Coding Conventions - Naming Enums

Question

Is there a convention for naming enumerations in Java   My preference is that an enum is a type   So  for instance  you have an enum   Fruit Apple Orange Banana Pear         NetworkConnectionType LAN Data 3g Data 4g          I am opposed to naming it   FruitEnum NetworkConnectionTypeEnum   I understand it is easy to pick off which files are enums  but then you would also have   NetworkConnectionClass FruitClass   Also  is there a good document describing the same for constants  where to declare them  etc

User · Answer

As already stated  enum instances should be uppercase according to the docs on the Oracle website  http   docs oracle com javase tutorial java javaOO enum html    However  while looking through a JavaEE7 tutorial on the Oracle website  http   www oracle com technetwork java javaee downloads index html   I stumbled across the  Duke s bookstore  tutorial and in a class  tutorial examples case-studies dukes-bookstore src main java javaeetutorial dukesbookstore components AreaComponent java   I found the following enum definition   private enum PropertyKeys       alt  coords  shape  targetImage      According to the conventions  it should have looked like   public enum PropertyKeys       ALT  alt    COORDS  coords    SHAPE  shape    TARGET IMAGE  targetImage         private final String val       private PropertyKeys String val            this val   val              Override     public String toString             return val            So it seems even the guys at Oracle sometimes trade convention with convenience

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This will probably not make me a lot of new friends  but it should be added that the C  people have a different guideline  The enum instances are  Pascal case   upper lower case mixed   See stackoverflow discussion and MSDN Enumeration Type Naming Guidelines   As we are exchanging data with a C  system  I am tempted to copy their enums exactly  ignoring Java s  constants have uppercase names  convention  Thinking about it  I don t see much value in being restricted to uppercase for enum instances  For some purposes  name   is a handy shortcut to get a readable representation of an enum constant and a mixed case name would look nicer   So  yes  I dare question the value of the Java enum naming convention  The fact that  the other half of the programming world  does indeed use a different style makes me think it is legitimate to doubt our own religion

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enum MyEnum  VALUE 1 VALUE 2    is  approximately  like saying  class MyEnum        public static final MyEnum VALUE 1   new MyEnum  VALUE 1        public static final MyEnum VALUE 2   new MyEnum  VALUE 2         private final name       private MyEnum String name            this name   name             public String name     return this name       so I guess the all caps is strictly more correct  but still I use the class name convention since I hate all caps wherever

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If I can add my  0 02  I prefer using PascalCase as enum values in C   In C  they are basically global  and PEER CONNECTED gets really tiring as opposed to PeerConnected   Breath of fresh air   Literally  it makes me breathe easier   In Java  it is possible to use raw enum names as long as you static import them from another class   import static pkg EnumClass      Now  you can use the unqualified names  that you qualified in a different way already   I am currently  thinking  about porting some C code to Java and currently  torn  between choosing Java convention  which is more verbose  more lengthy  and more ugly  and my C style   PeerConnected would become PeerState CONNECTED except in switch statements  where it is CONNECTED   Now there is much to say for the latter convention and it does look nice but certain  idiomatic phrases  such as if  s    PeerAvailable  become like if  s    PeerState AVAILABLE  and nostalgically  this is a loss of meaning to me   I think I still prefer the Java style because of clarity but I have a hard time looking at the screaming code   Now I realize PascalCase is already widely used in Java but very confusing it would not really be  just a tad out of place

User · Answer

Enums are classes and should follow the conventions for classes  Instances of an enum are constants and should follow the conventions for constants  So   enum Fruit  APPLE  ORANGE  BANANA  PEAR     There is no reason for writing FruitEnum any more than FruitClass  You are just wasting four  or five  characters that add no information   Java itself recommends this approach and it is used in their examples

User · Answer

In our codebase  we typically declare enums in the class that they belong to   So for your Fruit example  We would have a Fruit class  and inside that an Enum called Fruits   Referencing it in the code looks like this   Fruit Fruits Apple  Fruit Fruits Pear  etc   Constants follow along the same line  where they either get defined in the class to which they re relevant  so something like Fruit ORANGE BUSHEL SIZE   or if they apply system-wide  i e  an equivalent  null value  for ints  in a class named  ConstantManager   or equivalent  like ConstantManager NULL INT     side note  all our constants are in upper case   As always  your coding standards probably differ from mine  so YMMV

User · Answer

They re still types  so I always use the same naming conventions I use for classes   I definitely would frown on putting  Class  or  Enum  in a name   If you have both a FruitClass and a FruitEnum then something else is wrong and you need more descriptive names   I m trying to think about the kind of code that would lead to needing both  and it seems like there should be a Fruit base class with subtypes instead of an enum    That s just my own speculation though  you may have a different situation than what I m imagining    The best reference that I can find for naming constants comes from the Variables tutorial      If the name you choose consists of only one word  spell that word in all lowercase letters  If it consists of more than one word  capitalize the first letter of each subsequent word  The names gearRatio and currentGear are prime examples of this convention  If your variable stores a constant value  such as static final int NUM GEARS   6  the convention changes slightly  capitalizing every letter and separating subsequent words with the underscore character  By convention  the underscore character is never used elsewhere

[java] Coding Conventions - Naming Enums

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