Re: return a Collection (Set or List)
thufir wrote:
The scanFile method returns a List. Sometimes, however, I want it to
return a Set. When I change the return type to Collection I get an error:
a00720398/data/BedAndBreakfast.java:33: incompatible types
found : java.util.Collection<a00720398.data.Guest>
required: java.util.List<a00720398.data.Guest>
guests = console.scanFile(new File("Guests.txt"), new GuestFactory
());
^
1 error
I've seen Collection used as a parameter in a signature, can it also be
used as a return type? A quick Google seems to show "yes".
You really should show the part of the code that actually has the problem. Read
http://sscce.org/
to find out how.
The problem is not the return of the Collection but its assignment to a
narrower type. You can assign a List<Foo> to a Collection<Foo> but not the
other way around.
If that's not what happened, but I'll bet it is, then you should have shown
the declaration of 'guests'. Or, for that matter, 'console' and 'scanFile()'.
--
Lew