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POWhat is a good approach to set init configurables variables on singleton classes in Objective-c?
 

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  1. POWhat is a good approach to set init configurables variables on singleton classes in Objective-c?
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    <p>Nomaly I used to build a singleton the following recipe:</p> <pre><code>+ (MyClass *)sharedInstance { static MyClass *_sharedInstance = nil; static dispatch_once_t oncePredicate; dispatch_once(&amp;oncePredicate, ^{ _sharedInstance = [[self alloc] init]; // Init variables }); return _sharedInstance; } </code></pre> <p>Then I can call methods as following:</p> <pre><code>[[MyClass sharedInstance] anyInstanceMethod]; </code></pre> <p>But, what happen when any init variables are configurables from outside the class? My approach is create two class methods, one of them with configurables variables:</p> <pre><code>+ (MyClass *)sharedInstanceWithVariableOne:(NSString*)aParamOne andVariableTwo:(NSString*)aParamTwo { static MyClass *_sharedInstance = nil; static dispatch_once_t oncePredicate; dispatch_once(&amp;oncePredicate, ^{ _sharedInstance = [[self alloc] init]; // Init configurables variables _sharedInstance.paramOne = aParamOne; _sharedInstance.paramTwo = aParamTwo; }); return _sharedInstance; } </code></pre> <p>And the second one as proxy to this last one with default values:</p> <pre><code> + (MyClass *)sharedInstance { return [MyClass sharedInstanceWithVariableOne:@"value1" andVariableTwo:@"value2"]; } </code></pre> <p>So, if you want to use singleton class with configure variables, you should call first of all <code>sharedInstanceWithVariableOne:andVariableTwo</code> and then only <code>sharedInstance</code>. I think this approach is not the best and I'm looking forward to use others.</p> <p>Thanks in advance.</p>
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    1. USmartinezdelariva
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    1. COWhy you dont like this?
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    2. COI find this pattern a bit fishy. Consider what happens when calling `sharedInstanceWithVariableOne:...` multiple times. Only the first set of parameters would have any effect, the other ones would get the same shared instance, but not with the expected parameters. Either each configuration should be a separate object, or these parameters should be properties of the shared instance that are just set whenever you need to change them.
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    3. COAnoop Vaidya, I think that could exist a better approach. This one could be confused and not obvious for use.
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      1. USmartinezdelariva
 

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