Questions on JBoss Messaging 1.4

[unwavering]

Dear all,
I have some questions:

Q1: How can I override the message header fields from JBoss Messaging 1.4? The reason is that I don't want the clients to control the message expiry and priority information.

Q2: What's the complete scenario which will cause a message to be moved to the DLQ? Does this happen when the consumer fails to process the message and sends a special acknowledgment as a result?

Q3: If I configure the server to set the expiration time to any message to infinity (no expiration), do I still need to have a default expiry queue?

Q4: Is moving a message to a DLQ dependent only on the consumer response? In other words, is there any scenario which will cause the server to move a message to a DLQ without the consumer's intervention?

Thanks a lot for your time.

[gaohoward]

Q1 : you can have a look at JBossMessage class.

Q2 : If a message is failed to be delivered by JBM for a certain times, it will go to DLQ if specified.

Q3 : no. I don't think you need it if your messages never expire.

Q4 : see Q2 for reference.

[unwavering]

Thanks gaohoward. I still need some explanations:

Q1: Is there a configurable way to define default message headers from JBoss?

Q2: How do you define 'delivery'? Is it delivery between internal components of JBoss? Or is it delivery between external clients and JBoss?

[gaohoward]

Q1: Is there a configurable way to define default message headers from JBoss?

--- I don't think it has a way to configure default values for message headers.

Q2: How do you define 'delivery'? Is it delivery between internal components of JBoss? Or is it delivery between external clients and JBoss?

-- here the delivery means the process in which messages are sent from JBM server to the clients (consumers).

[timfox]

"gaohoward" wrote:
Q1: Is there a configurable way to define default message headers from JBoss?

--- I don't think it has a way to configure default values for message headers.

Actually you can probably do this by providing an AOP interceptor in JBM 1.x.

In JBM 2.0 interceptors are fully supported, see the docs for more info.

[unwavering]

Another question:

I'm using a JMS client to drop messages in JBM 1.4. Although the client is changing the message header properties (expiry and priority), these changes are not taking effects on JBM. For example, the client is setting the message expiry to 1 second but JBM is keeping the message forever in the destination queue without moving it to the expiry queue. Can you help me to understand the reasons?

Thanks all.

[gaohoward]

Hi, I think about those values you should consult JMS spec. Some of them are determined only when the message is sent. for example in the spec

JMSPriority
The JMSPriority header field contains the message’s priority.
When a message is sent, this field is ignored. After completion of the send, it
holds the value specified by the method sending the message.

That means you need to specify the priority in send() method.

[unwavering]

You're right gaohoward. The priority should be set at the method level (send method) rather than at the message level. But I still can't control the expiry of the message even from the send() method. I will review the specs as you suggested. Thanks.