Imagine another scenario where you are complaining to your best friend about the dog who lives in the apartment above you. Using Enum.compareTo() method. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. However, there was a nasty bug (BugId 6277781) in Sun JDK 6u10 and earlier that might be interesting for historical reasons. if (ErrorLevel.ERROR.compareTo (someOtherLevel) <= 0) { . } Asking for help, clarification, or responding to other answers. 3 Answers Sorted by: 47 You can do this: PinSize.BIGGEST.ordinal () > PinSize.BIG.ordinal () // evaluates to `true` Of course, assuming that BIGGEST was declared after BIG in the enumeration. Which is the best way to compare enums in Java? Here's an example of how you can use the equals () method to compare enum members: Just one thing to add to all the other excellent answers. We can use this to compare enum values. Making statements based on opinion; back them up with references or personal experience. Read more Java 5 first introduced the enum keyword. Comparing Java enum members: == or equals ()? Using == operator. Breaking this assumption results in a NullPointerException. Not the answer you're looking for? Why can you not divide both sides of the equation, when working with exponential functions? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. This abstract class defines the name () method to return an enum instance's name: We and our partners use cookies to Store and/or access information on a device. Sometimes I call him that dog upstairs or the barking menace or, sometimes when Im tired and trying to sleep, THAT DARN DOG WHO WONT STOP BARKING!. PinSize.BIGGEST and PinSize.BIGGERER are reference variables. Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. So is it correct to say that it's not possible to use '<' nor '>' operators because PinSize.BIGGEST is a reference (represents address in memory) and there's no point in comparing memory address's and it's the same for all the other references (Object, String, int[], etc.)? int[] array; ? The == operator checks the type and makes a null-safe comparison of the same type of enum constants. If not, anyone who calls isFrenchBulldog() is going to get a nasty NullPointerException when they least expect it. I don't know if it's correct or not. How can't we compare two enum values with '<'? The main aim of this article is to give you idea about how to declare a string in java and about different ways of declaring. Then, if you start using instances of Impl1, you'll have a lot of code to change and test because of previous usage of ==. Using the syntax above, we've created ten static, final instances of the enum named Element. How can we compare a StringBuilder with StringBuffer in Java? @AndrejBuday Please read the source code for. Why Extend Volume is Grayed Out in Server 2016? e.g. Of course, assuming that BIGGEST was declared after BIG in the enumeration. I ran this test several times with both IFs one at a time. After all, they are the same breed, the same matte blue/black color, and they both have the name Blue. See the example below. How would life, that thrives on the magic of trees, survive in an area with limited trees? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. equals () method returns true if the specified object is equal to this enum constant. Check equality of a ENUM value with a String in JAVA. Object Equality means these two things are identical, but separate like the twin matching French Bulldogs. For example, here are the first two rows of the periodic table as a simple enum: public enum Element { H, HE, LI, BE, B, C, N, O, F, NE } Copy. Although we don't need to instantiate an enum using new, it has the same capabilities as other classes. Compare with == Example to . On one hand, it has advantages to use ==, as described in the other answers. The == (equal) operator is a binary operator that requires two operands. Yes, I agree! Why does tblr not work with commands that contain &? Are glass cockpit or steam gauge GA aircraft safer? Instead, this dog mostly spends its days at the window furiously defending their owner from passing cars. For these reasons, use of == should be preferred to equals(). In the Java programming language Enums have a unique position. (The equals method in Enum is a final method that merely invokes super.equals on its argument and returns the result, thus performing an identity comparison. Using anything other than == to compare enum constants is nonsense. I want to complement polygenelubricants answer: I personally prefer equals(). CompareTo () Method. That means this operator is null safe and better to use than the equals() method. I would not recommend this solution, because if you change the order or add or remove elements to the enum later, you are f*ed. So, if you instead use the operator == you will have a compilation error: operator == cannot be applied to "second.pckg.Category", "first.pckg.Category". How terrifying is giving a conference talk? In the Following Java program, the displayPrice() method accepts a constant of the enum Vehicles and, compares it with all the other constants in Vehicles using the == operator and, displaces the value of the particular constant (price) incase of a match. How would life, that thrives on the magic of trees, survive in an area with limited trees? These dogs are twins in every possible way, but they are not the same dog. 1.Enum is a collection of named integer constant means it's each element is assigned by integer value. State.AL.name() returns string "AL". Same mesh but different objects with separate UV maps? In Java, the most problematic issue is handling null values. How to change what program Apple ProDOS 'starts' when booting. The problem here is that there is never a valid reason to compare breed.equals(CatBreed.TIGER) No value you can supply would ever make that condition true because dogs just cant be cats. Learn Java and Programming through articles, code examples, and tutorials for developers of all levels. I am trying to change the color by using an enum, I am comparing an enum to an int but it keeps throwing an error, How do I compare an int to an enum? Comparing Java enum members Use == (or !