Feedback and comments on ARM proposal

[Florian Weimer]

* Joshua Bloch:

> I think it might be easier to specify (and implement the package variant.
>  Roughly speaking, the legal types for "manageable resources" are those that
> are assignment compatible with one and only one of the classes in
> java.lang.auto.  While it's not generally possible to enumerate over classes
> in a package, the compiler can be (are, in fact) tied to particular versions
> of the platform so this shouldn't present too big a problem (though it could
> limit extensibility by JRE hackers).

If the interface has to reside in a package java.lang.auto.disposer,
you could name the interface by the name of the method, and generate
implementations automatically.  For instance,
java.lang.auto.disposer.foo would behave as if it were implemented as

    package java.lang.auto.disposer;
    
    public interface foo {
        foo() throws Exception;
    }

java.io.Closeable would look like this:

    package java.io;
    
    import java.io.IOException;
    
    public interface Closeable extends java.lang.auto.disposer.close {
        public void close() throws IOException;
    
    }

If some other language mechanism eventually made this obsolete, those
generated interfaces could likely incorporate this mechanism
automatically.

But perhaps this is too cute (but I think similar approaches where
proposed to deal with tuples).