On 14/11/2012 14:30, Nigel Deakin wrote:
> Thanks for the comments. I think we should keep this list as small as possible, but I am now proposing that we require
> support for
>
> * Java letters
> * Java digits
> * Underscore (_)
> * Full stop/period (.)
> * Minus/hyphen (-)
>
> Note that this does not prevent JMS providers from supporting additional characters. This would be just defining a set
> that is guaranteed to be supported.
>
> Remember this is to allow a RA or an EJB container to generate subscription names automatically. It would also be useful
> if JMS specified that a JMS provider must support subscription names up to a specified length. We could then specify
> that any subscription name generated by a RA or EJB container must be shorter than this.
>
> The choice of a length is somewhat arbitrary, but how about requiring that a JMS provider must be able to handle
> subscription names of up to 128 characters? (It needs to be long enough to allow reasonably meaningful names to be
> generated from application name, MDB name, cluster name etc combined with some kind of hash to ensure that they are
> unique).
>
> Again this would not prevent JMS providers from supporting names longer than this. This is just defining a length which
> is guaranteed to be supported.
I haven't received any objections to this so I've now drafted the necessary changes.
I think this is an important feature as it allows applications, resource adapters and application servers to generate
subscription names with the certainty that they would be valid in any JMS provider.
If you know of any JMS provider which does not already satisfy this proposed requirement (or which could not be enhanced
to satisfy it) then please do let me know.
In the spec, I've added a new section:
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6.11.5. "Subscription name characters and length"
The JMS provider must allow a durable or non-durable subscription name to contain the following characters:
• Java letters
• Java digits
• Underscore (_)
• Dot (.)
• Minus (-)
JMS providers may support additional characters to these, but applications which use them may not be portable.
The JMS provider must allow a durable or non-durable subscription name to have up to 128 characters.
JMS providers may support names longer than this, but applications which use longer names may not be portable.
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In addition I have added an entry to the change history in appendix 5, since this is an important requirement which I
don't want people to miss.
You can read both sections in the draft spec:
http://java.net/projects/jms-spec/sources/repository/content/jms2.0/specification/word/JMS20.pdf
Nigel