iOS设计模式 (十二)装饰者模式

概念

装饰模式是在不必改变原类文件和使用继承的情况下，动态地扩展一个对象的功能。它是通过创建一个包装对象，也就是装饰来包裹真实的对象.

UML

装饰模式.png

UML分析

Component(标准的装饰模式抽象类)，它声明了一些操作，它具体的类讲进行重载以实现自己特定的操作。这个Component具体类是模式中的被装饰者，Component父类可以被细化为另一个叫做Decorator的抽象类，即装饰者抽象类。Decorator类中包含了一个Component的引用。Decorator的具体类为Component或者Decorator定义了几个扩展行为，并且会在自己的操作中内嵌Component操作。

案例
*GameDecortor

#import 
#import "ComponentGame.h"

@interface GameDecortor : NSObject


//  上下左右
- (void)up;
- (void)down;
- (void)left;
- (void)right;

// 选择与开始的操作
- (void)select;
- (void)start;

// 按钮
- (void)commandA;
- (void)commandB;
- (void)commandC;
- (void)commandD;

@end

• CheatGameDecotor

#import "GameDecortor.h"

@interface CheatGameDecotor : GameDecortor


// 作弊器
- (void)cheat;

@end

#import "CheatGameDecotor.h"

@implementation CheatGameDecotor

- (void)cheat {
    // 作弊操作
    [self up];
    [self up];
    
    [self down];
    [self down];
    
    [self commandA];
    [self commandA];
}

@end

• ComponentGame

#import 

@interface ComponentGame : NSObject
//  上下左右
- (void)up;
- (void)down;
- (void)left;
- (void)right;

// 选择与开始的操作
- (void)select;
- (void)start;

// 按钮
- (void)commandA;
- (void)commandB;
- (void)commandC;
- (void)commandD;
@end
#import "GameDecortor.h"
#import "ComponentGame.h"

@interface GameDecortor ()

@property (nonatomic, strong)ComponentGame *game;

@end

@implementation GameDecortor

- (instancetype)init
{
    self = [super init ];
    if (self) {
        self.game = [ComponentGame new];
    }
    return self;
}

// GameLoL里面所有的方法
- (void)up {
    [self.game up];
}

- (void)down {
    [self.game down];
}

- (void)left {
    [self.game left];
}

- (void)right {
    [self.game right];
}

- (void)select {
    [self.game select];
}

- (void)start {
    [self.game start];
}

- (void)commandA {
    [self.game commandA];
}

- (void)commandB {
    [self.game commandB];
}

- (void)commandC
{
    [self.game commandC];
}

- (void)commandD
{
     [self.game commandD];
}

@end

*ComponentGame类

#import 

@interface ComponentGame : NSObject
//  上下左右
- (void)up;
- (void)down;
- (void)left;
- (void)right;

// 选择与开始的操作
- (void)select;
- (void)start;

// 按钮
- (void)commandA;
- (void)commandB;
- (void)commandC;
- (void)commandD;
@end

#import "ComponentGame.h"

@implementation ComponentGame
- (void)up {
    NSLog(@"up");
}

- (void)down {
    NSLog(@"down");
}

- (void)left {
    NSLog(@"left");
}

- (void)right {
    NSLog(@"right");
}
@end

• ComponentGame (Cheat)

#import "ComponentGame.h"

@interface ComponentGame (Cheat)

- (void)cheat;

@property (nonatomic, copy)NSString *coin;

@end

#import "ComponentGame+Cheat.h"
#import 

static const NSString *coinStr = @"coinStr";

@implementation ComponentGame (Cheat)

- (void)cheat {
    // 作弊操作
    [self up];
    [self up];
    
    [self down];
    [self down];
    
    [self commandA];
    [self commandA];
}


- (void)setCoin:(NSString *)coin
{
    objc_setAssociatedObject(self, (__bridge const void *)coinStr, coin, OBJC_ASSOCIATION_ASSIGN);
}

- (NSString *)coin
{
    NSString *coins = objc_getAssociatedObject(self, (__bridge const void *)coinStr);
    
    return coins;
}
@end

Demo