Hello,
On 8/1/2013 5:28 AM, Jean-Baptiste Bugeaud wrote:
Hello,
As a follow-up from Joe Darcy's proposal (2013-02-06) to add
@FunctionalInterface to some interfaces matching the requirements of
FI.
I propose that this improvement is applied to all the VM Java libs.
Doing a quick search, I've found some interfaces are not tagged as
FunctionaInterfaces but clearly look good candidates :
Here is the list of public API I have found so far :
java.security.PriviledgeAction
java.awt.event.ActionListener
java.lang.util.concurrent.Callable
java.util.Formattable
javax.management.remote.JMXAddressable
javax.naming.Referenceable
java.awt.print.Printable
I found the candidate interfaces by running an annotation processor over
the JDK codebase:
"Functional Interfaces"
https://blogs.oracle.com/darcy/entry/functional_interfaces
A bug was filed for analogous API review in the swing area:
JDK-8007716 Add FunctionalInterface annotation to swing interfaces
and other client teams were contacted as well (2D team on Feb. 8, etc.),
but that work has not been done yet. Thanks for the reminder.
The general guidance given at the time was:
To a first approximation, if a candidate type today is commonly
created using anonymous inner classes, it is reasonable to add the
functionalInterface annotation. Note that the compiler will allow any
type meeting the structural requirements of a functional interface to
be used in a lambda expression; the annotation just provides
documentation of intent.
There are also a few core libs are interfaces where we may want to
re-examine if @FI is really needed.
Thanks,
-Joe
