[aspectj-dev] Enhancement request/suggestion to define synchronized as a

[Ray Sutton <tardis@xxxxxxxxxx>]

I’m relatively new to AOP/AspectJ and new to this list; if this topic  
has previously been discussed I apologize for wasting people’s time.

Enhancement Request/Suggestion:

I can see some value in exposing the synchronized verb as an AspectJ  
join point.

Scenario/Use Case:

In my experience it is reasonably common for an application to behave  
reasonably in a pre-production environment but to perform badly under  
load, the cause often proves to be a synchronization issue. To make  
matters worse, in my experience, the source typically turns out to be  
a third party jar over which we have no control.

I believe a synchronized join point could help as a diagnostic tool  
to assist in investigating such problem in the following ways; and  
may have other applications as well.

1.     Providing the ability to track elapsed time of synchronized  
methods and blocks

2.     Providing the ability to log execution sequences leading to  
lock contention.

3.     Providing, through late weaving, the ability to investigate  
the behavior of classes shipped only in binary form.

4.     Provide the ability to be very specific in the targeting of  
instrumentation, thus minimizing the impact on the system under  
investigation.


Commercial products exist that provide similar capability but theses  
are typically very expensive.

Possible additional benefits

1.     Ability to enforce synchronization on selected variables at  
compile time.

2.     Ability to retrofit synchronization to existing code.


Issues:

1.     Before advise may need a modifier to select between arrival at  
the join point and acquisition of the monitor.

2.     Possible issues with the execution state with respect to  
synchronization of code within the advise.


Ray Sutton