[rabbitmq-discuss] Exclusive Producers?

Mon Feb 24 14:10:34 GMT 2014

Hi,

@Alvaro, your solution seems to be quite interesting. I just wonder if 
there is a simpler one.

I have a similar problem where I need to start/stop the RabbitTemplate 
object on demand. For example to restart the bean in my catch block with 
sender.stop() and then sender.start() .

My first idea was to implement SmartLifeCycle interface from Spring and 
extend RabbitTemplate as follows.:

@Component
public class LifeSender extends RabbitTemplate implements SmartLifecycle {

private volatile boolean isRunning = false;

@Override
public boolean isAutoStartup() {
return true;
}

@Override
public void start() {
System.out.println("STARTED!!!");
isRunning = true;
}

@Override
public void stop() {
System.out.println("STOPPED!!!");
isRunning = false;
}

Here is the Spring AMQP context:

*<bean id="sender" 
class="org.springframework.amqp.rabbit.core.Rabbit Template" 
abstract="true"><constructor-arg index="0" ref="connectionFactory" 
/><property name="confirmCallback" ref="premCallback" /><property 
name="exchange" value="myExchange" /></bean>*

<bean id="lifeSender" class="com.ucware.ucpo.cti.core.LifeSender" 
parent="sender"/>

The problem is that lifeSender does not instatiate the properties and 
connection factory from the sender. So I created the constructor:

@Autowired
public LifeSender(ConnectionFactory connectionFactory, PremConfirmCallback 
premCallback) {
super();
super.setConnectionFactory(connectionFactory);
super.setExchange("cti.main");
super.setConfirmCallback(premCallback);
System.out.println(super.getConnectionFactory().to String());
}

Unfortunately, lifeSender.stop() does not do more than just printing 
"STOPPED" to the log. I am still able to send messages.

Second idea was to use controlChannel from Spring Integration. However, a 
simple test

@Test
public void testTurnOffSender() throws InterruptedException {
isBean = controlGateway.isRunning( "@sender.isRunning()" );

Assert.isTrue( isBean);
controlGateway.send(new GenericMessage<String>( "@sender.stop()" ));
Thread.sleep(500);
isBean = controlGateway.isRunning( "@sender.isRunning()" );
Assert.isTrue( isBean == false);

}

triggers the exception:

*org.springframework.expression.EvaluationException : The method 
'isRunning' is not supported by this command processor. If using the 
Control Bus, consider adding @ManagedOperation or @ManagedAttribute.*

Do you think any of suggested solutions make sense?

Thanks,
Lukasz

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