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From: "Howard M. Lewis Ship" <hlshiplists@comcast.net>
To: "'Jakarta Commons Developers List'" <commons-dev@jakarta.apache.org>
Subject: RE: [HiveMind] Interceptors - CGLIB / Javassist comparison
Date: Fri, 5 Mar 2004 13:57:38 -0500
Message-ID: <035201c402e3$badaf500$6401a8c0@ALMIGHTYBEAST>
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A valuable discussion. I think Javassist will have a slight edge based on lack of object
instantiation in the long run. I may be wrong. Doesn't really matter ... that why
ServiceInterceptorFactory is a service ... we may ultimately have all kinds of different
implementations based on whatever bytecode enhancement framework is handy ... or even JDK proxies.

--
Howard M. Lewis Ship
Independent J2EE / Open-Source Java Consultant
Creator, Tapestry: Java Web Components 
http://howardlewisship.com


> -----Original Message-----
> From: Harish Krishnaswamy [mailto:hkrishnaswamy@comcast.net] 
> Sent: Friday, March 05, 2004 1:45 PM
> To: Jakarta Commons Developers List
> Subject: Re: [HiveMind] Interceptors - CGLIB / Javassist comparison
> 
> 
> Seems that's what you said before ;) But nevermind this is a 
> more-than-enough-pointer!
> 
> -Harish
> 
> Christian Essl wrote:
> 
> > Sorry I made a mistake I meant ProxyFactory.extend() not create().
> >
> > On Fri, 05 Mar 2004 13:37:06 -0500, Harish Krishnaswamy 
> > <hkrishnaswamy@comcast.net> wrote:
> >
> >> Absolutely! Thanks for the tips. So that's what I'll do.
> >>
> >> -Harish
> >>
> >> Christian Essl wrote:
> >>
> >>> Hi Harish,
> >>>
> >>> I agree with you that HiveMind should provide a simpler (second) 
> >>> form to write interceptors.
> >>>
> >>> But before you waste your weekend looking at my code I 
> have to tell 
> >>> you that I did not use CGLIB but rather used Javassist to call 
> >>> MethodInterceptors. And this was a mistake CGLIB is 
> certainly better 
> >>> for that.
> >>>
> >>> If you want to see how CGLIB is used take a look at one of the 
> >>> aop-frameworks dynaop, spring or nanning.
> >>>
> >>> I persanlly like dynaop (while they use CGLIB 1) 
> according to there 
> >>> website dynaop is faster than the others (even than JBoss aop - 
> >>> which uses Javassist). Dynaop is also well documented and not too 
> >>> complex - while you can learn a lot. To start look at the 
> >>> ProxyFactory.extend() method - as I see cglib is used 
> only from in 
> >>> there - and take a look at the 
> ClassProxyInvocationHandler and its 
> >>> super-class.
> >>>
> >>> I hope this helps a bit (certainly more than my code).
> >>>
> >>> Thanks,
> >>> Chris
> >>>
> >>>
> >>>
> >>> On Fri, 05 Mar 2004 13:06:05 -0500, Harish Krishnaswamy 
> >>> <hkrishnaswamy@comcast.net> wrote:
> >>>
> >>>> Oops, sent to the wrong list!
> >>>>
> >>>> Harish Krishnaswamy wrote:
> >>>>
> >>>>> Hi,
> >>>>>
> >>>>> I decided to do some work on interceptors and wanted to find a 
> >>>>> suitable solution and so tried out CGLIB and Javassist and here 
> >>>>> are my initial findings.
> >>>>>
> >>>>> 1. Ease-of-use / clarity / maintainability - Obviously here, 
> >>>>> anybody that has done a little bit of Javassist will 
> agree that it 
> >>>>> is in no way comparable to CGLIB when it comes to ease-of-use. 
> >>>>> CGLIB is all plain Java and very straight forward and 
> Javassist is 
> >>>>> on the other end of the spectrum - pieces of string literals 
> >>>>> patched together to form Java statements.
> >>>>>
> >>>>> 2. Performance - This is interesting. CGLIB has a disadvantage 
> >>>>> here due to the number of parameters passed to the intercept 
> >>>>> method. It turns out, all of the overhead is because of these 
> >>>>> parameters that cannot be overcome (atleast AFAIK). 
> With a single 
> >>>>> counter interceptor I could make Javassist as much as 
> ~4 times as 
> >>>>> fast as CGLIB (~300% faster). And with more 
> interceptors obviously 
> >>>>> Javassist is more faster. Now, if I insert a method call in the 
> >>>>> Javassist interceptor with 4 parameters, to my surprise the 
> >>>>> performance is identical to the CGLIB interceptor. 
> Would be really 
> >>>>> nice if CGLIB can be designed around this problem.
> >>>>>
> >>>>> 3. Limitations - There are quite a few limitations with 
> Javassist 
> >>>>> that can be found on their website primary one for me being not 
> >>>>> able to debug instrumented classes. I have not come across any 
> >>>>> such limitations with CGLIB.
> >>>>>
> >>>>> From this intial study, it looks to me that we certainly need a 
> >>>>> way to provide CGLIB interceptors to services. And that's what 
> >>>>> I'll be doing this weekend. I know Christian has 
> already done some 
> >>>>> work on this, I'll see if I can reuse it.
> >>>>>
> >>>>> -Harish
> >>>>>
> >>>>> PS. I can post the code if anybody is interested.
> >>>>>
> >>>>>
> >>>>
> >>>> 
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> >>>
> >>>
> >>
> >> 
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