iOS 单例模式

#import <Foundation/Foundation.h>

@interface Singleton :NSObject

+ (Singleton *)sharedSingleton;

+ (void)purgeSharedSingleton;

@end

#import "Singleton.h"

@implementation Singleton

staticSingleton* sInstance = nil;

+ (Singleton *)sharedSingleton

{

    @synchronized(self) {

        if (sInstance == nil) {

            [[selfalloc] init];

        }

    }

    returnsInstance;

}

+ (void)purgeSharedSingleton

{

    if (sInstance) {

        [sInstancerealRelease];

    }

}

+ (id)allocWithZone:(struct_NSZone *)zone

{

    @synchronized(self) {

        if (sInstance == nil) {

            sInstance = [superallocWithZone:zone];

            return sInstance;

        }

    }

    returnsInstance;

}

+ (id)copyWithZone:(struct_NSZone *)zone

{

    returnself;

}

- (id)copy

{

    returnself;

}

- (id)retain

{

    returnself;

}

- (NSUInteger)retainCount

{

    return UINT_MAX;

}

- (onewayvoid)release

{

    

}

- (id)autorelease

{

    returnself;

}

- (void)dealloc

{

    sInstance = nil;

    [superdealloc];

}

- (void)realRelease

{

    [superrelease];

}

@end