On Feb 1, 11:02 pm, Casper Bang <[email protected]> wrote:
> Correct me if I am wrong, only Apple employees are
> allowed to do real multi-threaded apps?
My pleasure. :-)
iOS had always had support for multi-threading inside an app as part
of the SDK:
- There's a low level thread API.
- There's a higher level API where you create a "NSOperationQueue",
specify how many tasks to run in parallel and then fill it with tasks
("NSInvocationOperation") that each have a selector (read: function
pointer). So it's similar to using a thread pool from
java.util.concurrent with objects implementing Runnable.
- Finally, iOS 4 added Grand Central Dispatch (GCD), a supposedly very
efficient way to run threads and to switch between them (http://
en.wikipedia.org/wiki/Grand_Central_Dispatch). It's a C-based API
that was introduced in OS X 10.6 (iOS 4 being the equivalent of OS X
10.6, iOS 5 probably matching 10.7). I think "NSOperationQueue" uses
it under the hood. GCD is open source with an Apache license and
seemed to me a strong indicator at the time that this year's iOS
devices will have dual-core CPUs.
As for multi-tasking, see my other post. Downloading data in the
background has been often requested by app developers since it's not
available today in the SDK. Rumor has it that in the "iPad-only
newspaper by Fox" event today, Apple will not only announce
subscription payment for iTunes / iOS, but also background downloading
of said newspaper. This may mean that in iOS 4.3 (March?) or 5.0
(June/July?), apps can periodically download data, too, in an
extension of today's public multi-tasking. Apple already does that
with push-based delivery of emails and updates to the address book or
the calendar.
--
You received this message because you are subscribed to the Google Groups "The
Java Posse" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/javaposse?hl=en.
