On 10/01/2012 12:37, Nigel Deakin wrote:
> I can't see any merit in returning a Set. What would we expect applications to use it for, other than call the
> iterator() method? (Though given that a Set is unordered, would an application really want to be able to fetch
> messages from a queue in a random order?)
>
> Aside from the major issue of memory usage and performance, methods like contains() couldn't be used portably since
> the JMS spec doesn't define how equals() behaves. (If applications really want to search through the queue for
> specific messages they can supply a message selector when they create the queue browser).
>
> I agree that Enumeration has been superseded by Iterator, but Enumeration is definitely not deprecated and the
> difference is small. I might argue that since Iterator defines a remove() method which we would not support then this
> might actually be confusing.
>
> But perhaps we should as part of a more general review we might have of the browsing and monitoring features of JMS
> rather than on its own. For
I missed out some words there. I meant to type "perhaps we should consider this as part of a more general review we
might have of the browsing and monitoring features of JMS rather than on its own"
Nigel
> example, do we need to allow durable subscriptions to be browsed? Do we need to add additional methods to allow the
> state of the queues and topics to be queried? This is something we might want to revisit after the Early Draft.
>
> Nigel
>
>
> On 09/01/2012 22:31, John D. Ament wrote:
>> Rudiger
>>
>> The ideal case would be the foreach styled loop.
>>
>> John
>>
>> On Mon, Jan 9, 2012 at 3:26 PM, Rüdiger zu Dohna <ruediger.dohna_at_1und1.de <mailto:ruediger.dohna_at_1und1.de>> wrote:
>>
>> @John: You can't do much with that Set than iterate over it, can you? Maybe even calculating the size could be
>> expensive.
>> @Nigel: Enumerations are just somewhat old fashioned and more ore less deprecated. If it was an Iterable
>> (contradicting myself), you could use it for an enhanced for-loop.
>>
>>
>> On 2012-01-09, at 19:45, John D. Ament wrote:
>>> I don't see much of a reason to not use a Set, since it should be unique. It could be a custom implementation
>>> that buffers the messages from the server.
>>>
>>> Just feels more modern to work with a clean collection rather than an enumeration.
>>>
>>> John
>>>
>>> On Mon, Jan 9, 2012 at 1:39 PM, Nigel Deakin <nigel.deakin_at_oracle.com <mailto:nigel.deakin_at_oracle.com>> wrote:
>>>
>>> Given that a QueueBrowser already provides a method to return an Enumeration, what would be the benefit in
>>> additionally returning a Iterator (unless we wanted to add support for remove())?
>>>
>>> Nigel
>>>
>>>
>>> On 09/01/2012 16:32, Rüdiger zu Dohna wrote:
>>>> Maybe it should return an Iterator<Message>? ... deliberately not an Iterable! This would make it clear
>>>> that it's just a snapshot and there's no much use to pass it as a collection around.
>>>>
>>>>
>>>> On 2012-01-09, at 15:01, Nigel Deakin wrote:
>>>>
>>>>> John,
>>>>>
>>>>> Simply returning a Set isn't very scalable: a queue might contain thousands (or hundreds of thousands) of
>>>>> messages. That's why the existing API returns an Enumeration.
>>>>>
>>>>> (Also, since a Queue is by definition ordered, returning a Set would be throwing away important semantics)
>>>>>
>>>>> Nigel
>>>>>
>>>>> On 09/01/2012 13:40, John D. Ament wrote:
>>>>>> Hi Nigel,
>>>>>>
>>>>>> No, I would leave the existing method, and add a new one:
>>>>>>
>>>>>> public Set<Message> getMessages() throws JMSRuntimeException { }
>>>>>>
>>>>>> I think Set is most appropriate, since the messages should be unique.
>>>>>>
>>>>>> On Mon, Jan 9, 2012 at 7:06 AM, Nigel Deakin <nigel.deakin_at_oracle.com <mailto:nigel.deakin_at_oracle.com>>
>>>>>> wrote:
>>>>>>
>>>>>> John,
>>>>>>
>>>>>>
>>>>>> On 06/01/2012 10:49, John D. Ament wrote:
>>>>>>
>>>>>> It may be a bit late, but is it possible for us to provide a set or list back that is properly
>>>>>> typed (e.g.
>>>>>> javax.jms.Message) from QueueBrowser?
>>>>>>
>>>>>>
>>>>>> Can you be more specific about what you are asking for?
>>>>>>
>>>>>> Are you asking for the existing method
>>>>>> Enumeration getEnumeration() throws JMSException;
>>>>>> to be changed to
>>>>>> Enumeration <Message> getEnumeration() throws JMSException;
>>>>>>
>>>>>> or something else?
>>>>>>
>>>>>> Nigel
>>>>>>
>>>>>>
>>>>
>>>
>>
>>