Java enum - why use toString instead of name

Question

If you look in the enum api at the method name   it says that      Returns the name of this enum constant  exactly as declared in its enum declaration             Most programmers should use the toString method in preference to this one             as the toString method may return a more user-friendly name            This method is designed primarily for use in specialized situations where correctness depends on getting the exact name  which will not vary from release to release    Why is better to use toString    I mean toString may be overridden when name   is already final  So if you use toString and someone overrides it to return a hard-coded value your whole application is down    Also if you look in the sources the toString   method returns exactly and just the name  It s the same thing

User · Answer

Use name   when you want to make a comparison or use the hardcoded value for some internal  use in your code   Use toString   when you want to present information to a user  including a developper looking at a log   Never rely in your code on toString   giving a specific value  Never test it against a specific string  If your code breaks when someone correctly changes the toString   return  then it was already broken   From the javadoc  emphasis mine        Returns a string representation of the object  In general  the   toString method returns a string that  textually represents  this   object  The result should be a concise but informative representation   that is easy for a person to read  It is recommended that all   subclasses override this method

User · Answer

You can also use something like the code below  I used lombok to avoid writing some of the boilerplate codes for getters and constructor    AllArgsConstructor  Getter public enum RetroDeviceStatus       DELIVERED 0  Delivered        ACCEPTED 1   Accepted        REJECTED 2   Rejected        REPAIRED 3   Repaired         private final Integer value      private final String stringValue        Override     public String toString             return this stringValue

User · Answer

name   is a  built-in  method of enum  It is final and you cannot change its implementation  It returns the name of enum constant as it is written  e g  in upper case  without spaces etc    Compare MOBILE PHONE NUMBER and Mobile phone number  Which version is more readable  I believe the second one  This is the difference  name   always returns MOBILE PHONE NUMBER  toString   may be overriden to return Mobile phone number

User · Answer

name   is literally the textual name in the java code of the enum  That means it is limited to strings that can actually appear in your java code  but not all desirable strings are expressible in code  For example  you may need a string that begins with a number  name   will never be able to obtain that string for you

User · Answer

While most people blindly follow the advice of the javadoc  there are very specific situations where you want to actually avoid toString    For example  I m using enums in my Java code  but they need to be serialized to a database  and back again  If I used toString   then I would technically be subject to getting the overridden behavior as others have pointed out   Additionally one can also de-serialize from the database  for example  this should always work in Java   MyEnum taco   MyEnum valueOf MyEnum TACO name      Whereas this is not guaranteed   MyEnum taco   MyEnum valueOf MyEnum TACO toString      By the way  I find it very odd for the Javadoc to explicitly say  most programmers should   I find very little use-case in the toString of an enum  if people are using that for a  friendly name  that s clearly a poor use-case as they should be using something more compatible with i18n  which would  in most cases  use the name   method

User · Answer

It really depends on what you want to do with the returned value    If you need to get the exact name used to declare the enum constant  you should use name   as toString may have been overriden If you want to print the enum constant in a user friendly way  you should use toString which may have been overriden  or not      When I feel that it might be confusing  I provide a more specific getXXX method  for example   public enum Fields       LAST NAME  Last Name    FIRST NAME  First Name         private final String fieldDescription       private Fields String value            fieldDescription   value             public String getFieldDescription             return fieldDescription

User · Answer

A practical example when name   and toString   make sense to be different is a pattern where single-valued enum is used to define a singleton  It looks surprisingly at first but makes a lot of sense   enum SingletonComponent       INSTANCE     configuration                   behavior             Override     String toString           return  SingletonComponent      better than default  INSTANCE            In such case   SingletonComponent myComponent   SingletonComponent INSTANCE  assertThat myComponent name    isEqualTo  INSTANCE       blah assertThat myComponent toString    isEqualTo  SingletonComponent       better

[java] Java enum - why use toString instead of name

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