Description George Harley 2003-07-20 12:16:58 EDT

At present the declare warning and declare error functionality of the compiler 
provides no detailed information about what it is in the user code that has led 
to the generation of the compile-time warning or error. 

Consider the following test case...

public class A
{
  public static void main(String[] args)
  {
    A a = new A();
    a.doSomething();
    System.out.println("All done");
  }

  void doSomething()
  {
    System.out.println("Doing something");
  }
} // end of class A


public aspect MyAspect
{
  pointcut noDoing() :
    call(* *.doSomething(..));

  declare warning : noDoing() :
    "Don't do it!";
} 

When I compile these two files I get the following warning ...

c:\src\A.java:16 Don't do it!

..which is great if all I want to know is where the offending code is. But not 
nearly enough if I want to know what it is on the line that is contravening the 
policy (or policies) that I have specified in my aspect. In the above example it 
would be even more useful if the warning message was something like ...

c:\src\A.java:16 Don't do it! : calling method : void A.doSomething()

For large projects where there is an architectural imperative to reduce or 
completely remove coupling between certain components declare warning/error 
would be of far greater use if it could return more detailed info to say *why* 
not just *where* the desired enforcement rules have been broken.