shapes.m

#import <Foundation/Foundation.h>

@interface Square : NSObject {
    NSNumber *width;
    NSNumber *height;
    CGPoint center;
}

- (id)initWithJSON:(NSDictionary *)jsonData;

@end

@implementation Square

- (id)initWithJSON:(NSDictionary *)jsonData {
	self = [super init];
	if (self != nil) {
		width = [jsonData objectForKey:@"width"];
		height = [jsonData objectForKey:@"height"];
		center.x = [[[jsonData objectForKey:@"center"] objectAtIndex:0] floatValue];
		center.y = [[[jsonData objectForKey:@"center"] objectAtIndex:1] floatValue];

	}
	return self;
}

- (NSString *)description {
	return [NSString stringWithFormat:
			@"I am square with width %d, height %d, and center %f,%f", 
			[width intValue], [height intValue], center.x, center.y];
}

@end

@interface Circle : NSObject {
    NSNumber *radius;
    CGPoint center;
}

- (id)initWithJSON:(NSDictionary *)jsonData;

@end

@implementation Circle

- (id)initWithJSON:(NSDictionary *)jsonData {
	self = [super init];
	if (self != nil) {
		radius = [jsonData objectForKey:@"radius"];
		center.x = [[[jsonData objectForKey:@"center"] objectAtIndex:0] floatValue];
		center.y = [[[jsonData objectForKey:@"center"] objectAtIndex:1] floatValue];
	}
	return self;
}

- (NSString *)description {
	return [NSString stringWithFormat:
			@"I am circle with radius %d, and center %f,%f", 
			[radius intValue], center.x, center.y];
}


@end

@interface ResponseHandler : NSObject {
	NSArray *dataObjs;
}

@property (nonatomic, retain)NSArray *dataObjs;

- (id)initWithShapesData:(NSDictionary *)jsonData;

@end

@implementation ResponseHandler

@synthesize dataObjs;

- (id)initWithShapesData:(NSDictionary *)jsonData {
	self = [super init];
	if (self != nil) {
		NSDictionary *classMap = [NSDictionary dictionaryWithObjectsAndKeys:
								  [Square class], @"SquareObject", [Circle class], @"CircleObject", nil];
		NSMutableArray *tmpObjs = [[NSMutableArray alloc] init];
		NSObject *anObj;
		for (NSString *aKey in [classMap allKeys]) {
			anObj = [[[classMap objectForKey:aKey] alloc] initWithJSON:[jsonData objectForKey:aKey]];
			[tmpObjs addObject:anObj];
			[anObj release];
		}
		self.dataObjs = [NSArray arrayWithArray:tmpObjs];
		[tmpObjs release];
	}
	return self;
}

@end

NSDictionary *mockJSONData(){
	//Pretend the original JSON dictionary was previously converted to an NSDictionary for us with TouchJSON
	//Original JSON was: "{'SquareObject': {'width': 10, 'height':10, 'center':[5,5]}, 'CircleObject': {'radius':10, 'center':[2,2]}}"
	NSArray *squareCenter = [NSArray arrayWithObjects:[NSNumber numberWithInt:5],[NSNumber numberWithInt:5], nil];
	NSArray *circleCenter = [NSArray arrayWithObjects:[NSNumber numberWithInt:2],[NSNumber numberWithInt:2], nil];
	NSDictionary *sqr = [NSDictionary dictionaryWithObjectsAndKeys:
						 [NSNumber numberWithInt:10], @"width", [NSNumber numberWithInt:10], @"height", squareCenter, @"center", nil];
	NSDictionary *cir = [NSDictionary dictionaryWithObjectsAndKeys:
						 [NSNumber numberWithInt:10], @"radius", circleCenter, @"center", nil];
	//jsonData is the object we would have received from TouchJSON
	NSDictionary *jsonData = [NSDictionary dictionaryWithObjectsAndKeys:sqr, @"SquareObject", cir, @"CircleObject", nil];
	return jsonData;
}

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
	
	NSDictionary *shapesData = mockJSONData();

	ResponseHandler *response = [[ResponseHandler alloc] initWithShapesData:shapesData];
	for (NSObject *anObj in response.dataObjs) {
		NSLog(@"%@", anObj);
	}
	
	
    [pool drain];
    return 0;
}