[Engine-devel] Use java.util.Collection where possible?

[Danny Rankevich]

BWT I did some checks on the GWT RPC that we use (deRPC) and there shouldn't be any problems using Collection interface (or any interface) in the generic api service.

----- Original Message -----
> From: "Allon Mureinik" <amureini at redhat.com>
> To: "Yair Zaslavsky" <yzaslavs at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>
> Sent: Sunday, March 4, 2012 6:57:24 PM
> Subject: Re: [Engine-devel] Use java.util.Collection where possible?
> 
> My two cents:
> 
> There are two meanings of subtyping Collection (or any other
> interface, for that matter) - additional logic and specific
> implementation.
> I think wherever possible, we should use the interface that infers as
> much logic as possible (e.g., java.util.List for ordering,
> java.util.Set for uniquness, java.util.SortedSet for natural
> ordering, etc.), without inferring any specific implementation
> (e.g., ArrayList, HashSet, etc.).
> 
> The flipside of this notion is that it's a mistake to use an overly
> specific class/interface - when your parameter type is ArrayList,
> you implicitly tell the user the *order* of his objects matter, and
> that it matters to your internal algorithm to be able to do get(i)
> as an O(1) operation.
> 
> Bottom line,  now that I'm done with CS 101:
> +1, but be careful not use interfaces that are too low.
> Most methods that now receive an ArrayList will still compile if you
> change the parameter type to Collection, but make sure that you
> don't implicitly assume some ordering, e.g.
> 
> -Allon
> 
> ----- Original Message -----
> > From: "Yair Zaslavsky" <yzaslavs at redhat.com>
> > To: "engine-devel" <engine-devel at ovirt.org>
> > Sent: Thursday, March 1, 2012 5:18:03 PM
> > Subject: [Engine-devel] Use java.util.Collection where possible?
> > 
> > Hi,
> > I see that in some places in engine-core we use Java.Util.List, or
> > even
> > Java.Util.ArrayList as types of method arguments, while in the
> > method
> > code we do nothing besides iterating over the collection.
> > I then found all kinds of usages like this:
> > 
> > x.foo(new ArrayList<MyType>(myMap.values()));
> > 
> > As you can see need to instantiate a new ArrayList in order to use
> > the
> > values of the map in method foo.
> > Do you see any reason why not change the argument type (at method
> > signature) to Collection in such places, where possible?
> > 
> > Yair
> > 
> > _______________________________________________
> > Engine-devel mailing list
> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > 
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