Swift调用Objective-C协议readonly属性

Question

我有像这样的Objective-C协议：

@protocol OBJCDelegate <NSObject> 
@property (nonatomic, copy, readonly) NSString *info;
- (void)setInfo:(NSString *)info;
@end

@interface OBJCObject: NSObject <OBJCDelegate>
@end

  

Objective-C代码来自第三方库，我无权修改它。

然后我使用swift2.0调用objective-c：

let objcObject = OBJCObject()
objcObject.setInfo("info") // error on this line, error is : Value of type 'OBJCObject' has no member 'setInfo'

swift找不到setInfo函数，为什么？