception is a case where you know what the actual type is and can act accordingly, where a direct cast might be permissible.

That said, if you find yourself making the same matches many times, you might as well encapsulate the match in order to avoid code repetition. A partial function might be exactly what you have in mind here.