Camel and best practice of using POJO

[milanmilas]

Hi,

I've been playing with camel for a month and went from PAYLOAD to POJO format.

I want to use this one as objects I will be getting are going to be complex.

I still have questions and don't have clear picture how to use it.

When getting exchange from cxf:pojo I can use:

MessageContentsList msgList = (MessageContentsList)exchange.getIn().getBody();

Person person = (Person)msgList.get(0);

to get my Person object (class generated by plugin).

I am not sure now to push it to ActiveMQ, using xstream?

As well I am not sure how to deserialise object on another ESB where camel is reading from

ActiveMQ as I will need reference to Person class?

What if first ESB with ActiveMQ is third party project and in second ESB I am reading from

that ActiveMQ in Camel?

Is there a way in java to do Deserialisation/Unmarshaling without having reference to java class type?

[davsclaus]

Hi

Just a note you can get the person a bit quicker using

Person person = exchange.getIn().getBody(Person.class);

When you use CXF in POJO mode, you may have generated the source code from a wsdl file using wsdl2java. If so the generated code has JAXB annotations on the source code.

This allows you to automatic transform the POJO to/from XML using JAXB. So you do not need to use xstream etc.

So when you send the POJO to a JMS queue, then Camel will send the message depending on the type of the message body. So a POJO will be send as a javax.jms.ObjectMessage. But you want that as XML text instead, so you can either do:

Convert the message to XML before sending to JMS, eg

<route>
  ...
  <convertBodyTo type="String"></convertBodyTo>
  <to uri="activemq:queue:foo"></to>
</route>

Or you can configure the JMS/ActiveMQ endpoint with the type you want, using the jmsMessageType option eg

<route>
  ...
  <to uri="activemq:queue:foo?jmsMessageType=Text"></to>
</route>

[davsclaus]

Just a note, you would need to have camel-jaxb on the classpath. This is automatic installed if using Fuse ESB.

camel-jaxb allows Camel to seamless convert data from JAXB to/from XML.

[milanmilas]

using<convertBodyTo type="String"/>

-

---

        <log message="$"/>         <convertBodyTo type="String"/>         <log message="Converted body to string"/>         <inOnly uri="activemq:topic:Producer"/> -

---

org.apache.camel.InvalidPayloadException: No body available of type: java.lang.String but has value: of type: org.apache.cxf.message.MessageContentsList on: Message: . Caused by: No type converter available to convert from type: org.apache.cxf.message.MessageContentsList to the required type: java.lang.String with value . Exchange[Message: ]. Caused by: [org.apache.camel.NoTypeConversionAvailableException - No type converter available to convert from type: org.apache.cxf.message.MessageContentsList to the required type: java.lang.String with value ] org.apache.camel.InvalidPayloadException: No body available of type: java.lang.String but has value: of type: org.apache.cxf.message.MessageContentsList on: Message: . Caused by: No type converter available to convert from type: org.apache.cxf.message.MessageContentsList to the required type: java.lang.String with value . Exchange[Message: [com.all ocatesoftware.pocesb.Person@e38a55]]. Caused by: [org.apache.camel.NoTypeConversionAvailableException - No type converter available to convert from type: org.apache.cxf.message.MessageContentsList to the required type: java.lang.String with value ] using <inOnly uri="activemq:topic:Producer?jmsMessageType=Text"/> -

---

producer: <inOnly uri="activemq:topic:Producer?jmsMessageType=Text"/> consumer: <route id="consumerCxf">         <from uri="activemqconsumercxf:queue:Consumer?jmsMessageType=Text"/>         <log message="With Camel Headers"/>         <log message="$"/>         <log message="$"/>

-

---

There is no exception but body is null.

If I try to use:

I am getting error:

org.apache.camel.InvalidPayloadException: No body available of type: java.lang.String but has value: of type: org.apache.cxf.message.MessageContentsList on: Message: . Caused by: No type converter available to convert from type: org.apache.cxf.message.MessageContentsList to the required type: java.lang.String with value . Exchange[Message: ]. Caused by: [org.apache.camel.NoTypeConversionAvailableException - No type converter available to convert from type: org.apache.cxf.message.MessageContentsList to the required type: java.lang.String

I know body is MessageContentsList where first element i the list is Person but in every

example on internet only from().marshall() is used.

Is there example on the web where I can see how someone is pushing data to CXF with

POJO and after that to the Queue and back?

Edited by: milanmilas on Jan 14, 2013 10:58 AM

Edited by: milanmilas on Jan 14, 2013 10:59 AM

[milanmilas]

-

Edited by: milanmilas on Jan 15, 2013 10:35 AM

[milanmilas]

-

Edited by: milanmilas on Jan 15, 2013 10:44 AM

[davsclaus]

Hi

Ah yeah camel-cxf is unforuntaly using that internal MessageContextList that complicates things.

You can convert to the POJO class instead first

<convertBodyTo type="com.pocesb.Person"/>

Then the message contains the POJO class, and then you can convert that to a String afterwards. So you do 2x conversions.

<convertBodyTo type="String"/>

Though you can omit the String convertBodyTo, if you configure the JMS endpoint with jmsMessageType=Text, which tells Camel to force converting to String when sending the message to the JMS message queue.

[milanmilas]

First step works fine:

    jaxb prettyPrint="false" contextPath="com.pocesb"

    partClass="com.pocesb.Person"

    fragment="true"

    partNamespace="Person" />

Thanks for help, it took me too much time to understand all this.

Edited by: milanmilas on Jan 15, 2013 10:45 AM

Edited by: milanmilas on Jan 15, 2013 10:46 AM

Edited by: milanmilas on Jan 15, 2013 10:51 AM