Develop Reference

spring integration callback on message received

Still new to spring and spring integration so please bear with me. =)
I have set up a client to connect to a remote server using TCP. The server sends a message as soon as a connection is established. Using ngrep I have verified that the connection is up and that the message is sent from the server.
By using the gateway interface "gw" I can successfully receive the message. However what I would like to do is to trigger the com.example.Client.onMessage method when a message is received. My understanding is that this should be possible using a ServiceActivator as shown below. Is this true or do I have to use my own dedicated thread doing a blocking receive? Thanks.
Configuration
<bean id="javaDeserializer"
class="org.springframework.integration.ip.tcp.serializer.ByteArrayLfSerializer" />
<int-ip:tcp-connection-factory id="client"
type="client" host="localhost" port="12000"
single-use="false" so-timeout="10000" so-keep-alive="true" deserializer="javaDeserializer"
serializer="javaSerializer"/>
<int:gateway id="gw" service-interface="com.example.Interface"
default-request-channel="input" default-reply-channel="replies" />
<int:channel id="input" />
<int:channel id="replies">
<int:queue />
</int:channel>
<int-ip:tcp-outbound-channel-adapter
id="outboundClient" channel="input" connection-factory="client" />
<int-ip:tcp-inbound-channel-adapter
id="inboundClient" channel="replies" connection-factory="client"
client-mode="true" retry-interval="10000" auto-startup="true" />
<int:service-activator input-channel="input" output-channel="replies" ref="com.example.Client" method="onMessage" />
ServiceActivator
#EnableIntegration
#IntegrationComponentScan
#MessageEndpoint
public class Client {
#ServiceActivator
public void onMessage(byte[] received) {
//Not called
}
}

#EnableIntegration and #IntegrationComponentScan must be configured on the #Configuration. The general Spring annotations configuration principles: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/beans.html#beans-java. Although having an XML config you don't need those annotations at all.
If you want to receive messages from TCP to the <service-activator>, you have to configure its input-channel to the replies.
Right now you have a mess in your config: several subscribers for the input channel. In this case they receive incoming messages via round-robin manner.
If I understand correctly you should remove all the <int:gateway> staff and just perform step #2. Although it isn't clear how you are going to send messages to the input channel...

How to alter MQ headers using Spring JmsTemplate

I'm using simple Spring JmsTemplate to send messages onto a MQ.
<beans:bean id="myJMSTemplate" class="org.springframework.jms.core.JmsTemplate">
<beans:property name="connectionFactory">
<beans:ref bean="cachedConnectionFactory" />
</beans:property>
<beans:property name="pubSubDomain">
<beans:value>false</beans:value>
</beans:property>
<beans:property name="receiveTimeout">
<beans:value>1000</beans:value>
</beans:property>
</beans:bean>
<int-jms:outbound-channel-adapter id="sendMessageToAvengers" channel="antEventChannel" jms-template="myJMSTemplate" destination-name='com.marvel.avengers.antMan'/>
This works fine, however, My client application isn't able to process the message as the message format is in 'MQHRF2' by default.
How can I alter my MQ headers so as to send explicitly MQSTR format.
Thanks in advance.

You must set the property targetcllient=1 to send the msg as MQSTR.
To do this in sending part of java code, change the queue name as below
String senderQ = "queue:///MYQUEUENAME?targetClient=1";
jmsTemplate.send(senderQ, new MessageCreator() {
public Message createMessage(Session session) throws JMSException {
TextMessage message = session.createTextMessage(text);
message.setJMSReplyTo(replyToQ);
return message;
}
});
Alternatively you can try setting this in jmstemplate bean
<bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
<!-- set format to MQSTR with "targetClient=1" parameter -->
<property name="defaultDestinationName" value="queue:///default?targetClient=1" />
<property name="connectionFactory" ref="mqConnectionFactory" />
</bean>

The IBM MQ JMS interface has a property called TARGCLIENT which when set to the value MQ will not add the MQRFH2 header. I don't know whether the Spring interface allows it to be used.
Alternatively, the queue definition on the queue manager can be configured to remove the header for those applications that can't process it. This is a better way to remove the MQRFH2 header as it removes it at get time instead of at put time, thus meaning that if an application is able to process the MQRFH2 header, it is still there, but for those applications that cannot process it, it is removed for them.
To make the queue operate in this way, issue the following MQSC command on your queue manager:
ALTER QLOCAL(q-name) PROPCTL(NONE)
Additional Reading
Properties of IBM MQ classes for JMS objects > TARGCLIENT
PROPCTL queue options
DEFINE queues - see PROPCTL attribute

http request - camel's concurrency

Does any method of camel's consumer exist which is able to process >20 http requests per second? I try to work with restlet and jetty components, but failed with both.
For example, I set this config for a jetty component:
<bean id="jetty" class="org.apache.camel.component.jetty.JettyHttpComponent">
<property name="httpClientMinThreads" value="10"/>
<property name="httpClientMaxThreads" value="254" />
<property name="minThreads" value="10"/>
<property name="maxThreads" value="254" />
</bean>
and hoped that everything will be OK, but nothing.
My route config:
from("jetty:http://0.0.0.0:8888" + linkRequest+"?matchOnUriPrefix=true")
.onException(Exception.class)
.log(LoggingLevel.ERROR, "${exception.stacktrace}")
.useOriginalMessage()
.handled(true)
.setBody(simple("Something went wrong"))
.end()
.process(new MyFirstProcessor())//here I get httpHeaders,create entity A
.to("jpa:RequestEntity")
.process(new MySecondProcessor())//set some filed in entity A and send it
.to("bean:service?method=process")//here I recieve entity A and create entity B
.to("jpa:ResponseEntity")
.process(new MyThirdProcessor())//here response is created;
Please explain to me how I can configurate parameters of camel (I glance at the threading model configuration), jetty-component or restlet component - so that my router can handle all incoming requests.
UPDATE
These problems were caused by the settings of the connection pool to the database.

