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PONSMutableArray collection and @Synchronized blocks
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  1. PONSMutableArray collection and @Synchronized blocks
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    copied!<p>In Objective C I'm using a NSMutableArray instance from various thread and I'm using @synchronized to make it thread safe. currently all my acces to this array are protected with a @synchronized block, even objectAtIndex: method. Nevertheless I wonder which methods call really need to be protected with @synchronized. do I need to protect read access ?</p> <p>What would happens if 'ObjectAtIndex' is not protected and called at the same time that 'removeObject' ? </p> <p>If all methods are protected by a @synchronized what about performance? (I'writing a tcp/udp game server and really don't want to overprotect these array if it would decrease perf or generate locks). </p> <p>for example I suppose that the 'containsObject:' method will enumerate to find the object and that I should avoid a concurent call to 'removeObject:' in another thread.</p> <p>Perhaps a good solution would be to have too different locks (for read and write access)...</p> <p>Help and suggestion are welcome !</p> <p>Thanks a lot.</p> <p>Please find a sample code below to illustrate :</p> <pre><code>@interface TestClass : NSObject { NSMutableArray * array; } @end @implementation TestClass - (id)init { self = [super init]; if (self) { array = [NSMutableArray array]; } return self; } -(id)objectAtIndex:(NSUInteger)index { @synchronized(array) **// IS IT USEFUL OR NOT ??** { return [array objectAtIndex:index]; } } -(void)removeObject:(id)object { @synchronized(array) { [array removeObject:object]; } } -(void)compute { @synchronized(array) { for (id object in array) { [object compute]; } } } @end </code></pre>
 

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