NSCondition模擬買票的過程的簡單實現

@interface ViewController ()
@property (nonatomic, strong) NSMutableArray * array;
@property (nonatomic, strong) NSCondition * condition;
@property (nonatomic, strong) NSTimer * timer;
@end
@implementation ViewController
//初始化

(NSMutableArray *)array

{

if (!_array) {

    _array = [NSMutableArray array];

}

return _array;


}

(NSCondition *)condition

{

if (!_condition) {

    _condition = [[NSCondition alloc] init];

}

return  _condition;


}
//加載

(void)viewDidLoad {
[super viewDidLoad];



//購買

for (int i = 0; i<3; i++)

{

    [self performSelectorInBackground:@selector(_consumer) withObject:nil];

}



//生產

self.timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(_productor) userInfo:nil repeats:YES];




}

(void)_productor

{

[self.condition lock];



if (self.array.count != 0)

{

    NSLog(@"結束");

    [self.timer invalidate];

    self.timer = nil;

}

else

{

    [self.array addObject:@"aaa"];

    NSLog(@"生產完成！");

    [self.condition signal];

}



[self.condition unlock];






}

(void)_consumer

{

[self.condition lock];



if (self.array.count <= 0)

{

    NSLog(@"正在等待！");

    [self.condition wait];

}



[self.array removeLastObject];

NSLog(@"購買成功！");



[self.condition unlock];


}
@end
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