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Avro >> mail # user >> Best practices for java enums...?


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Re: Best practices for java enums...?
If you use Avro IDL then you can more easily maintain long, multi-line
comments for your enum.

http://avro.apache.org/docs/current/idl.html#minutiae_comments

IDL files (.avdl) can be compiled to Schemas (.avsc) by Maven, which
are then compiled to Java.

Documentation per enum symbol is not currently supported, but would
not be difficult to add.  Please file an issue in Jira if you'd like
to see this.  For compatibility, in Json, this would probably appear
as a parallel array of documentation strings, e.g., something like:

("name": "Foo", "type":"enum", "doc":"an enum", "symbols":["X","Y"],
"symbols-doc":["X is X", "Y is Y"]}

Doug

On Thu, May 9, 2013 at 4:39 PM, Felix GV <[EMAIL PROTECTED]> wrote:
> Hello,
>
> I'm currently writing an avro schema which includes an enum field that I
> already have as a java enum in my application.
>
> At first, I named the avro field with the same fully qualified name (package
> name dot enum name) as my existing java enum. I then ran the avro compiler
> and found that it overwrote my existing java enum with an avro-generated
> enum.
>
> I find this slightly annoying because my java enum had comments documenting
> the purpose of each enum value, and the avro-generated enum doesn't have
> this.
>
> I see two or three potential solutions:
>
> Accepting to replace my current enum with the avro-generated one in my code
> base, which I feel I cannot document properly (since I have access to just
> one doc attribute for the whole enum, instead of per symbol). On a side
> note, I haven't found any way to have a multi-line doc attribute in an avro
> schema, so that makes things slightly more annoying still. I wouldn't mind
> settling on using the avro-generated enums without documentation per symbol
> if at least I could have one big doc/comment that documents all symbols at
> once, but since it seems the doc attribute must be a one-liner, this is
> starting to be a little too messy for my taste...
> Maintaining two separate enums: my manually written (and documented) enum as
> well as the avro-generated enum. For now, I think this is what I'm going to
> do, because those enums have little chances of changing anyway, but from a
> maintenance standpoint, it seems pretty horrendous...
> I guess there's a third way, which would involve creating a script that
> backs up my enums, compiles all my schemas, and then restores my backed up
> enums, but this also seems ultra messy :( ... I haven't tested if it'd work
> (since the manually written enum is missing the $SCHEMA field), but I guess
> it would...
>
> Am I being OCD about this? or is this a concern that others have bumped
> into? How do you guys deal with this? Did I miss anything in the way avro
> works?
>
> P.S.: I've seen that reflect mappings may be able to work with arbitrary
> java enums, but since they seemed discouraged for performance reasons, I
> haven't digged much in this direction. I'd like to keep using .avsc files if
> possible, but if there's a better way, I can certainly try it.
>
> P.P.S.: We're currently using avro 1.6.1, but if the latest version provides
> a nice way of handling my use case, then I guess I could get us to
> upgrade...
>
> Thanks a lot :) !
>
> --
> Felix
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB