Skip to main content

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
RE: [aspectj-users] Why is toString matched?


Thanks for the help, Ron.   I'm quite new to aspectj, and I suspected it was because in java "everything extends Object" that was causing me to get bit.  I was quite suprised by this behavior.   Lots of gotchas for the aspectj noob!

Thanks,
Brian Yoffe



"Ron Bodkin" <rbodkin@xxxxxxxxxxxxxx>
Sent by: aspectj-users-bounces@xxxxxxxxxxx

08/21/2006 02:51 PM

Please respond to
aspectj-users@xxxxxxxxxxx

To
<aspectj-users@xxxxxxxxxxx>
cc
Subject
RE: [aspectj-users] Why is toString matched?





Hi Brian,
 
AspectJ appears to be considering these methods as matching because they are defined on Object. In some sense AspectJ considers that MyInterface extends Object, just as in Java you can invoke methods on Object when you have an instance of an interface, without downcasting. You can work around this behavior by excluding methods defined on Object, e.g.,
 
    protected pointcut nonVoidMethod() :
        execution(public !void (@ServiceCallback *).*(..)) && !execution(* Object.*(..));
 
However, I think it would be better if AspectJ didn’t consider methods defined on Object as being defined on an interface unless the interface explicitly declares them. So I think this should be a bug, although maybe there’s a use case for why it should match?
 
Here’s a similar program that shows the core issue without annotations (all the methods on MyInterfaceImpl):
 
public interface MyInterface {
   void doWork();
   int getValue();
}
 
class MyInterfaceImpl implements MyInterface {
   public void doWork() {}
   public int getValue() { return 0; }
   public String toString() { return "x"; }
}
 
aspect MatchMyInterface {
   declare warning: execution(* MyInterface.*(..)): "method on my interface";
}
 



From: aspectj-users-bounces@xxxxxxxxxxx [mailto:aspectj-users-bounces@xxxxxxxxxxx] On Behalf Of brian.a.yoffe@xxxxxxxxxxxx
Sent:
Monday, August 21, 2006 7:42 AM
To:
aspectj-users@xxxxxxxxxxx
Subject:
[aspectj-users] Why is toString matched?

 

I'm trying to create a policy that enforces the following:


Any interface that is marked with the @Callback annotation cannot have methods that are non-void.


That is:


@Callback

public interface MyInterface {

  void doWork();

  int getValue();

}


public class MyInterfaceImpl implements MyInterface {

  void doWork() {...}                //   <---- just fine, as pectected

  int getValue() {...}                //   <---- expect error here, and it is

  public String toString() {...}           //   <---- should be just fine, but it's included in the joinpoint and thus an error

}


I've tried to accomplish this using the following joinpoint/error:


   protected pointcut nonVoidMethod() :

       execution(public !void (@ServiceCallback *).*(..));

   
   declare error : nonVoidMethod() :

       "Non void method.";


However, the results I get indicate that public String toString() matches this joinpoint.


In further experimentation, I redefined the interface:


@Callback

public interface MyInterface {

  void doWork();

//   int getValue();   note, I commented this out of the interface

}


and here's the results


public class MyInterfaceImpl implements MyInterface {

  void doWork() {...}                //   <---- just fine, as expected

  int getValue() {...}                //   <---- would expect the same behavior as toString exhibits.   However, this is not an error anymore

  public String toString() {...}           //   <---- still an error

}


I am a bit lost - why is the toString joinpoint included by my pointcut?   How do I prevent it?


Thanks,
Brian Yoffe



This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates.

This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you.
_______________________________________________
aspectj-users mailing list
aspectj-users@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/aspectj-users



This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates.

This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you.

Back to the top