Re: [aspectj-users] no match for this type name...

[Ramnivas Laddad <ramnivas@xxxxxxxxx>]

Michael,

AspectJ developer have tried to improve error/warning messages
to make them clearer and user friendly. However, it is upto
us -- aspectj users -- to point out areas for improvement
and help by suggesting better messages. In fact, these
XLint warnings are a result of combination of user feedback 
and developer initiative; in pre-1.1 version, there were no
warnings at all and you would be wondering why program compiled
fine, but did not execute as expected.

For those who are seasoned to seeing this error message,
it is "once you know, you know" kind of situation. It is,
therefore, importnant that you, as a representive of 
newcomers to AspectJ, help by narrating your experience
and suggesting what would have been useful to you (which
you are already doing).

Okay, now onto the error message itself. It is a little 
complex to come with a simple error message. You could see
error message for one of the following reason:
1. Misspelled type name: In this case, the type won't exist
   anywhere in the system. This also includes case of fully
   specified type name with missed/misspelled packages.
2. Correctly spelled type name but missed package statement
   (and type not in the same package as the aspect): In 
   essense the type isn't visible to the aspect.
3. Type name specified as wildcarded package: This would be
   case when pointcut say something like call(com..MyTypeName.*(..)).
   In this case, you don't even need a package statement and 
   the program will still compile fine.
   (This situation is actually covered by a different XLint
    warning, which is turned off by default).

I think perhaps it will be best if you file this as a bug so that
it can be tracked and resolved in a new version of AspectJ.
I will add my input as a comment to that bug.

-Ramnivas

--- Michael McConnell <mcconnellem@xxxxxxxxx> wrote:
> Ramnivas -- At first I thought you were being sarcastic when you
> wrote:
> 
> > For the error message, how about something like:
> > "Unknown type MessageCommunicator. Please ensure correct 
> >  spelling and/or the type is visible to the source file
> >  (check your import statements or use the fully-qualified 
> >   type name)".
> 
> And then I saw the following:
> > The downside I see is sheer verbosity of the message.
> > Perhaps a better alternative is to point to document
> > that elaborates on "Xlint:invalidAbsoluteTypeName".
> 
> I think the latter is much more preferable than the former. But I
> think *BOTH* miss the
> point that I was trying to make earlier, which is: if I were using
> standard Java
> (with/without Eclipse), and I had forgotten the package statement, I
> would have gotten
> the following message: "The declared package does not match the
> expected package xxxxx". 
> 
> NOT the statement:  "no match for this type name: XXXX
> [Xlint:invalidAbsoluteTypeName]".
> 
> I mean --- this is almost as good as a 1970's ABEND NNNN statement.
> 
> In your book, you state that ajc is a superset of javac. Which is
> fine as far as it goes,
> but (I wish the AJC developers had decided to) add in the syntax and
> semantics that AOP
> requires, but *don't mess with standard java*, especially the error
> messages and warnings
> that you would expect to see if *writing standard Java*. If the
> package and import
> statements are valid within an aspect, treat them as they would a
> standard Java
> statement, and issue the standard messages we have all grown to know
> and love.
> 
> NONE of this is YOUR FAULT. However, there was a suggestion on this
> forum to start
> documenting errors like as to probable causes. As much as it would
> have helped me, I
> would prefer that aspect users get together and start demanding tools
> from ajc developers
> that build upon the knowledge that they already know, and do not
> require
> learning/generating differential diagnoses for symptoms they have
> never seen. 
> 
> FWTW,
> Michael
> 
> 
> =====
> 
> 
> 
> 	
> 		
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