제 4장. Objective C

객체 직렬화와 역직렬화

소스

//

//  main.m

//  demo192

//

//  Created by SDS107 on 12. 3. 29..

//  Copyright (c) 2012년 __MyCompanyName__. All rights reserved.

//

#import <Foundation/Foundation.h>

@interface Thingie : NSObject <NSCoding>

{

    NSString *name;

    int magicNumber;

    float shoeSize;

    NSMutableArray *subThingies;

}

@property (copy)NSString *name;

@property int magicNumber;

@property float shoeSize;

@property (retain)NSMutableArray *subThingies;

-(id)initWithName:(NSString *)n magicNumber:(int) mn shoeSize:(float)ss;

@end

@implementation Thingie

@synthesize name, magicNumber, shoeSize, subThingies;

-(id)initWithName:(NSString *)n magicNumber:(int)mn shoeSize:(float)ss

{

    if(self = [super init]){

        self.name = n;

        self.magicNumber = mn;

        self.shoeSize =ss;

        self.subThingies =[NSMutableArray array];

    }

    return self;

}

-(void)dealloc

{

    [name release];

    [subThingies release];

    [super dealloc];

}

-(void)encodeWithCoder:(NSCoder *)aCoder

{

[aCoder encodeObject:name forKey:@"name"];

[aCoder encodeInt:magicNumber forKey:@"magicNumber"];

[aCoder encodeFloat:shoeSize forKey:@"shoeSize"];

[aCoder encodeObject:subThingies forKey:@"subThingies"];

}

-(id)initWithCoder:(NSCoder *)aDecoder

{

if(self = [super init]){

    self.name = [aDecoder decodeObjectForKey:@"name"];

    self.magicNumber = [aDecoder decodeIntForKey:@"magicNumber"];

    self.shoeSize = [aDecoder decodeFloatForKey:@"shoeSize"];

    self.subThingies = [aDecoder decodeObjectForKey:@"subThingies"];

}

return self;

}

-(NSString*)description{

    NSString *description =

     [NSString stringWithFormat:@"%@: %d/%.1f %@",

      name, magicNumber, shoeSize, subThingies ];

return (description);

}

@end

int main(int argc, const char * argv[])

{

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

    

    Thingie *thing1;

    thing1 = [[Thingie alloc] initWithName:@"thing1" magicNumber:42 shoeSize:10];

    

    NSLog(@"shome thing:%@", thing1);

    

    NSLog(@"직렬화한다.");

    NSData *freezeDried;

    freezeDried = [NSKeyedArchiver archivedDataWithRootObject:thing1];

    [thing1 release];

    

    // 다시 역직렬화 한다.

    NSLog(@"역직렬화한다.");

    thing1 = [NSKeyedUnarchiver unarchiveObjectWithData:freezeDried];

    

    // 하위객체도 포함한 경우

    Thingie *anotherThing;

    anotherThing = [[Thingie alloc] initWithName:@"thing2" magicNumber:20 shoeSize:13];

    [thing1.subThingies addObject:anotherThing];

    NSLog(@"thing with things:%@", thing1);

    freezeDried = [NSKeyedArchiver archivedDataWithRootObject:thing1];

    thing1 = [NSKeyedUnarchiver unarchiveObjectWithData:freezeDried];

    

    NSLog(@"다시 복구:%@",thing1);

    [pool release];

         

                

    return 0;

}

결과

2012-03-29 11:07:11.249 demo192[3966:403] shome thing:thing1: 42/10.0 (

)

2012-03-29 11:07:11.251 demo192[3966:403] 직렬화한다.

2012-03-29 11:07:11.253 demo192[3966:403] 역직렬화한다.

2012-03-29 11:07:11.253 demo192[3966:403] thing with things:thing1: 42/10.0 (

    "thing2: 20/13.0 (\n)"

)

2012-03-29 11:07:11.254 demo192[3966:403] 다시 복구:thing1: 42/10.0 (

    "thing2: 20/13.0 (\n)"

)

키-벨류 코딩(KVC)

핵심 메서드 : -valueForKey: 와 setValue:forKey: valueForKeyPath 이다.

참고 소스

    //키밸류 코딩 소개 

    NSString *name = [car1 valueForKey:@"name"]; 

    NSLog(@"%@", name); 

    

    NSLog(@"make is %@", [car1 valueForKey:@"make"]); 

    NSLog(@"모델연식 %@", [car1 valueForKey:@"modelYear"]); 

    //이번에는 값을 지정해 본다. 

    [car1 setValue:@"Harold" forKey:@"name"];

    [car1 setValue:[NSNumber numberWithFloat:25062.4] forKey:@"mileage"]; 

     NSNumber *avgMileage;

     avgMileage = [garage valueForKeyPath: @"cars.@avg.mileage"];

     NSLog (@"average is %.2f", [avgMileage floatValue]);

NSPredicate

객체의 컬렉션이 어떤 값을 가지는지 검색하고 평가 할 경우 사용.

쓰임새는 마치 SQL문을 쓰는 것 처럼 보인다.

예제]

1) predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];

2) predicate = [NSPredicate predicateWithFormat:

@"(engine.horsepower > 50) AND (engine.horsepower < 200)"];