Singleton: Difference between revisions
Content added Content deleted
(Add Racket example) |
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} |
} |
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+ (SomeSingleton*)sharedInstance; |
+ (SomeSingleton *)sharedInstance; |
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@end</lang> |
@end</lang> |
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@implementation SomeSingleton |
@implementation SomeSingleton |
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+ (SomeSingleton*) sharedInstance |
+ (SomeSingleton *) sharedInstance |
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{ |
{ |
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static sharedInstance = nil; |
static SomeSingleton *sharedInstance = nil; |
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if(!sharedInstance) { |
if (!sharedInstance) { |
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sharedInstance = [[SomeSingleton alloc] init]; |
sharedInstance = [[SomeSingleton alloc] init]; |
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} |
} |
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} |
} |
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- (void)release |
- (oneway void)release |
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{ |
{ |
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// prevent release |
// prevent release |
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@end</lang> |
@end</lang> |
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===Thread-Safe=== |
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Same as above except: |
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<lang objc>+ (SomeSingleton *) sharedInstance |
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{ |
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static SomeSingleton *sharedInstance = nil; |
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@synchronized(self) { |
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if (!sharedInstance) { |
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sharedInstance = [[SomeSingleton alloc] init]; |
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} |
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} |
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return sharedInstance; |
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}</lang> |
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===With GCD=== |
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Same as above except: |
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<lang objc>+ (SomeSingleton *) sharedInstance |
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{ |
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static SomeSingleton *sharedInstance = nil; |
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static dispatch_once_t onceToken; |
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dispatch_once(&onceToken, ^{ |
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sharedInstance = [[SomeSingleton alloc] init]; |
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}); |
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return sharedInstance; |
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}</lang> |
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=={{header|ooRexx}}== |
=={{header|ooRexx}}== |
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