Compatibility with JGroups 2.8

[brian.stansberry]

Hi,

One of the things I'd like to do for the upcoming AS 5.2 is move to JGroups 2.8. The big impediment to that has been that a number of projects (AS, JBC, JBM) have some code that casts JGroups Address objects from the Address interface used in the API to the IpAddress concrete class that JGroups has historically used. A big change in 2.8 is the Address type is no longer IpAddress.

The use of IpAddress in JBM 1.4.x is in the PostOfficeAddressInfo class, where the cast is done to allow serialization via the JGroups Streamable interface. There's a pretty easy fix for that though, as JGroups exposes a utility method that does what JBM currently does without requiring JBM to cast:

Index: src/main/org/jboss/messaging/core/impl/postoffice/PostOfficeAddressInfo.java
===================================================================
--- src/main/org/jboss/messaging/core/impl/postoffice/PostOfficeAddressInfo.java (revision 7825)
+++ src/main/org/jboss/messaging/core/impl/postoffice/PostOfficeAddressInfo.java (working copy)
@@ -27,7 +27,7 @@


 import org.jboss.messaging.util.Streamable;

 import org.jgroups.Address;

-import org.jgroups.stack.IpAddress;

+import org.jgroups.util.Util;



 /**

 *

@@ -70,30 +70,16 @@


 public void read(DataInputStream in) throws Exception

 {

- controlChannelAddress = new IpAddress();

-

- controlChannelAddress.readFrom(in);

-

- dataChannelAddress = new IpAddress();

+ controlChannelAddress = Util.readAddress(in);



- dataChannelAddress.readFrom(in);

+ dataChannelAddress = Util.readAddress(in);

 }



 public void write(DataOutputStream out) throws Exception

 {

- if (!(controlChannelAddress instanceof IpAddress))

- {

- throw new IllegalStateException("Address must be IpAddress");

- }

-

- if (!(dataChannelAddress instanceof IpAddress))

- {

- throw new IllegalStateException("Address must be IpAddress");

- }

+ Util.writeAddress(controlChannelAddress, out);



- controlChannelAddress.writeTo(out);

-

- dataChannelAddress.writeTo(out);

+ Util.writeAddress(dataChannelAddress, out);

 }



 // Public --------------------------------------------------------

So, looking for input from the JBM team as to

a) use of JGroups 2.8 in AS 5.2 in general, i.e. compatibility with JBM
b) possibility of getting the above in a JBM 1.x release for inclusion in AS 5.2.

[gaohoward]

Hi,

I think if jgroups 2.8 no longer supports its old API then I think it's the best time to update JBM to hornetq.

JBM 1.4 is in maintenance mode. It's important to keep it compatible with existing users who is still using jgroups prior to 2.8.

This is only my personal opinion.

Howard

[brian.stansberry]

This is not an API change in JGroups. Rather it's that JGroups users (AS, JBC, JBM) have been abusing the API by casting the type exposed by the API to an internal implementation class. (OK, in the code patched below there wasn't an explicit cast, but the effect was the same.)

I personally would love to see hornetq replace JBM. My understanding from Jason is a lot of the management stuff in the AS in pretty intimately tied to JBM, making the switch not practical for AS 5.2.

BTW, when is hornetq going to replace JBM in AS trunk? (5.2 will come off of AS Branch_5_x).

[timfox]

No-one from AS team has, as yet, discussed timescales for upgrading AS to use HornetQ with me, but if you like, you can start a discussion on the HornetQ dev forum about this.

[brian.stansberry]

Ah, of course, new forum is why this forum suddenly went silent a month ago!

I'll start a thread on the AS 6 conversion to hornetq there.

Meanwhile, Tim, any thoughts you have on the current topic would be most appreciated.

[brian.stansberry]

The HornetQ thread:

http://www.jboss.org/index.html?module=bb&op=viewtopic&t=161702