Transform + Divert usage question

[shergill]

I was looking forward to using a divert on HornetQ to divert messages on a given address to many other addresses. What I would like to do is add some additional properties on the message ONCE it gets diverted. It seems like I can use a transformer class to do just that. My only question is that I would like to add custom properties based on the divert that the message came on. I am not sure how to get that info.

Example: address.order -> divert it to address.electronicorder, address.bookorder, address.clothorder.

Now once it gets diverted; I would like to add a property (like "ORDER TYPE") on the message in the transformer.. but I am not sure how I can get the divert that the message came on..

Any tips?

[clebert.suconic]

It seems like you need multiple Diverts and one Transformer per target address?

[jdahlbom]

Clebert has it right, below is my implementation:

AbstractTransformer

import org.hornetq.core.server.ServerMessage;

import org.hornetq.core.server.cluster.Transformer;

public abstract class AbstractTransformer implements Transformer {

    protected abstract String getMessageType();

    @Override

    public ServerMessage transform(ServerMessage message) {

        message.putStringProperty(TransformationConstants.IDENTIFYING_PARAMETER, getMessageType());

        return message;

    }

}

RequestEmailTransformer:

public class RequestEmailTransformer extends AbstractTransformer {

    @Override

    protected String getMessageType() {

        return TransformationConstants.TYPE_REQUEST_EMAIL;

    }

}

TransformationConstants:

public final class TransformationConstants {

    public static final String IDENTIFYING_PARAMETER = "messageType";

    public static final String TYPE_REQUEST_EMAIL = "requestEmail";

}

I bundle all the transformers into a jar and deploy that separately.

hornetq-configuration.xml on the sending side of the bridge, which also applies the transformations:

   <diverts>

        <divert name="email-divert">

                <address>jms.queue.requestEmail</address>

                <forwarding-address>jms.queue.storeAndForward</forwarding-address>

                <transformer-class-name>

                        my.package.RequestEmailTransformer

                </transformer-class-name>

                <exclusive>true</exclusive>

        </divert>

  </diverts>

hornetq-configuration.xml on the receiving side of the bridge (in jboss 6.1):

   <diverts>

        <divert name="email-divert">

                <address>jms.queue.receiverQueue</address>

                <forwarding-address>jms.queue.requestEmail</forwarding-address>

                <filter string="messageType='requestEmail'"/>

                <exclusive>true</exclusive>

        </divert>

   </diverts>

EDIT: Added diverts with transformations.

[shergill]

Where are you specifying the transform? I dont see it in your divert configuration. If you were to do it there; do you use the 'Abstract Transformer'?

[shergill]

My other option is to rebuild HornetQ from source and add this line in the DivertBindings.java

   public void route(final ServerMessage message, final RoutingContext context) throws Exception

   {

      // add this line

      message.setProperty("DIVERTNAME", routingName);

      divert.route(message, context);

   }

[jdahlbom]

Oops, looks like I pasted the wrong end of the bridge configuration.

Below is the correct one - also added to my original reply.

hornetq-configuration.xml on the sending side of the bridge, which also applies the transformations:

   <diverts>

        <divert name="email-divert">

                <address>jms.queue.requestEmail</address>

                <forwarding-address>jms.queue.storeAndForward</forwarding-address>

                <transformer-class-name>

                        my.package.RequestEmailTransformer

                </transformer-class-name>

                <exclusive>true</exclusive>

        </divert>

  </diverts>

AbstractTransformer is not directly used anywhere (obviously, it being abstract), it merely exists to avoid duplicating attribute adding code in my several near-identical transformers (one for every queue).

Adding your own diverts to HornetQ binaries is wrong, not to mention unmaintainable.

[shergill]

Can someone tell me if there is a problem with doing what i'm doing here.

I've made this change in the 2.2.5 source (from SVN) and compiled a build. It does exactly what I wanted to do.. but I would like to get some feedback from the developers if this is ok or not.

The change is in 'DivertBinding.java'.

  public void route(final ServerMessage message, final RoutingContext context) throws Exception

   {

      message.putStringProperty(SimpleString.toSimpleString("ROUTINGNAME"), getRoutingName());

      divert.route(message, context);

   }