Re: [aspectwerkz-user] Hot deployment questions

Hi Vincent

inlined..

On Apr 10, 2005 11:00 AM, Vincent Massol <[email protected]> wrote:
> Hi,
> 
> I'm still trying to get hot deployment to work for Cactus2... I have now
> decided to try using JDK 5.0 to get started.
> 
> I have some questions:
> 
> 1/ On http://aspectwerkz.codehaus.org/dynamic_aop.html it says to use the
> following to get a deployment scope:
> 
> DeploymentScope scope = SystemDefinition.getDefinitionFor(loader,
> systemId).getDeploymentScope("toString");
> 
> However the SystemDefinition object does not have a static getDefinition()
> method. It does have a non-static method of this name though. How do I get a
> SystemDefinition object? Do I need to create one using "new"? If so what
> string should I pass? The same as the systemId defined in aop.xml?
> 

1/ accessing the definition model to get the scope
should be :
 DeploymentScope scope = SystemDefinitionCONTAINER.getDefinitionFor(loader,
 systemId).getDeploymentScope("toString");
No new() - that would not do anything.

> 2/ In
> http://blogs.codehaus.org/people/jboner/archives/000913_aspect_hot_deploymen
> t_in_practice_implementing_a_jmx_monitoring_aspect_.html, Jonas says, in the
> "Define a deployment scope" section:
> 
> "This can be done either in the META-INF/aop.xml file or using annotations
> in the aspect class"
> 

2/ aop.xml is mandatory in all cases
If the scope is defined as an annotation, ie in an aspect, then it is
mandatory to declare the aspect in aop.xml

> Thus it seems possible not to have anything defined in aop.xml. Thus
> something like this would work, right?
> 
> <aspectwerkz>
>  <system id="cactus2"/>
> </aspectwerkz>
> 

No, won't work (nothing would be prepared for the scope to be further used)

> 3/ Would it also work if I have a generic deployment scope such as:
> 
> <aspectwerkz>
>  <system id="cactus2">
>    <deployment-scope name="allcode" expression="within(..)"/>
>  </system>
> </aspectwerkz>
> 

3/ generic scope is supported (and that s the motivation of it: allow
deployment to a subset of that scope upon user/app needs but thus
under control by the deployer)
Yes, very generic scope should work. The idea there would be to deploy
to a subset of this wide scope


> 4/ If I use the Deployer.deploy(class, xmlDef) method, do I also need to
> define the xmlDef in the aop.xml file or can it be empty.
> 

4/ unrelated
aop.xml may contain a scope or an aspect that defines a scope - among
other things.
Then using this deploy(aspectClass, xmlDefThatRefineAspectClassAnnotationIfAny)
will deploy according to the usual deployment rule (annotation + xml override)
You should actually use the "scoped" version of this method:

    public static DeploymentHandle deploy(final Class aspect,
                                          final String xmlDef,
                                          final DeploymentScope
deploymentScope) {





>
> 5/ If the aop.xml file is empty, do I still need one?
>

From the previous answer, yes, one is mandatory, and it is actually not empty.

> Thanks and sorry for all those newbie questions but I really have a hard
> time understanding all this even though I have read and re-read at least 5
> times the docs on the web site ;-) I should probably read the source code to
> try to understand how it all works but then this is a bigger task which I
> would prefer not to start now :-)

Should we write a more comprehensice tutorial on that ?

> 
> Thanks
> -Vincent
> 


Alex