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From Rajith Attapattu <rajit...@gmail.com>
Subject Re: messaging::Message API documentation
Date Wed, 16 Mar 2011 16:36:07 GMT
On Wed, Mar 16, 2011 at 11:50 AM, Carl Trieloff <cctrieloff@redhat.com>wrote:

>
>  1.      Can you tell by calling getContentType whether to call getContent
>> or getContentPtr or getProperties, or does that
>> require the sender to set the content type?  Is there a convention or is
>> there a helping class like possibly Variant?
>>
>
> In most cases it requires the sender to set it. If you are using mapped
> message, I believe we set it
>
>
The content type should be set by the client lib for text, list and map
messages across JMS, Python,  C++ (and the swig clients off the C++ clients)
with the following exceptions.
map - amqp/map
text - text/plain - for c++ the sender needs to explicitly set it.
list - amqp/list  (The JMS client has no direct support for list messages)

if no content type is specified, all clients will treat the payload as
binary.
The JMS client has explicit support for binary via
"application/octet-stream".

Anything else the application will need to explicitly specify the content
type and handle them accordingly at the application level.


>
>
>> 3.      By setting TTL, Durable, Redelivered, what behavior does the
>> system exhibit?
>>
>
> TTL, will cause the message to be dequeued and discarded if the TTL has
> been reached.
>
> Durable will cause the message to be written to disk, if the queue it is
> being routed to is marked as durable.
>
> Redelivered is set when a consumer read a message, and then rejects it. The
> flag is an indication that the
> message delivery is being re-attempted for the next consumer trying to
> consume it
>
>
Redelivered will also be set if a message was delivered to a client but who
has not had time to ack it due to,
1) Broker failover
2) Client error.

I am not sure if rejected messages are not redelivered. Alan can you please
confirm.
A bit later I will actually test this out and let you know.

>
>  4.       Does the broker modify any of the settings or are they only for
>> use by the broker? MessageId?
>>
>
> Application headers are not touched.
>
> Delivery headers may be updated, for example Sequence numbers can be
> inserted, or we also insert tags for
> federation etc.
>
> MessageID is a client set property.
>
>
>  5.      Are there any conventions that should be followed for string data
>> in this class that are used in other AMQP systems or language versions of
>> Apid?
>>
>>
>
binary, text and map data is supported across all clients.
there is no direct support for list messages in JMS -  you can however
insert a list inside a map message :)

>
> If you want cross client data interop, take a look at mapped message.
>
>
>
>  Thanks,
>>
>> Dave
>>
>> David Hickerson
>>   david.a.hickerson@boeing.com<mailto:david.a.hickerson@boeing.com>
>> Senior Engineer
>>    phone: <719-235-3265>719-235-3265
>> Mission Operations
>> The Boeing Company
>> 1330 Inverness Dr., Suite 330
>> Colorado Springs, CO 80910
>>
>>
>>
>>
>
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> Apache Qpid - AMQP Messaging Implementation
> Project:      http://qpid.apache.org
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>
>

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