问NSKeyedArchiver的问题

EN

#import <Foundation/Foundation.h>

#import "JFIdentifier.h" // This is my own class to create a unique identifier for every JKDataObject


@interface JKDataObject : NSObject <NSCoding> {
    NSUInteger identifier;
    NSString *user;
    NSDate *creationDate;
    NSDate *alteredDate;    
}
#pragma mark -

#pragma mark Setter
- (void)setIdentifier:(NSUInteger)newIdentifier silent:(BOOL)silent;
- (void)setUser:(NSString *)newUser silent:(BOOL)silent;
- (void)setCreationDate:(NSDate *)newCreationDate silent:(BOOL)silent;
- (void)setAlteredDate:(NSDate *)newAlteredDate;
#pragma mark -

#pragma mark Getter
- (NSUInteger)identifier;
- (NSString *)user;
- (NSDate *)creationDate;
- (NSDate *)alteredDate;
#pragma mark -

#pragma mark Methods
- (void)dataObjectWasAltered:(JKDataObject *)alteredObject;
#pragma mark -

@end

#import "JKDataObject.h"


@implementation JKDataObject
#pragma mark -

#pragma mark Initiation
- (id)init {
    [super init];

    identifier = [JFIdentifier createIdentifier];

    user = [[NSString alloc] initWithString:NSUserName()];

    creationDate = [[NSDate alloc] initWithTimeIntervalSinceNow:0];
    alteredDate = [[NSDate alloc] initWithTimeIntervalSinceNow:0];;

    return self;
}
- (id)initWithCoder:(NSCoder *)decoder {
    [super init];

    identifier = [decoder decodeIntegerForKey:@"identifier"];
    user = [[decoder decodeObjectForKey:@"user"] retain];
    creationDate = [[decoder decodeObjectForKey:@"creationDate"] retain];
    alteredDate = [[decoder decodeObjectForKey:@"alteredDate"] retain];

    return self;
}
- (void)encodeWithCoder:(NSCoder *)encoder {
//  [super encodeWithCoder:encoder];

    [encoder encodeInteger:identifier forKey:@"identifier"];
    [encoder encodeObject:user forKey:@"user"];
    [encoder encodeObject:creationDate forKey:@"creationDate"];
    [encoder encodeObject:alteredDate forKey:@"alteredDate"];
}

- (void)release {
    [user release];
    [creationDate release];
    [alteredDate release];

    [super release];
}
#pragma mark -

#pragma mark Setter
- (void)setIdentifier:(NSUInteger)newIdentifier silent:(BOOL)silent {
    identifier = newIdentifier;

    if (!silent) {
        [self dataObjectWasAltered:self];
    }
}
- (void)setUser:(NSString *)newUser silent:(BOOL)silent {
    user = newUser;

    if (!silent) {
        [self dataObjectWasAltered:self];
    }
}
- (void)setCreationDate:(NSDate *)newCreationDate silent:(BOOL)silent {
    creationDate = newCreationDate;

    if (!silent) {
        [self dataObjectWasAltered:self];
    }
}
- (void)setAlteredDate:(NSDate *)newAlteredDate {
    alteredDate = newAlteredDate;
}
#pragma mark -

#pragma mark Getter
- (NSUInteger)identifier {
    return identifier;
}
- (NSString *)user {
    return user;
}
- (NSDate *)creationDate {
    return creationDate;
}
- (NSDate *)alteredDate {
    return alteredDate;
}
#pragma mark -

#pragma mark Methods
- (void)dataObjectWasAltered:(JKDataObject *)alteredObject {
    alteredDate = [[NSDate alloc] initWithTimeIntervalSinceNow:0];
}
#pragma mark -

@end