Ramnivas:
Just want to
clarify some of the points you brought up.
Here is what my
customer class looks like. “.
Essentially I would like to narrow the join points
based on exception type and not catch for e.g all runtime exceptions and have a
big switch in my advice. Here is a sample code I used in my test earlier
e.g.
Are you weaving into classes throwing the exceptions?”
-- Perhaps you could help clarify what you mean by weaving into the
class.
public class
Customer {
public
Customer() {
System.out.println("customer
constructor");
}
public
String getName(String type) throws NullPointerException,
BufferOverflowException,
MissingResourceException {
System.out.println("exception
requested is of type:" + type);
if
(type.equals("null")) {
throw
new NullPointerException("null");
}
else if (type.equals("buffer")) {
throw
new BufferOverflowException();
}
else if (type.equals("missing")) {
throw
new
MissingResourceException("missing","missing","missing");
}
return
"test";
}
}
With my point cut
defined as
ublic aspect
ExceptionHandler {
//pointcuts
to specify joinpoints -- collect specific contexts of interest
pointcut
customException():
(call
(* *.*(..) throws NullPointerException)
||
call (* *.*(..) throws BufferOverflowException)
||
call (* *.*(..) throws MissingResourceException))
&&
within (HelloWorld);
//
advices or actions that we need to take
after()
throwing (RuntimeException ex): customException() {
System.out.println("In
after throwing advice");
if
(ex instanceof MissingResourceException)
System.out.println("advice:
Found missing resource");
else
if(ex instanceof NullPointerException)
System.out.println("advice:
Found Null Pointer");
else
if(ex instanceof MissingResourceException)
System.out.println("advice:
Bufferoverflow");
throw new CustomException(ex);
}
}
the number of
visible advices when using AJDT 1.2 is confined to
the only those that throw these exceptions; however, when I use the pointcut
you sent me, every line of my code seems to have a advice attached to it. In
eclipse 3.0/ajdt 1.2, I have that advised-by-arrow suddenly show up all over
the code.
pointcut customException():
call (* *.*(..)
&&
within (HelloWorld);
-
Sudhakar Ramakrishnan
x3520, ESRI
From: Ramnivas Laddad [mailto:ramnivas@xxxxxxxxxxxxxxx]
Sent: Tuesday, August 30, 2005
11:53 AM
To: aspectj-users@xxxxxxxxxxx
Subject: Re: [aspectj-users]
Exception Handling PointsCuts/Advices
execution() vs. call() shouldn't really matter in you
case. Are you weaving into classes throwing the exceptions? If not, that
explains why call() works and not execution().
Also, there is a kind of bug in you pointcut: you are specifying runtime
exceptions as a part of your pointcuts. Since runtime exceptions specification
of methods, if any, is lost in the byte code, you pointcut is effectively the
same as the following:
pointcut customException():
call (* *.*(..)
&& within (HelloWorld);
This bug, however, is unrelated to execution() vs.
call() issue.
-Ramnivas
===
Ramnivas Laddad,
Author, AspectJ in Action
http://ramnivas.com
M: (408)203-4621
Sudhakar Ramakrishnan wrote:
If I use execution pointcuts, then the exception gets throw in the code
and it never gets caught in the after throwing(). So I repaced them with
the call point cut. Is this correct?
public aspect ExceptionHandler { //pointcuts to specify joinpoints -- collect specific contexts
of interest
pointcut customException():
(call (* *.*(..) throws NullPointerException)
|| call (* *.*(..) throws BufferOverflowException)
|| call (* *.*(..) throws MissingResourceException))
&& within (HelloWorld);
// advices or actions that we need to take
after() throwing (RuntimeException ex): customException() { System.out.println("In after throwing advice"); if (ex instanceof MissingResourceException)
System.out.println("advice: Found missingresource");
else if(ex instanceof NullPointerException)
System.out.println("advice: Found NullPointer");
else if(ex instanceof MissingResourceException)
System.out.println("advice: Bufferoverflow");
throw new CustomException(ex);
}
}
-
Sudhakar Ramakrishnan
x3520, ESRI
-----Original Message-----
From: Ramnivas Laddad [mailto:ramnivas@xxxxxxxxxxxxxxx]
Sent: Tuesday, August 30, 2005 11:21 AM
To: aspectj-users@xxxxxxxxxxx
Subject: Re: [aspectj-users] Exception Handling PointsCuts/Advices
You are almost there. Try the following advice instead:
after() throwing(RuntimeException ex): customException() { // use ex...
// do some processing with the exception object, like logging etc
throw new CustomException(ex); // chaining 'ex' is a good idea
}
-Ramnivas
===
Ramnivas Laddad,
Author, AspectJ in Action
http://ramnivas.com
M: (408)203-4621
Sudhakar Ramakrishnan wrote:
How would one go about define pointcuts and advices for something like
this?
Class A throws a number of different types of unchecked exceptions. I
want to define a pointcut that captures these execution join points,
catch the unchecked exception, do some processing with the exception
object, and possibly rethrow the exception as a custom exception. If
anyone has samples for this it would be great.
More details:
Let's say we have
Class A:
public void createAccount(String type) { if (type.equals("aaa")) { throw new NullPointerException("aaa"); } else if (type.equals("bbb")) { throw new BufferOverflowException();
} else if (type.equals("cccc")) { throw new
MissingResourceException("missing","missing","missing"); }
}
We create Class A objects in Class B.
Class B:
A obj = new A();
Try {A.createAccount();
} catch (CustomException e) { // hoping aspectj has rethrow certain unchecked exceptions as
customexceptions
}
Essentially, I want to capture some of those unchecked exceptions and
cast it into a customexception. If there are checked I will convert
them
to soft exceptions and convert them if needed.
I am starting with something like this and want some help since I am
new
to AspectJ syntax.
public aspect ExceptionHandler { pointcut customException():
(execution (* *.*(..) throws NullPointerException)
|| execution (* *.*(..) throws BufferOverflowException)
|| execution (* *.*(..) throws
MissingResourceException))
&& within (A);
// I guess I need after throwing
after() : customException() { //do some processing with the exception object, like logging
etc
throw new CustomException();
}
}
-
Sudhakar Ramakrishnan
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