Coding Conventions - Naming Enums

Question

Hi all,

Is there a document describing how to name enumerations?

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.?

Walter

Answer 1

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.

Answer 2

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.

Answer 3

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.