详解iOS App设计模式开发中对于享元模式的运用

#import <Foundation/Foundation.h>
#import "WebSiteProtocol.h"
@interface WebSiteFactory : NSObject
 
@property (nonatomic, strong) NSDictionary *flyweights; //共享对象
 
- (id<WebSiteProtocol>)getWebSiteCategory:(NSString *)webKey;
- (NSInteger)getWebSiteCount;
 
@end

#import "WebSiteFactory.h"
#import "ConcreteWebSite.h"
@implementation WebSiteFactory
 
- (instancetype)init {
    self = [super init];
    if (self) {
        _flyweights = [NSDictionary dictionary];
    }
    return self;
}
 
- (id<WebSiteProtocol>)getWebSiteCategory:(NSString *)webKey {   
    __block id<WebSiteProtocol> webset = nil;
    [self.flyweights enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        if (webKey == key) {
            webset = obj;
            *stop = YES;
        }
    }];
    
    if (webset == nil) {
        ConcreteWebSite *concreteWebset = [[ConcreteWebSite alloc] init];
        concreteWebset.webName = webKey;
        webset = concreteWebset;
        
        NSMutableDictionary *mutabledic = [NSMutableDictionary dictionaryWithDictionary:self.flyweights];
        [mutabledic setObject:webset forKey:webKey];
        self.flyweights = [NSDictionary dictionaryWithDictionary:mutabledic];
    }
    
    return webset;
}
 
- (NSInteger)getWebSiteCount {
    return self.flyweights.count;
}
 
@end

#import <Foundation/Foundation.h>
#import "User.h"
@protocol WebSiteProtocol <NSObject>
 
- (void)use:(User *)user;
 
@end

#import <Foundation/Foundation.h>
#import "WebSiteProtocol.h"
@interface ConcreteWebSite : NSObject <WebSiteProtocol>
 
@property (nonatomic, copy) NSString *webName;
 
@end

#import "ConcreteWebSite.h"
 
@implementation ConcreteWebSite
 
- (void)use:(User *)user {
    NSLog(@"网站分类:%@ 用户名字:%@", self.webName, user.userName);
}
 
@end

#import <Foundation/Foundation.h>
 
@interface User : NSObject
 
@property (nonatomic, copy) NSString *userName;
 
@end

#import "User.h"
 
@implementation User
 
@end

#import "ViewController.h"
#import "WebSiteProtocol.h"
#import "WebSiteFactory.h"
#import "ConcreteWebSite.h"
#import "User.h"
typedef id<WebSiteProtocol> WebsiteType;
@interface ViewController ()
 
@end

@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    // 通过工厂方法返回各种具体享元对象,维护池中的享元对象
    WebSiteFactory *factory = [[WebSiteFactory alloc] init];
    
    // 返回具体的享元对象
    WebsiteType type1 = [factory getWebSiteCategory:@"首页"];
    User *user1 = [[User alloc] init];
    user1.userName = @"张三";
    // 享元对象都具有use方法
    [type1 use:user1];
    
    WebsiteType type2 = [factory getWebSiteCategory:@"商店"];
    User *user2 = [[User alloc] init];
    user2.userName = @"李四";
    [type2 use:user2];
    
    WebsiteType type3 = [factory getWebSiteCategory:@"案例"];
    User *user3 = [[User alloc] init];
    user3.userName = @"王五";
    [type3 use:user3];
    
    NSInteger count = [factory getWebSiteCount];
    NSLog(@"个数: %ld", (long)count);
    
}
 
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
 
@end

2015-09-12 15:59:55.322 FlyweightPattern[42020:1723017] 网站分类:首页 用户名字:张三
2015-09-12 15:59:55.322 FlyweightPattern[42020:1723017] 网站分类:商店 用户名字:李四
2015-09-12 15:59:55.322 FlyweightPattern[42020:1723017] 网站分类:案例 用户名字:王五
2015-09-12 15:59:55.323 FlyweightPattern[42020:1723017] 个数: 3