NSCoder+KeyedSubscripting

gistfile1.m

// NSCoder+KeyedSubscripting.h:

@interface NSCoder (KeyedSubscripting)

- (id)objectForKeyedSubscript:(id <NSCopying>)key;
- (void)setObject:(id)object forKeyedSubscript:(id <NSCopying>)key;

@end


@interface NSKeyedArchiver (KeyedSubscripting)

- (void)setObject:(id)object forKeyedSubscript:(id<NSCopying>)key;

@end


@interface NSKeyedUnarchiver (KeyedSubscripting)

- (id)objectForKeyedSubscript:(id<NSCopying>)key;

@end

// NSCoder+KeyedSubscripting.m:

@implementation NSCoder (KeyedSubscripting)

- (id)objectForKeyedSubscript:(id<NSCopying>)key
{
    return nil; // Handled by subclass
}

- (void)setObject:(id)object forKeyedSubscript:(id<NSCopying>)key
{
    // Handled by subclass
}

@end


@implementation NSKeyedArchiver (KeyedSubscripting)

- (id)objectForKeyedSubscript:(id<NSCopying>)key
{
    @throw [NSException exceptionWithName:@"USLInvalidOperationException" reason:@"Cannot retrieve object from NSKeyedArchiver using subscripting" userInfo:nil];
}

- (void)setObject:(id)object forKeyedSubscript:(id<NSCopying>)key
{
    [self encodeObject:object forKey:(NSString *)key];
}

@end


@implementation NSKeyedUnarchiver (KeyedSubscripting)

- (id)objectForKeyedSubscript:(id<NSCopying>)key
{
    return [self decodeObjectForKey:(NSString *)key];
}

- (void)setObject:(id)object forKeyedSubscript:(id<NSCopying>)key
{
    @throw [NSException exceptionWithName:@"USLInvalidOperationException" reason:@"Cannot store object in NSKeyedUnarchiver using subscripting" userInfo:nil];
}

@end