Proxying in Objective-C

ProxyExample.m

@interface ChildClass : NSObject
- (NSInteger)read;
@end

// *.h
@interface MyDecorator : NSObject
+ (instancetype)decoratedInstanceOf:(ChildClass *)instance;
@end

// *.m
@interface MyDecorator()
@property (nonatomic, strong) ChildClass *instance;
@end

@implementation MyDecorator

+ (instancetype)decoratedInstanceOf:(ChildClass *)instance {
    return [[self alloc] initWithObject:instance];
}

- (instancetype)initWithObject:(ChildClass *)object {
    _instance = object;
    return self;
}

- (id)forwardingTargetForSelector:(SEL)aSelector {
    return self.instance;
}

- (NSInteger)read {
    return [self.instance read] + 1;
}

@end