Description Wes Isberg 2003-12-02 15:31:17 EST

Making inter-type member or parent declarations on a final class arguably
violates encapsulation.  Bytecode weaving makes this both more likely, and more
problematic.

For such declarations in a non-privileged aspect, the compiler should issue an
error.  This gives us a bright-line rule of thumb that encapsulation will be
preserved when not using privileged aspects.  However, this is not
backwards-compatible with some existing programs.  While it would be easy to fix
the code (if one has the source) by declaring the aspect privileged[1], doing so
means one is not protected from or notified about unintended access control
violations.

An alternative to making it an error is to use an XLint message, preferably with
a default level of error.  

Also, supporting "privileged" as a finer-grained access specifier would avoid
some of the problems above, and might be worth considering on its own merits:

aspect A {
  declare privileged parents: FinalTarget implements Runnable;

  public privileged boolean FinalTarget.run() {...}


  private fixup(privileged Foo foo) { // parser-eek!
      foo.privateVariable = null;
  }
  ...
}

In any case, we should document the issue.