The enums are potentially just as confusing. Does continue mean
"continue execution" or "continue shutdown"?
The shutdown() method is only meant to be invoked by the application
context. Maybe it should be protected so that only subclasses and the
org.apache.pivot.wtk package could see it. However, Application is an
interface so that's not possible.
The conversation between the application context and the application
might go like this:
App context: "It is time to shut down. You can say no if you want." -
> shutdown(true)
Application: "I don't want to shut down right now." -> return true
(cancels shutdown)
or this:
App context: "It is time to shut down. You have no choice." ->
shutdown(false)
Application: "OK." -> return false (value doesn't matter since
shutdown is not optional)
I don't think there's anything terribly confusing about either of
these scenarios, or the return values.
On Jun 24, 2009, at 8:56 AM, Christopher Brind wrote:
Generally you should avoid double negative testing which I think is
what
would happen here...
*Scenario 1:*
boolean shouldShutdown = shutdown();
if (shouldShutdown) {
System.exit(0);
}
*Scenario 2:*
boolean dontShutdown = shutdown();
if (!dontShutdown) { // double negative
System.exit(0)
}
I think Scenario 1 is easier to understand.
Alternatively why not return an enum?
public enum ShutdownResponse { CONTINUE, ABORT };
And change the signature to:
public ShutdownResponse shutdown();
Cheers,
Chris
2009/6/24 Greg Brown <[email protected]>
Most of the time my applications don't have any shutdown logic. So
the
shutdown() method is already a corner case.
Actually, most of our sample applications do. They close the main
window,
perform service logout, etc.
there are going to be times when the program does not have a
choice about shutting down (e.g. System Update forced a reboot).
Thus we need to separate the "can shutdown" flag from the
"shutting down
now" action.
That's why shutdown() takes a boolean "optional" argument. If
optional is
true, the method can return a value indicating whether it would
like to
cancel shutdown. If false (e.g. during reboot), the return value
will be
ignored.
I think the method signatures as currently defined are OK. They
parallel
(somewhat) the applet lifecycle methods. My question to you all was
- should
the return value of shutdown() mean "approve" or "deny"? It is
currently
defined as "approve", but I'm leaning towards changing it to the
latter.
