I just posted a message to commons about aspectj. :) Very, very cool stuff+ACE- What I'd like to see next from that arena is the ability to define pointcuts and aspects dynamically rather than with a recompile.
Donnie +AD4- -----Original Message----- +AD4- From: Nicholas Lesiecki +AFs-mailto:nick+AEA-eblox.com+AF0- +AD4- Sent: Thursday, January 10, 2002 5:52 PM +AD4- To: Struts Developers List +AD4- Subject: AspectJ and Struts Exception handling: +AD4- +AD4- +AD4- Hello, +AD4- +AD4- A while back Rick Hightower submitted a request to change the way +AD4- Struts handles errors. His problem (and mine) is that Struts +AD4- tends to catch exceptions and throw different exceptions +AD4- indicating the problem. Needless to say this can badly obscure +AD4- the original cause of the error. +AD4- +AD4- So today I set about remedying it using AspectJ--an aspect +AD4- oriented extension to Java produced by Xerox PARC +AD4- (http://www.aspectj.org). I added the following aspect to the +AD4- org.apache.struts package: +AD4- +AD4- public aspect ExceptionLogger+AHs- +AD4- +AD4- before(Throwable e) : args(e) +ACYAJg- handler(Throwable+-)+AHs- +AD4- System.err.println(+ACI-Exception caught in the Struts framework:+ACI-)+ADs- +AD4- e.printStackTrace(System.err)+ADs- +AD4- +AH0- +AD4- +AH0- +AD4- +AD4- Then I compiled Struts with an Ant task for AspectJ compilation: +AD4- +AD4- +ADw-target name+AD0AIg-compile.library+ACI- depends+AD0AIg-prepare.library+ACI- +AD4- description+AD0AIg-Compile Struts library files+ACIAPg- +AD4- +ADw-ajc srcdir+AD0AIgAkAHs-src.share.dir+AH0AIg- +AD4- destdir+AD0AIgAkAHs-build.home+AH0-/library/classes+ACIAPg- +AD4- +ADw-classpath refid+AD0AIg-compile.classpath+ACI-/+AD4- +AD4- +ADw-/ajc+AD4- +AD4- +AFs-...task continues as normal...+AF0- +AD4- +AD4- Now all exceptions caught in the Struts framework are +AD4- automatically logged to System.err. +AD4- +AD4- So my question is: +AD4- +AD4- Should we consider the use of AspectJ in Struts? This would +AD4- potentially have no effect on the users of the framework, but +AD4- could be valuable for implementing logging and error-handling +AD4- policies. The above code could be modified to write to a log4j +AD4- log if that would be more convenient. +AD4- +AD4- Does this intrigue anyone? Should we continue investigation? +AD4- +AD4- Cheers, +AD4- +AD4- Nicholas Lesiecki +AD4- +AD4- (For more info on AspectJ, look for my forthcoming article on +AD4- IBM's developerWorks.) +AD4- +AD4- Technical Team Lead +AD4- eBlox, Inc. +AD4- (520) 615-9345 x104 +AD4- Check out my new book+ACE-: +AD4- Java Tools for Extreme Programming: Mastering Open Source Tools, +AD4- including Ant, JUnit, and Cactus +AD4- +AD4- http://www.amazon.com/exec/obidos/ASIN/047120708X/ +AD4- +AD4- +AD4- +AD4- +AD4- -- +AD4- To unsubscribe, e-mail: +ADw-mailto:struts-dev-unsubscribe+AEA-jakarta.apache.org+AD4- For additional commands, e-mail: +ADw-mailto:struts-dev-help+AEA-jakarta.apache.org+AD4- -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