jms error handler: receive a callback only when jms gives up

I am using spring-jms with active mq.
I have a ErrorHandler listener set up, that receives a callback each time a jms message delivery fails - i.e. the method that processes the message throws an exception instead of returning gracefully.
However my jms is configured to retry several times until the jms delivery finally succeeds. And my callback is notified of all of the failures.
What I want is a listener that receives a notification only when all the retries finally fail. The motivation is to bring the issue up for the admin's attention. But I don't want spurious notifications in the admin's console.
<bean abstract="true" id="abstractDestinationListener"
class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="connectionFactory" ref="jmsFactory" />
<property name="errorHandler" ref="destinationErrorHandler"/>
<property name="sessionTransacted" value="true"/>
</bean>

What you might consider is using a per-destination dead-letter queue (individualDeadLetterStrategy - https://activemq.apache.org/message-redelivery-and-dlq-handling.html) for the destinations in question. When the maximum redelivery count has been hit, the message is moved out to the DLQ. You can then set up a consumer on that queue with a listener that emails the administrator.
Another way to do it might be to wrap your listener with a try-catch, and rethrow any exceptions only if message.getIntProperty("JMSXDeliveryCount") < MAX_REDELIVERY_COUNT, and email the admin otherwise. However, that option means placing your redelivery limit in two places - the broker config and the code.

if you need more fine-grained control/flexibility/routing with JMS messaging/handling, then you should just use Apache Camel's error handling...

Activemq how to configure a consumer listener (in Java)

I would be happy on the condition that anyone share a simple sample for xml based configuration of consumer listener in Spring. Thanks in advance.
EDIT;
I just would like to hear about the listener of consumer, not the consumer implementation because I have already implemented an active-mq in my app. and it is running well, however I cannot be sure the order of consuming items which are send by producer synchronously.
The problem is the inconsistency and data manipulation due to async executions of a method (persisting some objects to db in order to log them) from concurrent consumers at a time.
EDIT2:
Let me clarify this complexity. I have an application that consist of two base separate parts. The first one is the synchronously executing Producer that asks db for the products newly come, and then "one by one" send them thorough the "jmsTemplate.send" method provided by active-mq. This was the operation which is synchronously executed from a Cron/Timer. In other words, producer is being executed from a timer/cron. Now The problem is consumer itself. When producer sends products "one by one", async consumers (with concurrency enabled) receive the products and consume them asynchronously.
The problem begins here. Because the method, which is executed from the consumer when the products are just received, does some db persistence operations. When the same product is being received by separate concurrent consumers (it happens because of our system, not a jms issue, dont pay attention on this point) then doing the same persistence operations on the same entity occurs some exceptions as easy to predict. How can I prevent this async operations of products or manage the orders of comsuming products in that kind of application.
Thanks.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jms="http://www.springframework.org/schema/jms"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/jms http://www.springframework.org/schema/jms/spring-jms-3.0.xsd">
<!-- A simple and usual connection to activeMQ -->
<bean id="activeMQConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
<property name="brokerURL" value="tcp://localhost:61616"></property>
</bean>
<!-- A POJO that implements the JMS message listener -->
<bean id="simpleMessageListener" class="MyJMSMessageListener" />
<!-- Cached Connection Factory to wrap the ActiveMQ connetion -->
<bean id="cachedConnectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
<property name="targetConnectionFactory" ref="activeMQConnectionFactory"></property>
<property name="sessionCacheSize" value="10"></property>
<property name="reconnectOnException" value="true"></property>
</bean>
<!-- The Spring message listener container configuration -->
<jms:listener-container container-type="default" connection-factory="cachedConnectionFactory" acknowledge="auto">
<jms:listener destination="FOO.TEST" ref="simpleMessageListener" method="onMessage" />
</jms:listener-container>
</beans>
And the Java class that listens to the message itslef:
import javax.jms.Message;
import javax.jms.MessageListener;
public class MyJMSMessageListener implements MessageListener{
#Override
public void onMessage(Message message) {
// Do your work here
}
}
Starting this listener it's a matter of getting the Application Context, it will auto-start the JMS Listener once you do that.
EDIT according to the other question :
So your system may generate (for example) 2 or even more messages delivered to the Consumers with the same productID? Well first this is rather not YOUR problem, but the application's. Even if you somehow you fix it, it is not really a fix, but it is a way to hide the problem itself. Nevertheless, if forced to provide a solution, right now, I can think of only one, the easiest, disable the concurrent consuming, sort of. Here is what I would do: Receive the messages in the Queue and have only one Consumer on that queue. Inside this Consumer I would process as little from the message as I can - take ONLY the productID and place it in some other queue. Before this you would have to always check if the productID is not already in that queue. If it is just return silently, if it is not, that means it has never been processed, thus place this message in a different Queue : Queue2 for example, and then enable concurrent consumers on the second Queue Queue2. This still has flaws though: first the productID queue should somehow be cleaned once in a while, otherwise it will grow forever, but that is that that hard. The tricky part: what if you have a productID in the productID queue, but the product came for an UPDATE in the DB and not INSERT? You should not reject it then...