[Jboss-dev-forums] [Design the new POJO MicroContainer] - Re: AOP/Metadata integration config

[<bil...@jb...>]

anonymous wrote : 
  | Ok, let's deal with a fundamental problem first.
  | 
  | The MC does not necessarily use a ConstructorJoinPoint.
  | It could use a factory to create the object. See the ConstructorMetaData.
  |  
  | 

The AOP container needs to intercept the allocation of the bean by the MC.  Whether this is done by a constructor or factory method, it doesn't matter. AOP needs to intercept allocation so that it can put a proxy in place or initialize the InstanceAdvisor (depending whether the class is aspectized or not).

What I think we should do is ditch the ClassAdapter stuff and just have an AspectAdapter.  An AspectAdapter should be created per bean.  This would require a rewrite of your MC because allocation information and the ClassAdapter stuff is embedded within the BeanInfo class which is cached on a per-class basis.

I think the AspectAdapter interface should be as follows in live within the kernel/ module:


  | public interface AspectAdapterFactory {
  |    AspectAdapter createAspectAdapter(Class clazz, BeanMetaData metadata);
  | }
  | 

Yes, AOP Requires the java.lang.Class.  Again, I refuse to use ClassInfos because it would require too much refactoring to JBoss AOP and creating ClassInfos with Javassist, is just way too slow.  I have no desire to refactor Javassist as well to make it faster.  I think you are going way overboard with dependency management here.  Requiring too much work for too little reward.

The AspectAdapter interface might look something like this:


  | public interface AspectAdapter {
  |    public List getDependencies();
  |    public ConstructorJoinpoint getConstructorJoinpoint(ConstructorInfo);
  |    public MethodJoinpoint getFactoryJoinpoint();
  |    public FieldGetJoinpoint getFieldGetJoinpoint(FieldInfo);
  |    public FieldSetJoinpoint getFieldSetJoinpoint(FieldInfo);
  |    public MethodJonipoint getMethodJoinpoint(MethodInfo);
  | }
  | 

For JBoss AOP at least, the getMethodJoinpoint would not be needed.  FieldGet/FieldSet are needed because JBoss AOP wraps field access in a static method call.  A separate getFactoryJoinpoint and getConstructorJoinpoint is needed, because again, JBoss AOP needs to be able to intercept allocation to create a proxy or to interact with the aspectized class's object instance's InstanceAdvisor.

This is going to require a bunch of refactoring to MC because currently the classadapter is hidden by BeanInfos.

Bill


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