Enums contains only constants and can be compared directly with ==. So, only reference check is needed, no need to use .equals method. Moreover, if .equals used incorrectly, may raise the NullPointerException while that's not the case with == check. enum Day { GOOD, AVERAGE, WORST; } public class Test { public static void main(String[] args) { Day day = null; if (day.equals(Day.GOOD)) {//NullPointerException! System.out.println("Good Day!"); } if (day == Day.GOOD) {//Always use == to compare enum System.out.println("Good Day!"); } } }To group, complement, range the enum values we have EnumSet class which contains different methods.
 xxtesaxx answer at 2017-05-19
The trick is to not actually check with == but rather use the case keyword in conjunction with a single = in your if statement. This is a little counter intuitive in the beginning but just like if let, you get used to it pretty fast: enum Normal { case one case two, three } enum NormalRaw: Int { case one = 1 case two, three } enum NormalArg { case one(Int) case two, three } let normalOne = Normal.one let normalRawOne = NormalRaw.one let normalArgOne = NormalArg.one(1) if case .one = normalOne { print("A normal one") //prints "A normal one" } if case .one = normalRawOne { print("A normal \(normalRawOne.rawValue)") //prints "A normal 1" } if case .one(let value) = normalArgOne { print("A normal \(value)") //prints "A normal 1" } The point is that in Swift you only get equation of enums for free if your enum uses a raw type or if you have no associated values (try it out, you can't have both at the same time). Swift however does not know how to compare cases with associated values - I mean how could it? Let's look at this example: Normal.one == .one //true Normal.one == .two //false NormalRaw.one == .one //true NormalRaw.one == .two //false NormalArg.one(1) == .one(1) //Well...? NormalArg.one(2) == .one(1) //Well...? NormalArg.one(1) == .two //Well...? Maybe this makes it clearer why this cannot work out of the box: class Special { var name: String? var special: Special? } enum SpecialEnum { case one(Special) case two } var special1 = Special() special1.name = "Hello" var special2 = Special() special2.name = "World" special2.special = special1 SpecialEnum.one(special1) == SpecialEnum.one(special2) //Well...? So if you want enums with associated values, you'll have to implement Equatable protocol in your enum by yourself: enum NormalArg: Equatable { case one(Int) case two static func ==(lhs: NormalArg, rhs: NormalArg) -> Bool { switch (lhs, rhs) { case (let .one(a1), let .one(a2)): return a1 == a2 case (.two,.two): return true default: return false } } }
Sometime back I’ve written an article on Java eNum – Why and for what should I use Java eNum? What is an eNum type?It is a special data type to which we could assign predefined constants to variable. In this tutorial we will go over how to compare eNums in your production application. As previous tutorial gives you complete example and details on eNum, this tutorial provides complete insight on comparison part. There are three ways we could compare eNum in Java.
Also if you have below questions then you are at right place.
Let’s get started:Step-1Create eNum CrunchifyCompany.java in Eclipse IDE.
Step-2Create class CrunchifyCompanyEnumTest.java which implements comparison methods using equals (==) and using switch case.
Step-3Run the program to see result.
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