VarArgs - Best Practice

[lemmi]

Hi,

I have a question regarding the usage of variable arguments (VarArgs).
I am developing a framework and several of the classes in this
framework allow the developer to 'add' objects to them. One way of
implementing this is by passing a collection, an array, or a variable
argument. Is there a best practise on how to implement this?

Example:

Option 1: addMyObjects(Collection<MyObject> objects);

Option 2: addMyObjects(MyObject[] objects);

Option 3: addMyObjects(MyObject... objects);

I like option 3 because this way the developer can pass a single
object very easily without the need of creating an array.

Your thoughts?

--Dirk

 

[Roedy Green]

I like option 3 because this way the developer can pass a single
object very easily without the need of creating an array.

Your thoughts?

Have a look at how EnumSet works. They have dozens of overloaded
methods. They have one, two, three parms, varargs, collection ...
To the user, you can throw anything reasonable at it.

 

[Daniel Pitts]

Hi,

I have a question regarding the usage of variable arguments (VarArgs).
I am developing a framework and several of the classes in this
framework allow the developer to 'add' objects to them. One way of
implementing this is by passing a collection, an array, or a variable
argument. Is there a best practise on how to implement this?

Example:

Option 1: addMyObjects(Collection<MyObject> objects);

Option 2: addMyObjects(MyObject[] objects);

Option 3: addMyObjects(MyObject... objects);

I like option 3 because this way the developer can pass a single
object very easily without the need of creating an array.

Your thoughts?

--Dirk

I would prefer Collection<MyObject> personally. using [] or ... is
the primative obsession codesmell (Refactory p.81, Fowler, 2006)

 

[Daniel Dyer]

Hi,

I have a question regarding the usage of variable arguments (VarArgs).
I am developing a framework and several of the classes in this
framework allow the developer to 'add' objects to them. One way of
implementing this is by passing a collection, an array, or a variable
argument. Is there a best practise on how to implement this?

Example:

Option 1: addMyObjects(Collection<MyObject> objects);

Option 2: addMyObjects(MyObject[] objects);

Option 3: addMyObjects(MyObject... objects);

I like option 3 because this way the developer can pass a single
object very easily without the need of creating an array.

I would usually prefer the first approach (either Collection<MyObject>,
List<MyObject> or Set<MyObject> as appropriate).

The varargs approach is OK as long as you aren't using generics. This
situation is a special case of "generics and arrays don't mix". Consider
the method:

addMyObjects(MyObject<E>... objects)

Nothing wrong with that declaration. The problem comes when you try to
invoke the method. Invocations will generate a compile-time warning about
(implicit) "generic array creation". Of course, you can suppress the
warnings but you have to do that in every place that the method is invoked.

Dan.