Re: [paho-dev] Paho Java Client Exceptions

[Mike Tran <miketran@xxxxxxxxxx>]

Hi Dave,

By design, if the Java client is not
connected and the application attempts to publish or subscribe, MqttException
is thrown with reason code = REASON_CODE_CLIENT_NOT_CONNECTED 

https://www.eclipse.org/paho/files/javadoc/org/eclipse/paho/client/mqttv3/MqttException.html#REASON_CODE_CLIENT_NOT_CONNECTED

As for the retain flag, the MQTT specification
states that the Server (not the client) must store the application message:

http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718038

--
Regards,
Mike Tran




From:      
 Dave Jensen <david@xxxxxxxxxxxx>
To:      
 paho-dev@xxxxxxxxxxx
Date:      
 07/14/2015 02:44 AM
Subject:    
   [paho-dev] Paho
Java Client Exceptions
Sent by:    
   paho-dev-bounces@xxxxxxxxxxx

---

After using MQTT.js on the node.js platform I though it
would be simple to use MQTT with Java, on Android, using the Paho Java
client. I was wrong.

I've worked through most of my issues but there is one
that bothers me. My understanding is that when you retain messages and
publish, the client will figure out when to send. So if the connection
is down, the developer of the client keeps publishing and when the connection
is restored, the client goes ahead and publishes the messages. 

Using mqtt.js on node, I've testing this connection up,
pub, received, connection down, pub, nothing, pub again, nothing, connection
up, received both messages.

So when I tried a similar approach with the Paho Java
client, I remove the connection, publish, and bam, I get an exception.
Not only that, it also appears that the message is not retained in this
code path. This forces the client user to self retain that message.

Is this intentional? A bug? Is there a different API that
I should be using that I'm missing?

Any opinions, help, or criticisms would be greatly appreciated.

Thanks!
Dave_______________________________________________
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