Object serialization: Difference between revisions

Line 1,124:

int numberOfLegs;

}

- (id) initWithName: (NSString*)name andLegs: (NSInteger)legs;

- (instancetype) initWithName: (NSString*)name andLegs: (NSInteger)legs;

- (void) dump;

// the following allows "(de)archiving" of the object

- (void) encodeWithCoder: (NSCoder*)coder;

- (id) initWithCoder: (NSCoder*)coder;

@end

@implementation Animal

- (id) initWithName: (NSString*)name andLegs: (NSInteger)legs

- (instancetype) initWithName: (NSString*)name andLegs: (NSInteger)legs

{

if ((self = [super init])) {

Line 1,139:

Line 1,136:

}

return self;

}

- (void) dealloc

{

[animalName release];

[super dealloc];

}

- (void) dump

Line 1,170:

Line 1,162:

NSMutableArray *eatenList;

}

- (id) initWithName: (NSString*)name hasFur: (BOOL)fur;

- (instancetype) initWithName: (NSString*)name hasFur: (BOOL)fur;

- (void) addEatenThing: (NSString*)thing;

- (void) dump;

// for archiving / dearchiving:

- (void) encodeWithCoder: (NSCoder*)coder;

- (id) initWithCoder: (NSCoder*)coder;

@end

@implementation Mammal

- (id) init

- (instancetype) init

{

if ((self = [super init])) {

Line 1,187:

Line 1,175:

return self;

}

- (id) initWithName: (NSString*)name hasFur: (BOOL)fur

- (instancetype) initWithName: (NSString*)name hasFur: (BOOL)fur

{

if ((self = [super initWithName: name andLegs: 4])) {

Line 1,198:

Line 1,186:

{

[eatenList addObject: thing];

}

- (void) dealloc

{

[eatenList release];

[super dealloc];

}

- (void) dump

Line 1,208:

Line 1,191:

[super dump];

NSLog(@"has fur? %@", (hasFur) ? @"yes" : @"no" );

// fast enum not implemented yet in gcc 4.3, at least

// without a patch that it seems to exist...

NSEnumerator *en = [eatenList objectEnumerator];

id element;

NSLog(@"it has eaten %d things:", [eatenList count]);

for ( id element in eatenList )

while( (element = [en nextObject]) != nil )

NSLog(@"it has eaten a %@", element);

NSLog(@"end of eaten things list");

Line 1,228:

Line 1,207:

if ((self = [super initWithCoder: coder])) {

hasFur = [coder decodeBoolForKey: @"Mammal.hasFur"];

eatenList = [[coder decodeObjectForKey: @"Mammal.eaten"~~] retain~~];

eatenList = [coder decodeObjectForKey: @"Mammal.eaten"];

}

return self;

Line 1,237:

Line 1,216:

int main()

{

@autoreleasepool {

Mammal *aMammal;

Animal *anAnimal;

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

// let us create a fantasy animal

anAnimal = [[Animal alloc]

Animal *anAnimal = [[Animal alloc]

initWithName: @"Eptohippos"

andLegs: 7

];

// for some reason an Eptohippos is not an horse with 7 legs,

// and it is not a mammal, of course...

// let us create a fantasy mammal (which is an animal too)

aMammal = [[Mammal alloc]

Mammal *aMammal = [[Mammal alloc]

initWithName: @"Mammaluc"

hasFur: YES

];

// let us add some eaten stuff...

[aMammal addEatenThing: @"lamb"];

[aMammal addEatenThing: @"table"];

[aMammal addEatenThing: @"web page"];

// dump anAnimal

NSLog(@"----- original Animal -----");

[anAnimal dump];

// dump aMammal...

NSLog(@"----- original Mammal -----");

[aMammal dump];

// now let us store the objects...

NSMutableData *data = [[NSMutableData alloc] init];

NSKeyedArchiver *arch = [[NSKeyedArchiver alloc]

initForWritingWithMutableData: data];

[arch encodeObject: anAnimal forKey: @"Eptohippos"];

[arch encodeObject: aMammal forKey: @"Mammaluc"];

⚫

[arch finishEncoding];

[anAnimal release];

⚫

[data writeToFile: @"objects.dat" atomically: YES];

[aMammal release];

⚫

[arch finishEncoding];

[arch release];

⚫

[data writeToFile: @"objects.dat" atomically: YES];

[data release];

// now we want to retrieve the saved objects...

NSData *ldata = [[NSData alloc]

initWithContentsOfFile: @"objects.dat"];

NSKeyedUnarchived *darch = [[NSKeyedUnarchiver alloc]

initForReadingWithData: ldata];

Animal *archivedAnimal = [darch decodeObjectForKey: @"Eptohippos"];

Mammal *archivedMammal = [darch decodeObjectForKey: @"Mammaluc"];

[darch finishDecoding];

[ldata release];

[darch release];

// now let's dump/print the objects...

NSLog(@"\n");

NSLog(@"----- the archived Animal -----");

[archivedAnimal dump];

NSLog(@"----- the archived Mammal -----");

[archivedMammal dump];

}

[pool release];

return EXIT_SUCCESS;

}</lang>