Interface naming convention [closed]

Answer 1

Because you usually have an IThing and a Thing. So instead of letting people come with their own "conventions" for this recurring situation, a uniform one-size-fits all convention was chosen. Echoing what others say, the de facto standardness is reason enough to use it.

Answer 2

Do prefix interface names with the letter I to indicate that the type is an interface.

The guideline doesn't explain why you should use the I prefix, but the fact that this is now an established convention should be reason enough.

What do you have to gain by dropping the I prefix?

Answer 3

Thing is more readable name than IThing. I'm from the school of thought that we should program to interfaces rather than specific implementations. So generally speaking, interfaces should have priority over implementations. I prefer to give the more readable name to the interface rather than the implementation (i.e., my interfaces are named without the 'I' prefix).

Answer 4

I don't know exactly why they chose that convention, perhaps partly thinking of ensouling the class with "I" as in "I am Enumerable".

A naming convention that would be more in the line of the rest of the framework would be to incorporate the type in the name, as for example the xxxAttribute and xxxException classes, making it xxxInterface. That's a bit lengthy though, and after all the interfaces is something separate, not just another bunch of classes.

Answer 5

I think it is better than adding a "Impl" suffix on your concrete class. It is a single letter, and this convention is well established. Of course you are free to use any naming you wish.

Answer 6

I know the Microsoft guidelines recommends using the 'I' to describe it as an interface. But this comes from IBM naming conventions if I'm not remember wrong, the initiating 'I' for interfaces and the succeeding *Impl for the implementations.

However, in my opinion the Java Naming Conventions is a better choice than the IBM naming convention (and not only in Java, for C# as well and any OO programming language). Interfaces describes what an object can be able to do if it implements the interface and the description should be in verb form. I.e Runnable, Serializable, Invoiceable, etc. IMHO this is a perfect description of what the interface represents.