I like the idea of this hybrid approach! I am NOT a fan of using javassist to write interceptors. I am writing an article for TheServerSide.com about HiveMind currently. Is this code available somewhere? I don't plan on demonstrating how to write a purely javassist-based interceptor, as I do not feel it is very intuitive. However, this simpler approach does seem to be a nice compromise and I would like to present it.
-----Original Message----- From: Christian Essl [mailto:[EMAIL PROTECTED] Sent: Tuesday, November 25, 2003 7:38 AM To: [EMAIL PROTECTED] Subject: [HiveMind] New interceptor support Javassist is fast and impressingly easy for byte-code generation, however it is by no way that comfortable (to code, test and debugg) as plain java. Therefore I've implemented an abstract ServiceInterceptorFactory which allows the user to attach MethodInterceptors to the methods of an interface. (A common pattern used by aopalliance, spring, cglib etc). Ie a simple tracing interceptor looks like this: public class TracingMethodInterceptor implements MethodInterceptor public Object invoke(Invocation invocation, Object target, Object[] args) throws Throwable { System.out.println("method: "+invocation.getMethod()+" is called with args: "+args); Object ret = invocation.proceed(target, args); //this invokes the next method in the interceptor chain System.out.println("method: "+invocation.getMethod()+" returned: "+args); return ret; } } Both the interceptor and the Invocation are created using Javassist, therefore it is in terms of speed (according to my rudimentary testings) between a plain Javaassist interceptor and a dyna-proxy interceptor. Comparing the existing Hivemind Logging with the same code using the MethodInterceptor and with a DynaProxy for 5.000.000 repetitions the times (ms) are as follows: (The numbers are not stable but the direction is quite clear) method: Object getObject() executing MethodLog took: 1000 executing HivemindLog took: 359 executing DynaProxyLog took: 1360 method: void setObject(Object); executing MethodLog took: 968 executing HivemindLog took: 516 executing DynaProxyLog took: 1766 method (9 prim params): int add(int,int,byte,short,char,double,long,float); executing MethodLog took: 3063 (more primitives and arguments means bigger args[] and boxing/unboxing) executing HivemindLog took: 594 executing DynaProxyLog took: 4031 As I see interceptors for general use should be created using javaassist, however other interceptors (which just add some custom AOP for some components) could well be implemented using MethodInterceptors. Here the higher convinience pays off. -- Christian Essl http://jucas.sourceforge.net --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
