Spring Integration TCP adapters

[Invincible]

Hi,

My requirement is to send a XML over TCP to a non spring component. I need to send messages very often. I was looking into Spring Integration TCP adapters and gateways as a solution. Is it mandatory to receive a response when a message is posted? In my scenario, I never get a response back.

Thanks,
Jan.

[Gary Russell]

No; an outbound channel adapter is "one way".

If you do, occasionally, get a response you can add an inbound channel adapter (using the same connection factory).

Gateways are request/reply based.

[Invincible]

Thanks Gary.

So, I am already using input-output channels in my application. Basically, I do some process and I sent out the result to an output channel. If there were any errors, I need to capture that and send it as an xml to a different application through TCP. Can I configure a TCP outbound channel adapter as a error channel?

Thanks,
Jan.

[Gary Russell]

Can you post your configuration? What is the entry point to your flow? Normally, for error handling, you declare an error-channel on the endpoint that starts your flow. If an error occurs upstream (and you use direct channels all the way), the exception is caught in the inbound endpoint and an ErrrorMessage is sent to the error-channel.

The ErrorMessage has a payload of type MessagingException, which has two properties

* cause - the original exception
* failedMessage - the message that was being processed when the exception occurred.

You can do whatever you want on the error channel, including adding a transformer to create the XML format you want, and sending it over TCP.

Hope that helps.

[Invincible]

My configuration is something like this:

<int:channel id="inputChannel">
<int:dispatcher task-executor="executor" />
</int:channel>

<task:executor id="executor"
pool-size="30"
queue-capacity="10000"
rejection-policy="CALLER_RUNS" />

<int:channel id="outputChannel">
<int:queue/>
</int:channel>

<int:service-activator input-channel="inputChannel"
output-channel="outputChannel"
ref="doSomeService"
method="service">
</int:service-activator>

<int:gateway id="serviceGateway"
service-interface="serviceGateway"
default-request-channel="inputChannel"
default-reply-channel="outputChannel" />

[Gary Russell]

Please use [ code ] ... [ /code ] tags (no spaces inside brackets) around code and config; it makes it easier to read.

So, just add an error channel to your gateway...

<int:gateway id="serviceGateway"
    service-interface="serviceGateway"
    default-request-channel="inputChannel"
    default-reply-channel="outputChannel" 
    error-channel="errorChannel"/> 

<int:channel errorChannel />

<int:transformer ref="someBeanToTransformExceptionToXML"
    input-channel="errorChannel" output-channel="toTCP" />

<int:channel id="toTCP" />

<int-ip:tcp-outbound-channel-adapter input-channel="toTCP" connectionFactory= ... />

Unless you have specific reasons for the explicit <dispatcher/> and <queue/> elements, I would suggest you remove them.

That way everything happens on the caller's thread and, if there is an exception sending to TCP, that exception will be thrown to the caller.