Depending on a MBean

[bill.burke]

Ran into a funny problem. I wanted an MDB in JBoss 5 to depend on a Queue so that it wouldn't try to create a temporary queue. So, I added a @Depends tag to what I typed in the service.xml file.

The problem is, that the MBean deployer registers a canonical name with the registry and didn't realize that the @Depends tag didn't match the canonical name (but it did match the name in the service.xml file)

People are going to run into this problem all over the place.

My first suggestion would be to register the string and not the canonical name. So that users won't make the mistake.

[starksm64]

Carlo brought this up before and it looks like the canonical name should be used. Still need to track down where a toString is slipping in.

[bill.burke]

NO, what I'm saying is that the string that is specified in the XML should be used as the kernel name. Otherwise, users won't know what the freakin problem is when they create a dependency.

[adrian.brock]

NO! :-)

What I told Carlo is to do what is done in the system-jmx xml parsing.
e.g. when you "parse" the @Dependency or where-ever else
you are creating dependencies that might be JMX or POJO.

i.e.

 String iDepend = ...

 Object other = iDependOn;
 try
 {
 other = new ObjectName(iDependOn).getCanonicalName();
 }
 catch (MalformedObjectNameException ignored)
 {
 // Not a JMX object name
 }

[bill.burke]

NO! That doesn't work either because of our propensity to use object name strings in bean names.

[bill.burke]

What i'm saying is:

@Depends("jboss.something:service=blah,name=Foo")
@Stateless
public class MyBean {}


The depends could be a Jmx mbean or ajust a regular MC bean that is using an string that looks like an object name as its key/name. I don't want to introduce a @JmxDepends or a

<jmx-depends>

then again, maybe we have to.

[adrian.brock]

If you're going to use a JMX like object name as a pojo name
then you should really make it canonical form.

We could hack the AbstractController[Context] such that it also
converts ObjectName like strings to canonical form even if they aren't actually a
JMX deployment

[bill.burke]

you'd have to do it for everything. Demands, Dependency, etc...

[bill.burke]

btw, what is a canoical name? alphabetical sorting of key fields?

[bill.burke]

created issue here. Assigned to Ales. Made it critical feature as I believe many people will run into it. Especially with MDBs.

[bill.burke]

http://jira.jboss.com/jira/browse/JBMICROCONT-166

[adrian.brock]

btw, what is a canoical name? alphabetical sorting of key fields?

Nearly. The "type=" property is treated specially in the spec. It always
comes first in the canonical form.

[adrian.brock]

http://jira.jboss.com/jira/browse/JBMICROCONT-166

I'm just writing some testcases so we can understand the problem
and make sure it gets fixed. So I'll take it.

[starksm64]

btw, what is a canoical name? alphabetical sorting of key fields?

Yes, from the ObjectName javadoc:

'jdk5 javadoc" wrote:

public String getCanonicalName()

Returns the canonical form of the name; that is, a string representation where the properties are sorted in lexical order.

More precisely, the canonical form of the name is a String consisting of the domain part, a colon (:), the canonical key property list, and a pattern indication.

The canonical key property list is the same string as described for getCanonicalKeyPropertyListString().

The pattern indication is:

* empty for an ObjectName that is not a property pattern;
* an asterisk for an ObjectName that is a property pattern with no keys; or
* a comma and an asterisk (,*) for an ObjectName that is a property pattern with at least one key.

Returns:
The canonical form of the name.