#import "UserCenter.h"
@interface UserCenter()
{
// 定義一個并發(fā)隊列
dispatch_queue_t concurrent_queue;
// 用戶數(shù)據(jù)中心, 可能多個線程需要數(shù)據(jù)訪問
NSMutableDictionary *userCenterDic;
}
@end
// 多讀單寫模型
@implementation UserCenter
- (id)init
{
self = [super init];
if (self) {
// 通過宏定義 DISPATCH_QUEUE_CONCURRENT 創(chuàng)建一個并發(fā)隊列
concurrent_queue = dispatch_queue_create("read_write_queue", DISPATCH_QUEUE_CONCURRENT);
// 創(chuàng)建數(shù)據(jù)容器
userCenterDic = [NSMutableDictionary dictionary];
}
return self;
}
- (id)objectForKey:(NSString *)key
{
__block id obj;
// 同步讀取指定數(shù)據(jù)
dispatch_sync(concurrent_queue, ^{
obj = [userCenterDic objectForKey:key];
});
return obj;
}
- (void)setObject:(id)obj forKey:(NSString *)key
{
// 異步柵欄調(diào)用設(shè)置數(shù)據(jù)
dispatch_barrier_async(concurrent_queue, ^{
[userCenterDic setObject:obj forKey:key];
});
}
@end
dispatch_barrier_async:
- Submits a barrier block for asynchronous execution and returns immediately.
dispatch_sync：
- Submits a block object for execution and returns after that block finishes executing.