=) to Compare Java Enums Java.lang.Enum. Returns a positive integer, if this enum is greater than the defined object. Using == and .equals() is both valid. In this video, you will know 2 Best way java enum comparison method, and understand how to compare it in a safe way. 1. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Temporary policy: Generative AI (e.g., ChatGPT) is banned, How can we compare a string with the values of enum elements in Java, Take an array of values and compare them to Enum values in java. @miller.bartek right, you can't compare references using, Pointer comparison indeed does not make any sense, but the question boils down to why Java does not define. We can compare enum variables using the following ways. Is it legal to not accept cash as a brick and mortar establishment in France? Find centralized, trusted content and collaborate around the technologies you use most. So, I'm not sure which solution fits the best for the OPs real problem. For the official documentation on usage, we can head over to the documentation. For what its worth, the actual Java implementation of the Enum.equals() method is only one line, and its just a one line Reference Equality == comparison so. Another option is the Objects.equals utility method. Another reason is that using == to compare enums enforces type safety on the comparison. 3 Answers Sorted by: 26 try this public void setState (String s) { state = State.valueOf (s); } You might want to handle the IllegalArgumentException that may be thrown if "s" value doesn't match any "State" Share Improve this answer Comparing Enum values in Java The common sense rule in Java is that when comparing things, objects always get compared with objectA.equals (objectB) , and primitives get compared with. Zerk caps for trailer bearings Installation, tools, and supplies. How to draw a picture of a Periodic function? equals() method returns true if the specified object is equal to this enum constant. I know that Java enums are compiled to classes with private constructors and a bunch of public static members. Asking for help, clarification, or responding to other answers. Yes: enums have tight instance controls that allows you to use == to compare instances. Syntax public final int compareTo (E o) Parameters o - It is the enum object that is compared Return Value The compareTo () method returns: Use Reference Equality == checks when comparing Enums. What is the logic used by Objects.equals? Following is the declaration for java.lang.Enum class -. Rivers of London short about Magical Signature. Do any democracies with strong freedom of expression have laws against religious desecration? If you look at the source code for .equals(), it simply defers to ==. Returns zero, if this enum is equal to the defined object. All Rights Reserved. And it could be be a bit difficult to see. Not the answer you're looking for? However, if we work with the == (equals) operator and compare enum values/objects, it will not throw the nullpointerexception. No matter where in your codebase you write DogBreed.FRENCHBULLDOG you are always guaranteed to get back exactly the same object. Copyright Tutorials Point (India) Private Limited. How to compare list of string with enum string values without Map or switch case? The common sense rule in Java is that when comparing things, objects always get compared with objectA.equals(objectB) , and primitives get compared with primitiveA == primitiveB. Making statements based on opinion; back them up with references or personal experience. Switch-Case Statement == Operator .equals () method Also if you have below questions then you are at right place. Enumeration (Enum) in Java was introduced in JDK 1.5 and it is one of my favorite features of J2SE 5 among Autoboxing and unboxing, Generics, varargs, and. Last but not least, the == on enums is arguably more readable (less verbose) than equals(). What does this question have to do with the SCJP/OCPJP? We often create an enum as a simple list of values. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. Future society where tipping is mandatory, How to change what program Apple ProDOS 'starts' when booting. When comparing two members of a given enum, I've always used .equals(), e.g. Here's the guarantee provided by the language specification (emphasis by me): An enum type has no instances other than those defined by its enum constants. Passport "Issued in" vs. "Issuing Country" & "Issuing Authority". Rivers of London short about Magical Signature, Most appropriate model for 0-10 scale integer data. Distances of Fermat point from vertices of a triangle. The reason enums work easily with == is because each defined instance is also a singleton. Are Tucker's Kobolds scarier under 5e rules than in previous editions? Intuitively you would say those dogs are the same. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. That said, with enums & constants, == is the most readable option, as the answer points out. In Java, you can use == operator to compare Enum value. Together, these four things ensure that no instances of an enum type exist beyond those defined by the enum constants. In the case of enum values, the "size" depends on the order of the enum value definitions. Thanks for contributing an answer to Stack Overflow! On the other hand, if you for any reason replace the enums with a different approach (normal class instances), having used == bites you. Java Enum example. You can compare the members of two enums using the == operator or the equals() method.