Re: [aspectj-users] Monitoring all method calls exception

["Rob Austin" <austirob@xxxxxxxxxxxxxx>]

Andy,

 

Another question off the back of this one it you don't mind.

 

Is it possible to use getSignature().getDeclaringType() to get a reference to the object to which it refers?

 

Essentially, I'm writing some code which monitors certain obects. If a method is called on one of these objects by some code which is not authorised to do so I want to terminate the object before it is compromised, so I want to get a reference to it to call its takeDown() method. The objects may be of different types but they all have a takeDown() method, but as I don't know the target type in advance, I can't use && target() I presume.

 

 

Really appreciate your help

 

Thanks

 

Rob

 

 

 

On 07/11/2007, Rob Austin <austirob@xxxxxxxxxxxxxx> wrote:

That's marvellous Andy, thanks so much

On 07/11/2007, Andy Clement <andrew.clement@xxxxxxxxx > wrote:

Your pointcut will catch static method calls.  At the call to static
method there is no target instance, and so thisJoinPoint.getTarget()
will return NULL, hence the NPE.  If you want the classname of the
target, use getSignature().getDeclaringType()

You should write !within(mypackage.bookTrading.*) and not
within(!mypackage.bookTrading.*) as the latter will not exclude inner
types and it looks like you have one of those because of the access$0
shown in your output.  I imagine you really also want to exclude
subtypes too, so it would be !within(mypackage.bookTrading..*)

cheers,
Andy.


On 06/11/2007, Rob Austin <austirob@xxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> I want to write an aspect that logs any call to my Package (myPackage) from
> outside of it - those I don't expect in other words.
>
> I'm facing the following problems with my newbie code:
> 1. I  thought I could restrict my advice to  calls made outside of my
> package by using within(! myPackage.bookTrading.* ) , but as you can see in
> the output below, it still seems to include calls made from within my
> package.
>
> 2. Where a call is to a method contained in a jar rather than in code for
> which the source is included in the project, thisJoinPoint
> .getTarget().getClass errors out with a nasty message, something along the
> lines of "Attempt to send a message to a non object value". I assume that
> this behaviour would be expected, but any ideas how I can trap for this
> rather than letting an error be raised.
>
> Really appreciate any help,
>
> Thanks
>
> Rob
>
>
>
> public aspect WatchMethodCalls {
>
>
> pointcut WatchAll(): call(* myPackage ..*.*(..))
> && within(! myPackage.bookTrading.*) && within(! WatchMethodCalls);
>
>
>
> before( ) :  WatchAll( )
>
> {
>     System.out.println("thisJoinPoint.getTarget ().getSignature() "
> +thisJoinPointStaticPart .getSignature());
>     System.out.println("thisJoinPoint.getTarget().getSourceLocation() " +
> thisJoinPointStaticPart .getSourceLocation());
>     System.out.println("thisJoinPoint.getTarget().getClass() " +
> thisJoinPoint .getTarget().getClass());
>
>
>
> }
>
> Sample output;
>
> thisJoinPoint.getTarget ().getSignature() Vector
> myPackage.bookTrading.BookBuyerAgentMalicious.access$0 (BookBuyerAgentMalicious)
> thisJoinPoint.getTarget().getSourceLocation()
> BookBuyerAgentMalicious.java:288
>
> Error occurred in WatchAll: java.lang.NullPointerException
> at
> apoptotic.BlockMethodCalls.ajc$before$apoptotic_BlockMethodCalls$1$2e232b3e
> (BlockMethodCalls.aj:22)
> at
> apoptotic.bookTrading.BookBuyerAgentMalicious$BookNegotiator.action (BookBuyerAgentMalicious.java:288)
> at
> jade.core.behaviours.Behaviour.actionWrapper(Behaviour.java :340)
>
>
>
>
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>
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