Enum.valueOf(String)

[Jonathan Gibbons]

Eamonn,

See 
http://docs.oracle.com/javase/7/docs/api/java/lang/Enum.html#valueOf(java.lang.Class,%20java.lang.String)

> Note that for a particular enum type T, the implicitly declared public 
> static T valueOf(String) method on that enum may be used instead of 
> this method to map from a name to the corresponding enum constant. All 
> the constants of an enum type can be obtained by calling the implicit 
> public static T[] values() method of that type.

-- Jon

On 08/20/2013 11:00 AM, Eamonn McManus wrote:
> As I mentioned earlier in the thread, it's kind of user-hostile for
> the Enum javadoc to send the user to the JLS instead of just saying,
> even briefly, what the methods are. Even more so since it doesn't
> actually link to the relevant section of the JLS or in fact to the JLS
> at all. This is not a complaint that the information isn't documented,
> just that it is too hard to find. Imagine how much work I have to do
> if I can't remember the name of the method to convert from a string to
> an enum constant in a new enum I'm writing, and it doesn't occur to me
> to pick some other random enum and look at its javadoc.
>
> Éamonn
>
>
> 2013/8/20 Jonathan Gibbons <jonathan.gibbons at oracle.com>:
>> Paul,
>>
>> Enums are well covered in JLS 7, section 8.9. In particular, see 8.9.2, Enum
>> Body Declarations, beginning at the line
>>
>> "In addition, if E is the name of an enum type, then that type has the
>> following implicitly declared static methods:"
>>
>> -- Jon
>>
>>
>> On 08/20/2013 06:27 AM, Paul Benedict wrote:
>>> Jon, it's not a problem with the method docs, per se. The issue is about
>>> how the generation isn't documented. My questioning started because I was
>>> using several enums without javadoc available, but I did have the source
>>> available, and couldn't figure out how the method came to be. Since I've
>>> asked, everyone knew (but me!) it was a generated method, but I couldn't
>>> divine that knowledge.
>>>
>>> My recommendation is to add an @implNote on Enum.valueOf(Class, String) so
>>> that people know each subclass will get a generated method that behaves
>>> similarly. What do you think?
>>>
>>>
>>> On Mon, Aug 19, 2013 at 9:23 AM, Paul Benedict <pbenedict at apache.org
>>> <mailto:pbenedict at apache.org>> wrote:
>>>
>>>      I have been working with classes that don't have javadoc
>>>      attachments. The problem was I couldn't find the method in the
>>>      source nor was the method part of the Enum class. So where did it
>>>      materialize from? Now I know the answer: the compiler generates it.
>>>
>>>      I really think this knowledge should be added to the Enum javadoc
>>>      class. I had to go on quite a goose hunt to find this fact.
>>>
>>>      Paul
>>>
>>>
>>>      On Mon, Aug 19, 2013 at 3:32 AM, Alan Bateman
>>>      <Alan.Bateman at oracle.com <mailto:Alan.Bateman at oracle.com>> wrote:
>>>
>>>          On 18/08/2013 05:07, Paul Benedict wrote:
>>>
>>>              I think the generated method needs to be listed in the
>>>              class javadoc at
>>>              least. I presume it throws an exception too (like the
>>>              other valueOf) if the
>>>              String can't be resolved to a constant, but no user is
>>>              going to discover
>>>              this fact through the documentation.
>>>
>>>          Have you checked the generated avadoc for your enum? The
>>>          valueOf(String) should be there and specified to throw IAE or NPE.
>>>
>>>          -Alan
>>>
>>>
>>>
>>>
>>>
>>>      --     Cheers,
>>>      Paul
>>>
>>>
>>>
>>>
>>> --
>>> Cheers,
>>> Paul
>>