OC7_复合类内存管理(setter方法)

//
//  Person.h
//  OC7_复合类内存管理(setter方法)
//
//  Created by zhangxueming on 15/6/18.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//#import <Foundation/Foundation.h>
#import "Dog.h"@interface Person : NSObject
{
    Dog *_dog;
}- (Dog *)dog;- (void)setDog:(Dog *)dog;@end

//
//  Person.m
//  OC7_复合类内存管理(setter方法)
//
//  Created by zhangxueming on 15/6/18.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//#import "Person.h"@implementation Person- (Dog *)dog
{
    return _dog;
}//方法一:
//- (void)setDog:(Dog *)dog
//{
//    _dog = dog;
//}//方法二://- (void)setDog:(Dog *)dog
//{
//    _dog = [dog retain];
//}//方法三:- (void)setDog:(Dog *)dog//xiaoHei _dog count = 1;
{
    [_dog release];//0
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
//    NSLog(@"lajfalfjal");
//    NSLog(@"jslfjslfjl");
    _dog = [dog retain];
}//标准写法
//- (void)setDog:(Dog *)dog
//{
//    if (_dog!=dog) {
//        [_dog release];
//        _dog = [dog retain];
//    }
//}- (void)dealloc
{
    [_dog release];
    [super dealloc];
}@end

//
//  Dog.h
//  OC7_复合类内存管理(setter方法)
//
//  Created by zhangxueming on 15/6/18.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//#import <Foundation/Foundation.h>@interface Dog : NSObject@end

//
//  Dog.m
//  OC7_复合类内存管理(setter方法)
//
//  Created by zhangxueming on 15/6/18.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//#import "Dog.h"@implementation Dog
//-(void)dealloc
//{
//    //NSLog(@"12321313");
//    [super dealloc];
//}
@end

//
//  main.m
//  OC7_复合类内存管理(setter方法)
//
//  Created by zhangxueming on 15/6/18.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//#import <Foundation/Foundation.h>
#import "Dog.h"
#import "Person.h"int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Dog *xiaoBai = [[Dog alloc] init];
        Person *xiaoXin = [[Person alloc] init];
        //方法一: 不ok，人并没有真正持有狗，如果在main函数里[xiaoBai release]，让dog的引用计数减1，就变为0，dog就销毁了
//        xiaoXin.dog = xiaoBai;
//        NSLog(@"retainCount = %li", xiaoBai.retainCount);
//         [xiaoBai release];//
       // [xiaoXin release];
        //方法二:
        //不ok，如果人再持有别的狗，就会造成第一条狗得不到释放，内存泄露。
//        xiaoXin.dog = xiaoBai;
//        NSLog(@"xiaoBai retainCount = %li", xiaoBai.retainCount);
//        Dog *xiaoHei = [[Dog alloc] init];
//        xiaoXin.dog = xiaoHei;
//        [xiaoBai release];
//        [xiaoHei release];
//        [xiaoXin release];
        //方法三:不ok，如果本来持有一条狗，又重新设置这条狗，先进行release，这个时候，很可能dog就销毁了，然后，就没法再次retain了。
        xiaoXin.dog = xiaoBai;
        Dog *xiaoHei = xiaoBai;   //[xiaoBai retain]
         NSLog(@"xiaoHei retainCount = %li", xiaoBai.retainCount);
        [xiaoBai release];
       NSLog(@"xiaoHei retainCount = %li", xiaoHei.retainCount);
       xiaoXin.dog = xiaoHei;
        [xiaoXin release];    }
    return ;
}