objc-singleton

FJCSingleton.h

//
//  FJCSingleton.h
//  Singleton
//
//  Created by Flávio Caetano on 2/6/14.
//  Copyright (c) 2014 flaviocaetano.com. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface FJCSingleton : NSObject

+ (instancetype)sharedInstance;

@end

FJCSingleton.m

//
//  FJCSingleton.m
//  Singleton
//
//  Created by Flávio Caetano on 2/6/14.
//  Copyright (c) 2014 flaviocaetano.com. All rights reserved.
//

#import "FJCSingleton.h"

@interface FJCSingleton()

- (instancetype)initSuper;

@end

@implementation FJCSingleton

- (id)init
{
    [NSException raise:@"Singleton Class" format:@"You must use [%@ sharedInstance] instead", NSStringFromClass(self.class)];
    return nil;
}

- (instancetype)initSuper
{
    if(self = [super init])
    {
        <#Init Code#>
    }
    
    return self;
}

+(instancetype)sharedInstance
{
    __block FJCSingleton *sharedInstance;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[FJCSingleton alloc] initSuper];
    });
    
    return sharedInstance;
}

@end