Question

Please refer to the following code:

 //
//  CacheObjectManagerImpl.h

#import <Foundation/Foundation.h>
//#import "CacheObject.h"

@class CacheObject;

@protocol ICacheObjectManager <NSObject>

typedef enum {
    kSTRING,
    kBYTEARRAY,
    kCACHABLE,
    kSTRINGVALUE
} CacheObjType;

CacheObjType *CacheObjectType;

@required
//- (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url 
- (CacheObject *) createCacheObject:(NSString *)data url:(BOOL*)isURL savefile:(BOOL*)saveToFile downloadmgr:(ICacheObjDownloadMgr*) downloadMgr;
//-(CacheObject*) createCacheObject: (Cachable*) dataObject;
@end


@interface CacheObjectManagerImpl : NSObject {

}

@property(nonatomic,assign) id <ICacheObjectManager> delegate;

@end

The next file which uses the above class CacheObject:

//
//  CacheManagerImpl.h

#import <Foundation/Foundation.h>
//#import "CacheObject.h"
//#import "CacheObjectManagerImpl.h"


@class CacheObject;
@class CacheObjectManagerImpl;


@protocol ICachePurgeLogic <NSObject>

@required

- (void)runPurge: (NSDictionary*)cacheMap;

@end


@protocol ICacheManager <NSObject>

@required
- (void) put:(NSString*)key cacheobj:(CacheObject*)cacheObj;
- (CacheObject*)get: (NSString*)key;
- (void) clearEntireCache;
- (void) remove: (NSString*)key;
- (void) purge;
- (void) setCachePurgeCustomMgr: (ICachePurgeLogic*)cachePurgeLogic; **//ERROR: error: expected ')' before 'ICachePurgeLogic'**

@end

@interface CacheManagerImpl : NSObject {

    NSNumber *timeToLive;
    NSDictionary *cacheMap;
    ICacheObjectManager *cacheObjMgr; **//ERROR: error: expected specifier-qualifier-list before 'ICacheObjectManager'**

    ICachePurgeLogic *purgeManager; **//ERROR: error: expected specifier-qualifier-list before 'ICachePurgeLogic'**

}

@property(nonatomic,assign) id <ICacheManager> delegate;

- (void) getCacheManagerInstance: (NSNumber*) timeToLive;
- (ICacheObjectManager*) createCacheObjManager; **//ERROR: error: expected ')' before 'ICacheObjectManager'**

- (ICacheObjectManager*) getCacheObjManager; **//ERROR: error: expected ')' before 'ICacheObjectManager'**

@end

I am unable to understand why I am getting the above errors. If I include the header files, I get more errors due cyclical header includes. What are the possible work arounds for these compiler errors? Or my code is entirely wrong in the sense that I am passing and returning by protocols.

Thanks,

Answer 1

I would start by moving your enum declaration and what appears to be an ivar that is a pointer to your declared type out of your protocol. You shouldn’t be declaring types within a protocol declaration. Additionally, if you want to require the classes implementing your protocol to have an object of a certain type, declare a property. Protocols only specify methods that should or need to be implemented.