Comment utiliser les Boulons de Cadre[Facebook+Parse]

Voici un exemple complet d'une application qui pourrait soutenir les multiples acteurs de la modification des données lors du traitement de mise en réseau des demandes et de l'interaction de l'utilisateur.

Je me suis fixé une ligne directrice pour moi d'utiliser le BFExecutor lié à la série dispatch_queue_t quand toucher quoi que ce soit relatifs au service, pour la sécurité des threads.

Pointant du doigt d'autres meilleures pratiques serait utile, merci!

#import <Bolts/Bolts.h>
dispatch_queue_t serialQueue;
BFExecutor *serialExecutor;
BFTask *maintask;
int32_t key = 0;
BOOL initialized = FALSE;
@implementation yAppDelegate
- (void)setKey:(int32_t)key_ {
//Don't worry about success, just appending to outstanding tasks
maintask = [maintask continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
key = key_;
NSLog(@"set key to %d", key);
[source setResult:nil];
if (initialized) {
[self initialize];
}
return source.task;
}];
}
- (BFTask *)downloadConfig {
BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
dispatch_async(serialQueue, ^{
NSLog(@"working on init config, key = %d...", key);
//Trigger from a different queue
double delayInSeconds = 1.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[source setResult:nil];
});
});
return source.task;
}
- (BFTask *)initializeService {
BFTaskCompletionSource *source = [BFTaskCompletionSource taskCompletionSource];
dispatch_async(serialQueue, ^{
NSLog(@"working on init service, key = %d...", key);
//Trigger from a different queue
double delayInSeconds = 1.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[source setResult:nil];
});
//Set final state
initialized = TRUE;
});
return source.task;
}
- (void)initialize {
int32_t oldKey = key;
__block bool reinit = false;
//Start by chaining it to whatever task is in flight without regard to success
//Everything should use the serialQueue or serialExecutor for thread safety
maintask = [[[maintask continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
if (oldKey != key) {
NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
reinit = true;
return [BFTask cancelledTask];
}
return [self downloadConfig];
}] continueWithExecutor:serialExecutor withSuccessBlock:^id(BFTask *task) {
if (oldKey != key) {
NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
reinit = true;
return [BFTask cancelledTask];
}
return [self initializeService];
}] continueWithExecutor:serialExecutor withBlock:^id(BFTask *task) {
if (oldKey != key) {
NSLog(@"key out of date (%d != %d).  reinitializing...", oldKey, key);
reinit = true;
}
if (task.error || task.exception || task.isCancelled) {
if (reinit) {
[self initialize];
}
return nil;
} else {
NSLog(@"initService completed = %d", key);
return nil;
}
}];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
serialQueue = dispatch_queue_create("serial", NULL);
serialExecutor = [BFExecutor executorWithDispatchQueue:serialQueue];
//Start with an empty task so all tasks can be strung together without need to initialize
maintask = [BFTask taskWithResult:nil];
//Everything related to changing service state should be contained with the serialQueue dispatch queue
[self setKey:1];
[self initialize];
[self setKey:2];
[self setKey:3];
dispatch_async(dispatch_get_main_queue(), ^(void){
[self setKey:4];
});
dispatch_async(serialQueue, ^(void){
[self setKey:5];
});
[self setKey:6];
//Override point for customization after application launch.
return YES;
}
@end

Les résultats sont comme prévu. L'initialisation est essayé avec la touche = 1, mais est différée jusqu'à ce qu'il cesse de changer. Le service est ensuite initialisé sur sa file d'attente avec la clé = 5, puis ré-initialisé avec la clé = 4.

Résultats:

set key to 1
key out of date (0 != 1).  reinitializing...
key out of date (0 != 1).  reinitializing...
set key to 2
set key to 3
set key to 6
set key to 5
key out of date (1 != 5).  reinitializing...
key out of date (1 != 5).  reinitializing...
working on init config, key = 5...
working on init service, key = 5...
initService completed = 5
set key to 4
working on init config, key = 4...
working on init service, key = 4...
initService completed = 4

OriginalL'auteur Shawn