Cannot use viewAccepted in RecieverAdapter while using ForkChannel to leverage exisiting Infinispan JGroups Channel

[Jikku Joyce]

Hi,

I am using fork channel api to fork my main channel. I have set it as a receiver using my implementation of reciever adapter. I can send and receive messages but cannot use the inherited method "viewAccepted" which should theoretically get invoked when there is a change in the jgroups view. But I do not get control to this method when I add a node or remove a node. However I still get control at my main channel's infinispan listerner class implementation annotated by @ViewChanged. This makes me confused.

1. Is this the expected behavior?
2. The fork channel does not send messages via the main channel. Is this understanding right?
3. When a node in main channel goes down or a new node is added, the fork channel also behaves similar to main channel. Is this right?
4. Is there a way to convert Infinispan Address to JGroups Address?

[Bela Ban]

On 25.03.19 13:17, Jikku Joyce wrote:

Hi,

I am using fork channel api to fork my main channel. I have set it as a
receiver using my implementation of reciever adapter. I can send and
receive messages but cannot use the inherited method "viewAccepted"
which should theoretically get invoked when there is a change in the
jgroups view.

Take a look at the program below. I set a ReceiverAdapter and implement
viewAccepted(), which is called.

But I do not get control to this method when I add a node
or remove a node. However I still get control at my main channel's
infinispan listerner class implementation annotated by @ViewChanged.
This makes me confused.

1. Is this the expected behavior?
2. The fork channel does not send messages via the main channel. Is
   this understanding right?

No. A ForkChannel is depending on the main channel, and its lifecycle is
a subset of the main channel's lifecycle.

1. When a node in main channel goes down or a new node is added, the
   fork channel also behaves similar to main channel. Is this right?

Yes

1. Is there a way to convert Infinispan Address to JGroups Address?

I suggest look at how the InfinispanAddress is implemented. I assume
this is possible; for example JGroupsAddress has a getJGroupsAddress()
method.

public class bla4 {
protected JChannel ch;
protected ForkChannel fc1, fc2;

 protected void start() throws Exception {
     ch=new JChannel("/home/bela/fork.xml");
     fc1=new ForkChannel(ch, "counter", "fc1");
     fc2=new ForkChannel(ch, "lock", "fc2");

     fc1.setReceiver(new ReceiverAdapter() {
         public void viewAccepted(View view) {
             System.out.printf("%s: view is %s\n", fc1.getAddress(),

view);
}
});
fc2.setReceiver(new ReceiverAdapter() {
public void viewAccepted(View view) {
System.out.printf("%s: view is %s\n", fc2.getAddress(),
view);
}
});

     ch.connect("demo");
     fc1.connect("bla");
     fc2.connect("foo");
 }

 public static void main(String[] args) throws Exception {
     new bla4().start();
 }

}

---

Cannot use viewAccepted in RecieverAdapter while using ForkChannel to
leverage exisiting Infinispan JGroups Channel
https://sourceforge.net/p/javagroups/discussion/18794/thread/9bccf3e2b2/?limit=25#9937

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--
Bela Ban | http://www.jgroups.org

[Jikku Joyce]

Hi Bela,

Thanks for the reply.

I created ForkedChannel as below:

public ReceiverAdapterImpl() { //Constructor of my receiver adapter implementation
jGroupsTransport = ispnCache.getAdvancedCache().getRpcManager().getTransport();
jGroupsMainChannel = ((JGroupsTransport)jGroupsTransport).getChannel();
jGroupsForkChannel = new ForkChannel(jGroupsMainChannel,
                    "stackId",
                    "channelId",
                    true, ProtocolStack.Position.ABOVE, TCP.class); jGroupsForkChannel.connect("comms");
jGroupsForkChannel.setReceiver(this);
}

But when a new node was added to the cluster I did not get control to my viewAccepted() method in my ReceiverAdapter. I do not have control over infinispan channel creation, so I cannot call my mainChannel.connect() after I create forkChannel. Is this the problem?

I get call back in my infinispan listener class to its @VIewChanged annotated method though.

[Bela Ban]

You main mistake was to add FORK just above the transport (TCP).
Instead, FORK needs to be placed at the top of the protocol stack:

public class bla4 extends ReceiverAdapter {
protected JChannel ch;

 protected void start() throws Exception {
     ch=new JChannel(); // uses udp.xml by default
     TP transport=ch.getProtocolStack().getTransport();
     transport.setBindAddress(Util.getLocalhost());
     ch.connect("demo");
     ForkChannel jGroupsForkChannel=new ForkChannel(ch,
                                                    "stackId",
                                                    "channelId",
                                                    true,

ProtocolStack.Position.ABOVE, FRAG2.class);
jGroupsForkChannel.setReceiver(this);
jGroupsForkChannel.connect("comms");
System.out.printf("-- %s started, waiting for messages\n",
jGroupsForkChannel.getAddress());
}

 public void viewAccepted(View view) {
     System.out.println("view = " + view);
 }

 public static void main(String[] args) throws Exception {
     new bla4().start();
 }

}

On 26.03.19 14:09, Jikku Joyce wrote:

Hi Bela,

Thanks for the reply.

I created ForkedChannel as below:

public ReceiverAdapterImpl() { //Constructor of my receiver adapter implementation
jGroupsTransport = ispnCache.getAdvancedCache().getRpcManager().getTransport();
jGroupsMainChannel = ((JGroupsTransport)jGroupsTransport).getChannel();
jGroupsForkChannel = new ForkChannel(jGroupsMainChannel,
"stackId",
"channelId",
true, ProtocolStack.Position.ABOVE, TCP.class); jGroupsForkChannel.connect("comms");
jGroupsForkChannel.setReceiver(this);
}

But when a new node was added to the cluster I did not get control to my
viewAccepted() method in my ReceiverAdapter. I do not have control over
infinispan channel creation, so I cannot call my mainChannel.connect()
after I create forkChannel. Is this the problem?

I get call back in my infinispan listener class to its @VIewChanged
annotated method though.

---

Cannot use viewAccepted in RecieverAdapter while using ForkChannel to
leverage exisiting Infinispan JGroups Channel
https://sourceforge.net/p/javagroups/discussion/18794/thread/9bccf3e2b2/?limit=25#9937/598a/9dd3

---

Sent from sourceforge.net because you indicated interest in
https://sourceforge.net/p/javagroups/discussion/18794/

To unsubscribe from further messages, please visit
https://sourceforge.net/auth/subscriptions/

--
Bela Ban | http://www.jgroups.org

[Jikku Joyce]

Hi Bela,

I tried with FRAG2 initially. But I was not able to create fork channel and was getting a null pointer exception as below:

java.lang.NullPointerException
    at org.jgroups.stack.ProtocolStack.insertProtocol(ProtocolStack.java:603)
    at org.jgroups.fork.ForkChannel.getFORK(ForkChannel.java:281)
    at org.jgroups.fork.ForkChannel.<init>(ForkChannel.java:75)

Then only when I used TCP.class I was able to get it working. Any idea why this happens?

When I analyse my main channel :
my bottom protocol is TCP,
down protocol is STATE_TRANSFER,
top protocol is STATE_TRANSFER and
up protocol is null.

Can you share your JGroups configuration too?

[Bela Ban]

Well, FRAG2 is not in your stack. Try STATE_TRANSFER instead.
You cannot place FORK directly above the transport, it needs to be at the top of the stack!

[Jikku Joyce]

That worked Bela !!! Thanks a lot for the help.